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commit f85086f95fa36194eb0db5cd5c12e56801b98523 upstream.
In register_mem_sect_under_node() the system_state's value is checked to
detect whether the call is made during boot time or during an hot-plug
operation. Unfortunately, that check against SYSTEM_BOOTING is wrong
because regular memory is registered at SYSTEM_SCHEDULING state. In
addition, memory hot-plug operation can be triggered at this system
state by the ACPI [1]. So checking against the system state is not
enough.
The consequence is that on system with interleaved node's ranges like this:
Early memory node ranges
node 1: [mem 0x0000000000000000-0x000000011fffffff]
node 2: [mem 0x0000000120000000-0x000000014fffffff]
node 1: [mem 0x0000000150000000-0x00000001ffffffff]
node 0: [mem 0x0000000200000000-0x000000048fffffff]
node 2: [mem 0x0000000490000000-0x00000007ffffffff]
This can be seen on PowerPC LPAR after multiple memory hot-plug and
hot-unplug operations are done. At the next reboot the node's memory
ranges can be interleaved and since the call to link_mem_sections() is
made in topology_init() while the system is in the SYSTEM_SCHEDULING
state, the node's id is not checked, and the sections registered to
multiple nodes:
$ ls -l /sys/devices/system/memory/memory21/node*
total 0
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node1 -> ../../node/node1
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node2 -> ../../node/node2
In that case, the system is able to boot but if later one of theses
memory blocks is hot-unplugged and then hot-plugged, the sysfs
inconsistency is detected and this is triggering a BUG_ON():
kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4
CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25
Call Trace:
add_memory_resource+0x23c/0x340 (unreliable)
__add_memory+0x5c/0xf0
dlpar_add_lmb+0x1b4/0x500
dlpar_memory+0x1f8/0xb80
handle_dlpar_errorlog+0xc0/0x190
dlpar_store+0x198/0x4a0
kobj_attr_store+0x30/0x50
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
vfs_write+0xe8/0x290
ksys_write+0xdc/0x130
system_call_exception+0x160/0x270
system_call_common+0xf0/0x27c
This patch addresses the root cause by not relying on the system_state
value to detect whether the call is due to a hot-plug operation. An
extra parameter is added to link_mem_sections() detailing whether the
operation is due to a hot-plug operation.
[1] According to Oscar Salvador, using this qemu command line, ACPI
memory hotplug operations are raised at SYSTEM_SCHEDULING state:
$QEMU -enable-kvm -machine pc -smp 4,sockets=4,cores=1,threads=1 -cpu host -monitor pty \
-m size=$MEM,slots=255,maxmem=4294967296k \
-numa node,nodeid=0,cpus=0-3,mem=512 -numa node,nodeid=1,mem=512 \
-object memory-backend-ram,id=memdimm0,size=134217728 -device pc-dimm,node=0,memdev=memdimm0,id=dimm0,slot=0 \
-object memory-backend-ram,id=memdimm1,size=134217728 -device pc-dimm,node=0,memdev=memdimm1,id=dimm1,slot=1 \
-object memory-backend-ram,id=memdimm2,size=134217728 -device pc-dimm,node=0,memdev=memdimm2,id=dimm2,slot=2 \
-object memory-backend-ram,id=memdimm3,size=134217728 -device pc-dimm,node=0,memdev=memdimm3,id=dimm3,slot=3 \
-object memory-backend-ram,id=memdimm4,size=134217728 -device pc-dimm,node=1,memdev=memdimm4,id=dimm4,slot=4 \
-object memory-backend-ram,id=memdimm5,size=134217728 -device pc-dimm,node=1,memdev=memdimm5,id=dimm5,slot=5 \
-object memory-backend-ram,id=memdimm6,size=134217728 -device pc-dimm,node=1,memdev=memdimm6,id=dimm6,slot=6 \
Fixes: 4fbce633910e ("mm/memory_hotplug.c: make register_mem_sect_under_node() a callback of walk_memory_range()")
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200915094143.79181-3-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c1d0da83358a2316d9be7f229f26126dbaa07468 upstream.
Patch series "mm: fix memory to node bad links in sysfs", v3.
Sometimes, firmware may expose interleaved memory layout like this:
Early memory node ranges
node 1: [mem 0x0000000000000000-0x000000011fffffff]
node 2: [mem 0x0000000120000000-0x000000014fffffff]
node 1: [mem 0x0000000150000000-0x00000001ffffffff]
node 0: [mem 0x0000000200000000-0x000000048fffffff]
node 2: [mem 0x0000000490000000-0x00000007ffffffff]
In that case, we can see memory blocks assigned to multiple nodes in
sysfs:
$ ls -l /sys/devices/system/memory/memory21
total 0
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node1 -> ../../node/node1
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node2 -> ../../node/node2
-rw-r--r-- 1 root root 65536 Aug 24 05:27 online
-r--r--r-- 1 root root 65536 Aug 24 05:27 phys_device
-r--r--r-- 1 root root 65536 Aug 24 05:27 phys_index
drwxr-xr-x 2 root root 0 Aug 24 05:27 power
-r--r--r-- 1 root root 65536 Aug 24 05:27 removable
-rw-r--r-- 1 root root 65536 Aug 24 05:27 state
lrwxrwxrwx 1 root root 0 Aug 24 05:25 subsystem -> ../../../../bus/memory
-rw-r--r-- 1 root root 65536 Aug 24 05:25 uevent
-r--r--r-- 1 root root 65536 Aug 24 05:27 valid_zones
The same applies in the node's directory with a memory21 link in both
the node1 and node2's directory.
This is wrong but doesn't prevent the system to run. However when
later, one of these memory blocks is hot-unplugged and then hot-plugged,
the system is detecting an inconsistency in the sysfs layout and a
BUG_ON() is raised:
kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084!
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4
CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25
Call Trace:
add_memory_resource+0x23c/0x340 (unreliable)
__add_memory+0x5c/0xf0
dlpar_add_lmb+0x1b4/0x500
dlpar_memory+0x1f8/0xb80
handle_dlpar_errorlog+0xc0/0x190
dlpar_store+0x198/0x4a0
kobj_attr_store+0x30/0x50
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
vfs_write+0xe8/0x290
ksys_write+0xdc/0x130
system_call_exception+0x160/0x270
system_call_common+0xf0/0x27c
This has been seen on PowerPC LPAR.
The root cause of this issue is that when node's memory is registered,
the range used can overlap another node's range, thus the memory block
is registered to multiple nodes in sysfs.
There are two issues here:
(a) The sysfs memory and node's layouts are broken due to these
multiple links
(b) The link errors in link_mem_sections() should not lead to a system
panic.
To address (a) register_mem_sect_under_node should not rely on the
system state to detect whether the link operation is triggered by a hot
plug operation or not. This is addressed by the patches 1 and 2 of this
series.
Issue (b) will be addressed separately.
This patch (of 2):
The memmap_context enum is used to detect whether a memory operation is
due to a hot-add operation or happening at boot time.
Make it general to the hotplug operation and rename it as
meminit_context.
There is no functional change introduced by this patch
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200915094143.79181-1-ldufour@linux.ibm.com
Link: https://lkml.kernel.org/r/20200915132624.9723-1-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d3f7b1bb204099f2f7306318896223e8599bb6a2 upstream.
Currently to make sure that every page table entry is read just once
gup_fast walks perform READ_ONCE and pass pXd value down to the next
gup_pXd_range function by value e.g.:
static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
...
pudp = pud_offset(&p4d, addr);
This function passes a reference on that local value copy to pXd_offset,
and might get the very same pointer in return. This happens when the
level is folded (on most arches), and that pointer should not be
iterated.
On s390 due to the fact that each task might have different 5,4 or
3-level address translation and hence different levels folded the logic
is more complex and non-iteratable pointer to a local copy leads to
severe problems.
Here is an example of what happens with gup_fast on s390, for a task
with 3-level paging, crossing a 2 GB pud boundary:
// addr = 0x1007ffff000, end = 0x10080001000
static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
{
unsigned long next;
pud_t *pudp;
// pud_offset returns &p4d itself (a pointer to a value on stack)
pudp = pud_offset(&p4d, addr);
do {
// on second iteratation reading "random" stack value
pud_t pud = READ_ONCE(*pudp);
// next = 0x10080000000, due to PUD_SIZE/MASK != PGDIR_SIZE/MASK on s390
next = pud_addr_end(addr, end);
...
} while (pudp++, addr = next, addr != end); // pudp++ iterating over stack
return 1;
}
This happens since s390 moved to common gup code with commit
d1874a0c2805 ("s390/mm: make the pxd_offset functions more robust") and
commit 1a42010cdc26 ("s390/mm: convert to the generic
get_user_pages_fast code").
s390 tried to mimic static level folding by changing pXd_offset
primitives to always calculate top level page table offset in pgd_offset
and just return the value passed when pXd_offset has to act as folded.
What is crucial for gup_fast and what has been overlooked is that
PxD_SIZE/MASK and thus pXd_addr_end should also change correspondingly.
And the latter is not possible with dynamic folding.
To fix the issue in addition to pXd values pass original pXdp pointers
down to gup_pXd_range functions. And introduce pXd_offset_lockless
helpers, which take an additional pXd entry value parameter. This has
already been discussed in
https://lkml.kernel.org/r/20190418100218.0a4afd51@mschwideX1
Fixes: 1a42010cdc26 ("s390/mm: convert to the generic get_user_pages_fast code")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: <stable@vger.kernel.org> [5.2+]
Link: https://lkml.kernel.org/r/patch.git-943f1e5dcff2.your-ad-here.call-01599856292-ext-8676@work.hours
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 41663430588c737dd735bad5a0d1ba325dcabd59 upstream.
SWP_FS is used to make swap_{read,write}page() go through the
filesystem, and it's only used for swap files over NFS. So, !SWP_FS
means non NFS for now, it could be either file backed or device backed.
Something similar goes with legacy SWP_FILE.
So in order to achieve the goal of the original patch, SWP_BLKDEV should
be used instead.
FS corruption can be observed with SSD device + XFS + fragmented
swapfile due to CONFIG_THP_SWAP=y.
I reproduced the issue with the following details:
Environment:
QEMU + upstream kernel + buildroot + NVMe (2 GB)
Kernel config:
CONFIG_BLK_DEV_NVME=y
CONFIG_THP_SWAP=y
Some reproducible steps:
mkfs.xfs -f /dev/nvme0n1
mkdir /tmp/mnt
mount /dev/nvme0n1 /tmp/mnt
bs="32k"
sz="1024m" # doesn't matter too much, I also tried 16m
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -F -S 0 -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fsync" /tmp/mnt/sw
mkswap /tmp/mnt/sw
swapon /tmp/mnt/sw
stress --vm 2 --vm-bytes 600M # doesn't matter too much as well
Symptoms:
- FS corruption (e.g. checksum failure)
- memory corruption at: 0xd2808010
- segfault
Fixes: f0eea189e8e9 ("mm, THP, swap: Don't allocate huge cluster for file backed swap device")
Fixes: 38d8b4e6bdc8 ("mm, THP, swap: delay splitting THP during swap out")
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Eric Sandeen <esandeen@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200820045323.7809-1-hsiangkao@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit ce2684254bd4818ca3995c0d021fb62c4cf10a19 ]
syzbot reported the following KASAN splat:
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 1 PID: 6826 Comm: syz-executor142 Not tainted 5.9.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__lock_acquire+0x84/0x2ae0 kernel/locking/lockdep.c:4296
Code: ff df 8a 04 30 84 c0 0f 85 e3 16 00 00 83 3d 56 58 35 08 00 0f 84 0e 17 00 00 83 3d 25 c7 f5 07 00 74 2c 4c 89 e8 48 c1 e8 03 <80> 3c 30 00 74 12 4c 89 ef e8 3e d1 5a 00 48 be 00 00 00 00 00 fc
RSP: 0018:ffffc90004b9f850 EFLAGS: 00010006
Call Trace:
lock_acquire+0x140/0x6f0 kernel/locking/lockdep.c:5006
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
madvise_cold_or_pageout_pte_range+0x52f/0x25c0 mm/madvise.c:389
walk_pmd_range mm/pagewalk.c:89 [inline]
walk_pud_range mm/pagewalk.c:160 [inline]
walk_p4d_range mm/pagewalk.c:193 [inline]
walk_pgd_range mm/pagewalk.c:229 [inline]
__walk_page_range+0xe7b/0x1da0 mm/pagewalk.c:331
walk_page_range+0x2c3/0x5c0 mm/pagewalk.c:427
madvise_pageout_page_range mm/madvise.c:521 [inline]
madvise_pageout mm/madvise.c:557 [inline]
madvise_vma mm/madvise.c:946 [inline]
do_madvise+0x12d0/0x2090 mm/madvise.c:1145
__do_sys_madvise mm/madvise.c:1171 [inline]
__se_sys_madvise mm/madvise.c:1169 [inline]
__x64_sys_madvise+0x76/0x80 mm/madvise.c:1169
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The backing vma was shmem.
In case of split page of file-backed THP, madvise zaps the pmd instead
of remapping of sub-pages. So we need to check pmd validity after
split.
Reported-by: syzbot+ecf80462cb7d5d552bc7@syzkaller.appspotmail.com
Fixes: 1a4e58cce84e ("mm: introduce MADV_PAGEOUT")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit e3336cab2579012b1e72b5265adf98e2d6e244ad upstream.
We've met softlockup with "CONFIG_PREEMPT_NONE=y", when the target memcg
doesn't have any reclaimable memory.
It can be easily reproduced as below:
watchdog: BUG: soft lockup - CPU#0 stuck for 111s![memcg_test:2204]
CPU: 0 PID: 2204 Comm: memcg_test Not tainted 5.9.0-rc2+ #12
Call Trace:
shrink_lruvec+0x49f/0x640
shrink_node+0x2a6/0x6f0
do_try_to_free_pages+0xe9/0x3e0
try_to_free_mem_cgroup_pages+0xef/0x1f0
try_charge+0x2c1/0x750
mem_cgroup_charge+0xd7/0x240
__add_to_page_cache_locked+0x2fd/0x370
add_to_page_cache_lru+0x4a/0xc0
pagecache_get_page+0x10b/0x2f0
filemap_fault+0x661/0xad0
ext4_filemap_fault+0x2c/0x40
__do_fault+0x4d/0xf9
handle_mm_fault+0x1080/0x1790
It only happens on our 1-vcpu instances, because there's no chance for
oom reaper to run to reclaim the to-be-killed process.
Add a cond_resched() at the upper shrink_node_memcgs() to solve this
issue, this will mean that we will get a scheduling point for each memcg
in the reclaimed hierarchy without any dependency on the reclaimable
memory in that memcg thus making it more predictable.
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/1598495549-67324-1-git-send-email-xlpang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: b0dedc49a2da ("mm/vmscan.c: iterate only over charged shrinkers during memcg shrink_slab()")
Cc: stable@vger.kernel.org
Signed-off-by: Julius Hemanth Pitti <jpitti@cisco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9683182612214aa5f5e709fad49444b847cd866a upstream.
There is a race during page offline that can lead to infinite loop:
a page never ends up on a buddy list and __offline_pages() keeps
retrying infinitely or until a termination signal is received.
Thread#1 - a new process:
load_elf_binary
begin_new_exec
exec_mmap
mmput
exit_mmap
tlb_finish_mmu
tlb_flush_mmu
release_pages
free_unref_page_list
free_unref_page_prepare
set_pcppage_migratetype(page, migratetype);
// Set page->index migration type below MIGRATE_PCPTYPES
Thread#2 - hot-removes memory
__offline_pages
start_isolate_page_range
set_migratetype_isolate
set_pageblock_migratetype(page, MIGRATE_ISOLATE);
Set migration type to MIGRATE_ISOLATE-> set
drain_all_pages(zone);
// drain per-cpu page lists to buddy allocator.
Thread#1 - continue
free_unref_page_commit
migratetype = get_pcppage_migratetype(page);
// get old migration type
list_add(&page->lru, &pcp->lists[migratetype]);
// add new page to already drained pcp list
Thread#2
Never drains pcp again, and therefore gets stuck in the loop.
The fix is to try to drain per-cpu lists again after
check_pages_isolated_cb() fails.
Fixes: c52e75935f8d ("mm: remove extra drain pages on pcp list")
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200903140032.380431-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20200904151448.100489-2-pasha.tatashin@soleen.com
Link: http://lkml.kernel.org/r/20200904070235.GA15277@dhcp22.suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ec0abae6dcdf7ef88607c869bf35a4b63ce1b370 upstream.
A migrating transparent huge page has to already be unmapped. Otherwise,
the page could be modified while it is being copied to a new page and data
could be lost. The function __split_huge_pmd() checks for a PMD migration
entry before calling __split_huge_pmd_locked() leading one to think that
__split_huge_pmd_locked() can handle splitting a migrating PMD.
However, the code always increments the page->_mapcount and adjusts the
memory control group accounting assuming the page is mapped.
Also, if the PMD entry is a migration PMD entry, the call to
is_huge_zero_pmd(*pmd) is incorrect because it calls pmd_pfn(pmd) instead
of migration_entry_to_pfn(pmd_to_swp_entry(pmd)). Fix these problems by
checking for a PMD migration entry.
Fixes: 84c3fc4e9c56 ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org> [4.14+]
Link: https://lkml.kernel.org/r/20200903183140.19055-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 62fdb1632bcbed30c40f6bd2b58297617e442658 upstream.
Patch series "mm: fixes to past from future testing".
Here's a set of independent fixes against 5.9-rc2: prompted by
testing Alex Shi's "warning on !memcg" and lru_lock series, but
I think fit for 5.9 - though maybe only the first for stable.
This patch (of 5):
In 5.8 some instances of memcg charging in do_swap_page() and unuse_pte()
were removed, on the understanding that swap cache is now already charged
at those points; but a case was missed, when ksm_might_need_to_copy() has
decided it must allocate a substitute page: such pages were never charged.
Fix it inside ksm_might_need_to_copy().
This was discovered by Alex Shi's prospective commit "mm/memcg: warning on
!memcg after readahead page charged".
But there is a another surprise: this also fixes some rarer uncharged
PageAnon cases, when KSM is configured in, but has never been activated.
ksm_might_need_to_copy()'s anon_vma->root and linear_page_index() check
sometimes catches a case which would need to have been copied if KSM were
turned on. Or that's my optimistic interpretation (of my own old code),
but it leaves some doubt as to whether everything is working as intended
there - might it hint at rare anon ptes which rmap cannot find? A
question not easily answered: put in the fix for missed memcg charges.
Cc; Matthew Wilcox <willy@infradead.org>
Fixes: 4c6355b25e8b ("mm: memcontrol: charge swapin pages on instantiation")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org> [5.8]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301343270.5954@eggly.anvils
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301358020.5954@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b3b33d3c43bbe0177d70653f4e889c78cc37f097 upstream.
Variable populated, which is a member of struct pcpu_chunk, is used as a
unit of size of unsigned long.
However, size of populated is miscounted. So, I fix this minor part.
Fixes: 8ab16c43ea79 ("percpu: change the number of pages marked in the first_chunk pop bitmap")
Cc: <stable@vger.kernel.org> # 4.14+
Signed-off-by: Sunghyun Jin <mcsmonk@gmail.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e5a59d308f52bb0052af5790c22173651b187465 upstream.
collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to
be read to page_cache_sync_readahead(). The intent was probably to read
a single page. Fix it to use the number of pages to the end of the
window instead.
Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 17743798d81238ab13050e8e2833699b54e15467 upstream.
There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.
CPU0: CPU1:
proc_sys_write
hugetlb_sysctl_handler proc_sys_call_handler
hugetlb_sysctl_handler_common hugetlb_sysctl_handler
table->data = &tmp; hugetlb_sysctl_handler_common
table->data = &tmp;
proc_doulongvec_minmax
do_proc_doulongvec_minmax sysctl_head_finish
__do_proc_doulongvec_minmax unuse_table
i = table->data;
*i = val; // corrupt CPU1's stack
Fix this by duplicating the `table`, and only update the duplicate of
it. And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.
The following oops was seen:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
Code: Bad RIP value.
...
Call Trace:
? set_max_huge_pages+0x3da/0x4f0
? alloc_pool_huge_page+0x150/0x150
? proc_doulongvec_minmax+0x46/0x60
? hugetlb_sysctl_handler_common+0x1c7/0x200
? nr_hugepages_store+0x20/0x20
? copy_fd_bitmaps+0x170/0x170
? hugetlb_sysctl_handler+0x1e/0x20
? proc_sys_call_handler+0x2f1/0x300
? unregister_sysctl_table+0xb0/0xb0
? __fd_install+0x78/0x100
? proc_sys_write+0x14/0x20
? __vfs_write+0x4d/0x90
? vfs_write+0xef/0x240
? ksys_write+0xc0/0x160
? __ia32_sys_read+0x50/0x50
? __close_fd+0x129/0x150
? __x64_sys_write+0x43/0x50
? do_syscall_64+0x6c/0x200
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: e5ff215941d5 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 953f064aa6b29debcc211869b60bd59f26d19c34 upstream.
Since commit cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic
hugepages using cma"), the gigantic page would be allocated from node
which is not the preferred node, although there are pages available from
that node. The reason is that the nid parameter has been ignored in
alloc_gigantic_page().
Besides, the __GFP_THISNODE also need be checked if user required to
alloc only from the preferred node.
After this patch, the preferred node is tried first before other allowed
nodes, and don't try to allocate from other nodes if __GFP_THISNODE is
specified. If user don't specify the preferred node, the current node
will be used as preferred node, which makes sure consistent behavior of
allocating gigantic and non-gigantic hugetlb page.
Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: https://lkml.kernel.org/r/20200902025016.697260-1-lixinhai.lxh@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ebdf8321eeeb623aed60f7ed16f7445363230118 upstream.
Commit f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration")
introduced support for tracking the uffd wp bit during page migration.
However the non-swap PTE variant was used to set the flag for zone device
private pages which are a type of swap page.
This leads to corruption of the swap offset if the original PTE has the
uffd_wp flag set.
Fixes: f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ad7df764b7e1c7dc64e016da7ada2e3e1bb90700 upstream.
During memory migration a pte is temporarily replaced with a migration
swap pte. Some pte bits from the existing mapping such as the soft-dirty
and uffd write-protect bits are preserved by copying these to the
temporary migration swap pte.
However these bits are not stored at the same location for swap and
non-swap ptes. Therefore testing these bits requires using the
appropriate helper function for the given pte type.
Unfortunately several code locations were found where the wrong helper
function is being used to test soft_dirty and uffd_wp bits which leads to
them getting incorrectly set or cleared during page-migration.
Fix these by using the correct tests based on pte type.
Fixes: a5430dda8a3a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Fixes: 8c3328f1f36a ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7867fd7cc44e63c6673cd0f8fea155456d34d0de upstream.
The syzbot reported the below use-after-free:
BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline]
BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline]
BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145
Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996
CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
madvise_willneed mm/madvise.c:293 [inline]
madvise_vma mm/madvise.c:942 [inline]
do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145
do_madvise mm/madvise.c:1169 [inline]
__do_sys_madvise mm/madvise.c:1171 [inline]
__se_sys_madvise mm/madvise.c:1169 [inline]
__x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Allocated by task 9992:
kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482
vm_area_alloc+0x1c/0x110 kernel/fork.c:347
mmap_region+0x8e5/0x1780 mm/mmap.c:1743
do_mmap+0xcf9/0x11d0 mm/mmap.c:1545
vm_mmap_pgoff+0x195/0x200 mm/util.c:506
ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 9992:
kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693
remove_vma+0x132/0x170 mm/mmap.c:184
remove_vma_list mm/mmap.c:2613 [inline]
__do_munmap+0x743/0x1170 mm/mmap.c:2869
do_munmap mm/mmap.c:2877 [inline]
mmap_region+0x257/0x1780 mm/mmap.c:1716
do_mmap+0xcf9/0x11d0 mm/mmap.c:1545
vm_mmap_pgoff+0x195/0x200 mm/util.c:506
ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
It is because vma is accessed after releasing mmap_lock, but someone
else acquired the mmap_lock and the vma is gone.
Releasing mmap_lock after accessing vma should fix the problem.
Fixes: 692fe62433d4c ("mm: Handle MADV_WILLNEED through vfs_fadvise()")
Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org> [5.4+]
Link: https://lkml.kernel.org/r/20200816141204.162624-1-shy828301@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e80d3909be42f7e38cc350c1ba109cf0aa51956a upstream.
__apply_to_page_range() is also used to change and/or allocate
page-table pages in the vmalloc area of the address space. Make sure
these changes get synchronized to other page-tables in the system by
calling arch_sync_kernel_mappings() when necessary.
The impact appears limited to x86-32, where apply_to_page_range may miss
updating the PMD. That leads to explosions in drivers like
BUG: unable to handle page fault for address: fe036000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
*pde = 00000000
Oops: 0002 [#1] SMP
CPU: 3 PID: 1300 Comm: gem_concurrent_ Not tainted 5.9.0-rc1+ #16
Hardware name: /NUC6i3SYB, BIOS SYSKLi35.86A.0024.2015.1027.2142 10/27/2015
EIP: __execlists_context_alloc+0x132/0x2d0 [i915]
Code: 31 d2 89 f0 e8 2f 55 02 00 89 45 e8 3d 00 f0 ff ff 0f 87 11 01 00 00 8b 4d e8 03 4b 30 b8 5a 5a 5a 5a ba 01 00 00 00 8d 79 04 <c7> 01 5a 5a 5a 5a c7 81 fc 0f 00 00 5a 5a 5a 5a 83 e7 fc 29 f9 81
EAX: 5a5a5a5a EBX: f60ca000 ECX: fe036000 EDX: 00000001
ESI: f43b7340 EDI: fe036004 EBP: f6389cb8 ESP: f6389c9c
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010286
CR0: 80050033 CR2: fe036000 CR3: 2d361000 CR4: 001506d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: fffe0ff0 DR7: 00000400
Call Trace:
execlists_context_alloc+0x10/0x20 [i915]
intel_context_alloc_state+0x3f/0x70 [i915]
__intel_context_do_pin+0x117/0x170 [i915]
i915_gem_do_execbuffer+0xcc7/0x2500 [i915]
i915_gem_execbuffer2_ioctl+0xcd/0x1f0 [i915]
drm_ioctl_kernel+0x8f/0xd0
drm_ioctl+0x223/0x3d0
__ia32_sys_ioctl+0x1ab/0x760
__do_fast_syscall_32+0x3f/0x70
do_fast_syscall_32+0x29/0x60
do_SYSENTER_32+0x15/0x20
entry_SYSENTER_32+0x9f/0xf2
EIP: 0xb7f28559
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90 8d 76
EAX: ffffffda EBX: 00000005 ECX: c0406469 EDX: bf95556c
ESI: b7e68000 EDI: c0406469 EBP: 00000005 ESP: bf9554d8
DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000296
Modules linked in: i915 x86_pkg_temp_thermal intel_powerclamp crc32_pclmul crc32c_intel intel_cstate intel_uncore intel_gtt drm_kms_helper intel_pch_thermal video button autofs4 i2c_i801 i2c_smbus fan
CR2: 00000000fe036000
It looks like kasan, xen and i915 are vulnerable.
Actual impact is "on thinkpad X60 in 5.9-rc1, screen starts blinking
after 30-or-so minutes, and machine is unusable"
[sfr@canb.auug.org.au: ARCH_PAGE_TABLE_SYNC_MASK needs vmalloc.h]
Link: https://lkml.kernel.org/r/20200825172508.16800a4f@canb.auug.org.au
[chris@chris-wilson.co.uk: changelog addition]
[pavel@ucw.cz: changelog addition]
Fixes: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified")
Fixes: 86cf69f1d893 ("x86/mm/32: implement arch_sync_kernel_mappings()")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk> [x86-32]
Tested-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org> [5.8+]
Link: https://lkml.kernel.org/r/20200821123746.16904-1-joro@8bytes.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit dc07a728d49cf025f5da2c31add438d839d076c0 upstream.
Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in
deactivate_slab()") suffered an update when picked up from LKML [1].
Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()'
created a no-op statement. Fix it by sticking to the behavior intended
in the original patch [1]. In addition, make freelist_corrupted()
immune to passing NULL instead of &freelist.
The issue has been spotted via static analysis and code review.
[1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/
Fixes: 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200824130643.10291-1-erosca@de.adit-jv.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9fa2dd946743ae6f30dc4830da19147bf100a7f2 upstream.
Gate pages were missed when converting from get to pin_user_pages().
This can lead to refcount imbalances. This is reliably and quickly
reproducible running the x86 selftests when vsyscall=emulate is enabled
(the default). Fix by using try_grab_page() with appropriate flags
passed.
The long story:
Today, pin_user_pages() and get_user_pages() are similar interfaces for
manipulating page reference counts. However, "pins" use a "bias" value
and manipulate the actual reference count by 1024 instead of 1 used by
plain "gets".
That means that pin_user_pages() must be matched with unpin_user_pages()
and can't be mixed with a plain put_user_pages() or put_page().
Enter gate pages, like the vsyscall page. They are pages usually in the
kernel image, but which are mapped to userspace. Userspace is allowed
access to them, including interfaces using get/pin_user_pages(). The
refcount of these kernel pages is manipulated just like a normal user
page on the get/pin side so that the put/unpin side can work the same
for normal user pages or gate pages.
get_gate_page() uses try_get_page() which only bumps the refcount by
1, not 1024, even if called in the pin_user_pages() path. If someone
pins a gate page, this happens:
pin_user_pages()
get_gate_page()
try_get_page() // bump refcount +1
... some time later
unpin_user_pages()
page_ref_sub_and_test(page, 1024))
... and boom, we get a refcount off by 1023. This is reliably and
quickly reproducible running the x86 selftests when booted with
vsyscall=emulate (the default). The selftests use ptrace(), but I
suspect anything using pin_user_pages() on gate pages could hit this.
To fix it, simply use try_grab_page() instead of try_get_page(), and
pass 'gup_flags' in so that FOLL_PIN can be respected.
This bug traces back to the very beginning of the FOLL_PIN support in
commit 3faa52c03f44 ("mm/gup: track FOLL_PIN pages"), which showed up in
the 5.7 release.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Fixes: 3faa52c03f44 ("mm/gup: track FOLL_PIN pages")
Reported-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 6e4bd50f3888fa8fea8bc66a0ad4ad5f1c862961 upstream.
Commit 3e32cb2e0a12 ("mm: memcontrol: lockless page counters") could had
memcg->memsw->watermark and memcg->memsw->failcnt been accessed
concurrently as reported by KCSAN,
BUG: KCSAN: data-race in page_counter_try_charge / page_counter_try_charge
read to 0xffff8fb18c4cd190 of 8 bytes by task 1081 on cpu 59:
page_counter_try_charge+0x4d/0x150 mm/page_counter.c:138
try_charge+0x131/0xd50 mm/memcontrol.c:2405
__memcg_kmem_charge_memcg+0x58/0x140
__memcg_kmem_charge+0xcc/0x280
__alloc_pages_nodemask+0x1e1/0x450
alloc_pages_current+0xa6/0x120
pte_alloc_one+0x17/0xd0
__pte_alloc+0x3a/0x1f0
copy_p4d_range+0xc36/0x1990
copy_page_range+0x21d/0x360
dup_mmap+0x5f5/0x7a0
dup_mm+0xa2/0x240
copy_process+0x1b3f/0x3460
_do_fork+0xaa/0xa20
__x64_sys_clone+0x13b/0x170
do_syscall_64+0x91/0xb47
entry_SYSCALL_64_after_hwframe+0x49/0xbe
write to 0xffff8fb18c4cd190 of 8 bytes by task 1153 on cpu 120:
page_counter_try_charge+0x5b/0x150 mm/page_counter.c:139
try_charge+0x131/0xd50 mm/memcontrol.c:2405
mem_cgroup_try_charge+0x159/0x460
mem_cgroup_try_charge_delay+0x3d/0xa0
wp_page_copy+0x14d/0x930
do_wp_page+0x107/0x7b0
__handle_mm_fault+0xce6/0xd40
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
BUG: KCSAN: data-race in page_counter_try_charge / page_counter_try_charge
write to 0xffff88809bbf2158 of 8 bytes by task 11782 on cpu 0:
page_counter_try_charge+0x100/0x170 mm/page_counter.c:129
try_charge+0x185/0xbf0 mm/memcontrol.c:2405
__memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837
__memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877
__alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780
read to 0xffff88809bbf2158 of 8 bytes by task 11814 on cpu 1:
page_counter_try_charge+0xef/0x170 mm/page_counter.c:129
try_charge+0x185/0xbf0 mm/memcontrol.c:2405
__memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837
__memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877
__alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780
Since watermark could be compared or set to garbage due to a data race
which would change the code logic, fix it by adding a pair of READ_ONCE()
and WRITE_ONCE() in those places.
The "failcnt" counter is tolerant of some degree of inaccuracy and is only
used to report stats, a data race will not be harmful, thus mark it as an
intentional data race using the data_race() macro.
Fixes: 3e32cb2e0a12 ("mm: memcontrol: lockless page counters")
Reported-by: syzbot+f36cfe60b1006a94f9dc@syzkaller.appspotmail.com
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/1581519682-23594-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit bbe98f9cadff58cdd6a4acaeba0efa8565dabe65 ]
Move collapse_huge_page()'s mmget_still_valid() check into
khugepaged_test_exit() itself. collapse_huge_page() is used for anon THP
only, and earned its mmget_still_valid() check because it inserts a huge
pmd entry in place of the page table's pmd entry; whereas
collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp()
merely clears the page table's pmd entry. But core dumping without mmap
lock must have been as open to mistaking a racily cleared pmd entry for a
page table at physical page 0, as exit_mmap() was. And we certainly have
no interest in mapping as a THP once dumping core.
Fixes: 59ea6d06cfa9 ("coredump: fix race condition between collapse_huge_page() and core dumping")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021217020.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
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commit b7333b58f358f38d90d78e00c1ee5dec82df10ad upstream.
Recently we found regression when running will_it_scale/page_fault3 test
on ARM64. Over 70% down for the multi processes cases and over 20% down
for the multi threads cases. It turns out the regression is caused by
commit 89b15332af7c ("mm: drop mmap_sem before calling
balance_dirty_pages() in write fault").
The test mmaps a memory size file then write to the mapping, this would
make all memory dirty and trigger dirty pages throttle, that upstream
commit would release mmap_sem then retry the page fault. The retried
page fault would see correct PTEs installed then just fall through to
spurious TLB flush. The regression is caused by the excessive spurious
TLB flush. It is fine on x86 since x86's spurious TLB flush is no-op.
We could just skip the spurious TLB flush to mitigate the regression.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Xu Yu <xuyu@linux.alibaba.com>
Debugged-by: Xu Yu <xuyu@linux.alibaba.com>
Tested-by: Xu Yu <xuyu@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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commit 88e8ac11d2ea3acc003cf01bb5a38c8aa76c3cfd upstream.
The following race is observed with the repeated online, offline and a
delay between two successive online of memory blocks of movable zone.
P1 P2
Online the first memory block in
the movable zone. The pcp struct
values are initialized to default
values,i.e., pcp->high = 0 &
pcp->batch = 1.
Allocate the pages from the
movable zone.
Try to Online the second memory
block in the movable zone thus it
entered the online_pages() but yet
to call zone_pcp_update().
This process is entered into
the exit path thus it tries
to release the order-0 pages
to pcp lists through
free_unref_page_commit().
As pcp->high = 0, pcp->count = 1
proceed to call the function
free_pcppages_bulk().
Update the pcp values thus the
new pcp values are like, say,
pcp->high = 378, pcp->batch = 63.
Read the pcp's batch value using
READ_ONCE() and pass the same to
free_pcppages_bulk(), pcp values
passed here are, batch = 63,
count = 1.
Since num of pages in the pcp
lists are less than ->batch,
then it will stuck in
while(list_empty(list)) loop
with interrupts disabled thus
a core hung.
Avoid this by ensuring free_pcppages_bulk() is called with proper count of
pcp list pages.
The mentioned race is some what easily reproducible without [1] because
pcp's are not updated for the first memory block online and thus there is
a enough race window for P2 between alloc+free and pcp struct values
update through onlining of second memory block.
With [1], the race still exists but it is very narrow as we update the pcp
struct values for the first memory block online itself.
This is not limited to the movable zone, it could also happen in cases
with the normal zone (e.g., hotplug to a node that only has DMA memory, or
no other memory yet).
[1]: https://patchwork.kernel.org/patch/11696389/
Fixes: 5f8dcc21211a ("page-allocator: split per-cpu list into one-list-per-migrate-type")
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: <stable@vger.kernel.org> [2.6+]
Link: http://lkml.kernel.org/r/1597150703-19003-1-git-send-email-charante@codeaurora.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e08d3fdfe2dafa0331843f70ce1ff6c1c4900bf4 upstream.
The lowmem_reserve arrays provide a means of applying pressure against
allocations from lower zones that were targeted at higher zones. Its
values are a function of the number of pages managed by higher zones and
are assigned by a call to the setup_per_zone_lowmem_reserve() function.
The function is initially called at boot time by the function
init_per_zone_wmark_min() and may be called later by accesses of the
/proc/sys/vm/lowmem_reserve_ratio sysctl file.
The function init_per_zone_wmark_min() was moved up from a module_init to
a core_initcall to resolve a sequencing issue with khugepaged.
Unfortunately this created a sequencing issue with CMA page accounting.
The CMA pages are added to the managed page count of a zone when
cma_init_reserved_areas() is called at boot also as a core_initcall. This
makes it uncertain whether the CMA pages will be added to the managed page
counts of their zones before or after the call to
init_per_zone_wmark_min() as it becomes dependent on link order. With the
current link order the pages are added to the managed count after the
lowmem_reserve arrays are initialized at boot.
This means the lowmem_reserve values at boot may be lower than the values
used later if /proc/sys/vm/lowmem_reserve_ratio is accessed even if the
ratio values are unchanged.
In many cases the difference is not significant, but for example
an ARM platform with 1GB of memory and the following memory layout
cma: Reserved 256 MiB at 0x0000000030000000
Zone ranges:
DMA [mem 0x0000000000000000-0x000000002fffffff]
Normal empty
HighMem [mem 0x0000000030000000-0x000000003fffffff]
would result in 0 lowmem_reserve for the DMA zone. This would allow
userspace to deplete the DMA zone easily.
Funnily enough
$ cat /proc/sys/vm/lowmem_reserve_ratio
would fix up the situation because as a side effect it forces
setup_per_zone_lowmem_reserve.
This commit breaks the link order dependency by invoking
init_per_zone_wmark_min() as a postcore_initcall so that the CMA pages
have the chance to be properly accounted in their zone(s) and allowing
the lowmem_reserve arrays to receive consistent values.
Fixes: bc22af74f271 ("mm: update min_free_kbytes from khugepaged after core initialization")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1597423766-27849-1-git-send-email-opendmb@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e47110e90584a22e9980510b00d0dfad3a83354e upstream.
Like zap_pte_range add cond_resched so that we can avoid softlockups as
reported below. On non-preemptible kernel with large I/O map region (like
the one we get when using persistent memory with sector mode), an unmap of
the namespace can report below softlockups.
22724.027334] watchdog: BUG: soft lockup - CPU#49 stuck for 23s! [ndctl:50777]
NIP [c0000000000dc224] plpar_hcall+0x38/0x58
LR [c0000000000d8898] pSeries_lpar_hpte_invalidate+0x68/0xb0
Call Trace:
flush_hash_page+0x114/0x200
hpte_need_flush+0x2dc/0x540
vunmap_page_range+0x538/0x6f0
free_unmap_vmap_area+0x30/0x70
remove_vm_area+0xfc/0x140
__vunmap+0x68/0x270
__iounmap.part.0+0x34/0x60
memunmap+0x54/0x70
release_nodes+0x28c/0x300
device_release_driver_internal+0x16c/0x280
unbind_store+0x124/0x170
drv_attr_store+0x44/0x60
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
__vfs_write+0x3c/0x70
vfs_write+0xd8/0x260
ksys_write+0xdc/0x130
system_call+0x5c/0x70
Reported-by: Harish Sriram <harish@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200807075933.310240-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
[ Upstream commit f3f99d63a8156c7a4a6b20aac22b53c5579c7dc1 ]
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in
__khugepaged_enter(): yes, when one thread is about to dump core, has set
core_state, and is waiting for others, another might do something calling
__khugepaged_enter(), which now crashes because I lumped the core_state
test (known as "mmget_still_valid") into khugepaged_test_exit(). I still
think it's best to lump them together, so just in this exceptional case,
check mm->mm_users directly instead of khugepaged_test_exit().
Fixes: bbe98f9cadff ("khugepaged: khugepaged_test_exit() check mmget_still_valid()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit b4223a510e2ab1bf0f971d50af7c1431014b25ad upstream.
When check_memblock_offlined_cb() returns failed rc(e.g. the memblock is
online at that time), mem_hotplug_begin/done is unpaired in such case.
Therefore a warning:
Call Trace:
percpu_up_write+0x33/0x40
try_remove_memory+0x66/0x120
? _cond_resched+0x19/0x30
remove_memory+0x2b/0x40
dev_dax_kmem_remove+0x36/0x72 [kmem]
device_release_driver_internal+0xf0/0x1c0
device_release_driver+0x12/0x20
bus_remove_device+0xe1/0x150
device_del+0x17b/0x3e0
unregister_dev_dax+0x29/0x60
devm_action_release+0x15/0x20
release_nodes+0x19a/0x1e0
devres_release_all+0x3f/0x50
device_release_driver_internal+0x100/0x1c0
driver_detach+0x4c/0x8f
bus_remove_driver+0x5c/0xd0
driver_unregister+0x31/0x50
dax_pmem_exit+0x10/0xfe0 [dax_pmem]
Fixes: f1037ec0cc8a ("mm/memory_hotplug: fix remove_memory() lockdep splat")
Signed-off-by: Jia He <justin.he@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org> [5.6+]
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chuhong Yuan <hslester96@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Cc: Kaly Xin <Kaly.Xin@arm.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200710031619.18762-3-justin.he@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 3a5139f1c5bb76d69756fb8f13fffa173e261153 upstream.
The routine cma_init_reserved_areas is designed to activate all
reserved cma areas. It quits when it first encounters an error.
This can leave some areas in a state where they are reserved but
not activated. There is no feedback to code which performed the
reservation. Attempting to allocate memory from areas in such a
state will result in a BUG.
Modify cma_init_reserved_areas to always attempt to activate all
areas. The called routine, cma_activate_area is responsible for
leaving the area in a valid state. No one is making active use
of returned error codes, so change the routine to void.
How to reproduce: This example uses kernelcore, hugetlb and cma
as an easy way to reproduce. However, this is a more general cma
issue.
Two node x86 VM 16GB total, 8GB per node
Kernel command line parameters, kernelcore=4G hugetlb_cma=8G
Related boot time messages,
hugetlb_cma: reserve 8192 MiB, up to 4096 MiB per node
cma: Reserved 4096 MiB at 0x0000000100000000
hugetlb_cma: reserved 4096 MiB on node 0
cma: Reserved 4096 MiB at 0x0000000300000000
hugetlb_cma: reserved 4096 MiB on node 1
cma: CMA area hugetlb could not be activated
# echo 8 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
...
Call Trace:
bitmap_find_next_zero_area_off+0x51/0x90
cma_alloc+0x1a5/0x310
alloc_fresh_huge_page+0x78/0x1a0
alloc_pool_huge_page+0x6f/0xf0
set_max_huge_pages+0x10c/0x250
nr_hugepages_store_common+0x92/0x120
? __kmalloc+0x171/0x270
kernfs_fop_write+0xc1/0x1a0
vfs_write+0xc7/0x1f0
ksys_write+0x5f/0xe0
do_syscall_64+0x4d/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: c64be2bb1c6e ("drivers: add Contiguous Memory Allocator")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Barry Song <song.bao.hua@hisilicon.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200730163123.6451-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a6f23d14ec7d7d02220ad8bb2774be3322b9aeec upstream.
When workload runs in cgroups that aren't directly below root cgroup and
their parent specifies reclaim protection, it may end up ineffective.
The reason is that propagate_protected_usage() is not called in all
hierarchy up. All the protected usage is incorrectly accumulated in the
workload's parent. This means that siblings_low_usage is overestimated
and effective protection underestimated. Even though it is transitional
phenomenon (uncharge path does correct propagation and fixes the wrong
children_low_usage), it can undermine the intended protection
unexpectedly.
We have noticed this problem while seeing a swap out in a descendant of a
protected memcg (intermediate node) while the parent was conveniently
under its protection limit and the memory pressure was external to that
hierarchy. Michal has pinpointed this down to the wrong
siblings_low_usage which led to the unwanted reclaim.
The fix is simply updating children_low_usage in respective ancestors also
in the charging path.
Fixes: 230671533d64 ("mm: memory.low hierarchical behavior")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org> [4.18+]
Link: http://lkml.kernel.org/r/20200803153231.15477-1-mhocko@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4a93025cbe4a0b19d1a25a2d763a3d2018bad0d9 upstream.
Especially with memory hotplug, we can have offline sections (with a
garbage memmap) and overlapping zones. We have to make sure to only touch
initialized memmaps (online sections managed by the buddy) and that the
zone matches, to not move pages between zones.
To test if this can actually happen, I added a simple
BUG_ON(page_zone(page_i) != page_zone(page_j));
right before the swap. When hotplugging a 256M DIMM to a 4G x86-64 VM and
onlining the first memory block "online_movable" and the second memory
block "online_kernel", it will trigger the BUG, as both zones (NORMAL and
MOVABLE) overlap.
This might result in all kinds of weird situations (e.g., double
allocations, list corruptions, unmovable allocations ending up in the
movable zone).
Fixes: e900a918b098 ("mm: shuffle initial free memory to improve memory-side-cache utilization")
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org> [5.2+]
Link: http://lkml.kernel.org/r/20200624094741.9918-2-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 34ae204f18519f0920bd50a644abd6fefc8dbfcf upstream.
Commit c0d0381ade79 ("hugetlbfs: use i_mmap_rwsem for more pmd sharing
synchronization") requires callers of huge_pte_alloc to hold i_mmap_rwsem
in at least read mode. This is because the explicit locking in
huge_pmd_share (called by huge_pte_alloc) was removed. When restructuring
the code, the call to huge_pte_alloc in the else block at the beginning of
hugetlb_fault was missed.
Unfortunately, that else clause is exercised when there is no page table
entry. This will likely lead to a call to huge_pmd_share. If
huge_pmd_share thinks pmd sharing is possible, it will traverse the
mapping tree (i_mmap) without holding i_mmap_rwsem. If someone else is
modifying the tree, bad things such as addressing exceptions or worse
could happen.
Simply remove the else clause. It should have been removed previously.
The code following the else will call huge_pte_alloc with the appropriate
locking.
To prevent this type of issue in the future, add routines to assert that
i_mmap_rwsem is held, and call these routines in huge pmd sharing
routines.
Fixes: c0d0381ade79 ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization")
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A.Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/e670f327-5cf9-1959-96e4-6dc7cc30d3d5@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 18e77600f7a1ed69f8ce46c9e11cad0985712dfa upstream.
Only once have I seen this scenario (and forgot even to notice what forced
the eventual crash): a sequence of "BUG: Bad page map" alerts from
vm_normal_page(), from zap_pte_range() servicing exit_mmap();
pmd:00000000, pte values corresponding to data in physical page 0.
The pte mappings being zapped in this case were supposed to be from a huge
page of ext4 text (but could as well have been shmem): my belief is that
it was racing with collapse_file()'s retract_page_tables(), found *pmd
pointing to a page table, locked it, but *pmd had become 0 by the time
start_pte was decided.
In most cases, that possibility is excluded by holding mmap lock; but
exit_mmap() proceeds without mmap lock. Most of what's run by khugepaged
checks khugepaged_test_exit() after acquiring mmap lock:
khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so,
for example. But retract_page_tables() did not: fix that.
The fix is for retract_page_tables() to check khugepaged_test_exit(),
after acquiring mmap lock, before doing anything to the page table.
Getting the mmap lock serializes with __mmput(), which briefly takes and
drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on
mm_users makes sure we don't touch the page table once exit_mmap() might
reach it, since exit_mmap() will be proceeding without mmap lock, not
expecting anyone to be racing with it.
Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 119a5fc16105b2b9383a6e2a7800b2ef861b2975 upstream.
When retract_page_tables() removes a page table to make way for a huge
pmd, it holds huge page lock, i_mmap_lock_write, mmap_write_trylock and
pmd lock; but when collapse_pte_mapped_thp() does the same (to handle the
case when the original mmap_write_trylock had failed), only
mmap_write_trylock and pmd lock are held.
That's not enough. One machine has twice crashed under load, with "BUG:
spinlock bad magic" and GPF on 6b6b6b6b6b6b6b6b. Examining the second
crash, page_vma_mapped_walk_done()'s spin_unlock of pvmw->ptl (serving
page_referenced() on a file THP, that had found a page table at *pmd)
discovers that the page table page and its lock have already been freed by
the time it comes to unlock.
Follow the example of retract_page_tables(), but we only need one of huge
page lock or i_mmap_lock_write to secure against this: because it's the
narrower lock, and because it simplifies collapse_pte_mapped_thp() to know
the hpage earlier, choose to rely on huge page lock here.
Fixes: 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021213070.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 75802ca66354a39ab8e35822747cd08b3384a99a upstream.
This is found by code observation only.
Firstly, the worst case scenario should assume the whole range was covered
by pmd sharing. The old algorithm might not work as expected for ranges
like (1g-2m, 1g+2m), where the adjusted range should be (0, 1g+2m) but the
expected range should be (0, 2g).
Since at it, remove the loop since it should not be required. With that,
the new code should be faster too when the invalidating range is huge.
Mike said:
: With range (1g-2m, 1g+2m) within a vma (0, 2g) the existing code will only
: adjust to (0, 1g+2m) which is incorrect.
:
: We should cc stable. The original reason for adjusting the range was to
: prevent data corruption (getting wrong page). Since the range is not
: always adjusted correctly, the potential for corruption still exists.
:
: However, I am fairly confident that adjust_range_if_pmd_sharing_possible
: is only gong to be called in two cases:
:
: 1) for a single page
: 2) for range == entire vma
:
: In those cases, the current code should produce the correct results.
:
: To be safe, let's just cc stable.
Fixes: 017b1660df89 ("mm: migration: fix migration of huge PMD shared pages")
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200730201636.74778-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 723a80dafed5c95889d48baab9aa433a6ffa0b4e upstream.
pmdp_collapse_flush() should be given the start address at which the huge
page is mapped, haddr: it was given addr, which at that point has been
used as a local variable, incremented to the end address of the extent.
Found by source inspection while chasing a hugepage locking bug, which I
then could not explain by this. At first I thought this was very bad;
then saw that all of the page translations that were not flushed would
actually still point to the right pages afterwards, so harmless; then
realized that I know nothing of how different architectures and models
cache intermediate paging structures, so maybe it matters after all -
particularly since the page table concerned is immediately freed.
Much easier to fix than to think about.
Fixes: 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021204390.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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empty zone"
commit a8a4b7aeaf841311cb13ff0f6c4710c7a00e68d4 upstream.
This reverts commit 26e7deadaae175.
Sonny reported that one of their tests started failing on the latest
kernel on their Chrome OS platform. The root cause is that the above
commit removed the protection line of empty zone, while the parser used in
the test relies on the protection line to mark the end of each zone.
Let's revert it to avoid breaking userspace testing or applications.
Fixes: 26e7deadaae175 ("mm/vmstat.c: do not show lowmem reserve protection information of empty zone)"
Reported-by: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org> [5.8.x]
Link: http://lkml.kernel.org/r/20200811075412.12872-1-bhe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 0a3b3c253a1eb2c7fe7f34086d46660c909abeb3 ]
A large process running on a heavily loaded system can encounter the
following RCU CPU stall warning:
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 3-....: (20998 ticks this GP) idle=4ea/1/0x4000000000000002 softirq=556558/556558 fqs=5190
(t=21013 jiffies g=1005461 q=132576)
NMI backtrace for cpu 3
CPU: 3 PID: 501900 Comm: aio-free-ring-w Kdump: loaded Not tainted 5.2.9-108_fbk12_rc3_3858_gb83b75af7909 #1
Hardware name: Wiwynn HoneyBadger/PantherPlus, BIOS HBM6.71 02/03/2016
Call Trace:
<IRQ>
dump_stack+0x46/0x60
nmi_cpu_backtrace.cold.3+0x13/0x50
? lapic_can_unplug_cpu.cold.27+0x34/0x34
nmi_trigger_cpumask_backtrace+0xba/0xca
rcu_dump_cpu_stacks+0x99/0xc7
rcu_sched_clock_irq.cold.87+0x1aa/0x397
? tick_sched_do_timer+0x60/0x60
update_process_times+0x28/0x60
tick_sched_timer+0x37/0x70
__hrtimer_run_queues+0xfe/0x270
hrtimer_interrupt+0xf4/0x210
smp_apic_timer_interrupt+0x5e/0x120
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:kmem_cache_free+0x223/0x300
Code: 88 00 00 00 0f 85 ca 00 00 00 41 8b 55 18 31 f6 f7 da 41 f6 45 0a 02 40 0f 94 c6 83 c6 05 9c 41 5e fa e8 a0 a7 01 00 41 56 9d <49> 8b 47 08 a8 03 0f 85 87 00 00 00 65 48 ff 08 e9 3d fe ff ff 65
RSP: 0018:ffffc9000e8e3da8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000020000 RBX: ffff88861b9de960 RCX: 0000000000000030
RDX: fffffffffffe41e8 RSI: 000060777fe3a100 RDI: 000000000001be18
RBP: ffffea00186e7780 R08: ffffffffffffffff R09: ffffffffffffffff
R10: ffff88861b9dea28 R11: ffff88887ffde000 R12: ffffffff81230a1f
R13: ffff888854684dc0 R14: 0000000000000206 R15: ffff8888547dbc00
? remove_vma+0x4f/0x60
remove_vma+0x4f/0x60
exit_mmap+0xd6/0x160
mmput+0x4a/0x110
do_exit+0x278/0xae0
? syscall_trace_enter+0x1d3/0x2b0
? handle_mm_fault+0xaa/0x1c0
do_group_exit+0x3a/0xa0
__x64_sys_exit_group+0x14/0x20
do_syscall_64+0x42/0x100
entry_SYSCALL_64_after_hwframe+0x44/0xa9
And on a PREEMPT=n kernel, the "while (vma)" loop in exit_mmap() can run
for a very long time given a large process. This commit therefore adds
a cond_resched() to this loop, providing RCU any needed quiescent states.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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khugepaged has to drop mmap lock several times while collapsing a page.
The situation can change while the lock is dropped and we need to
re-validate that the VMA is still in place and the PMD is still subject
for collapse.
But we miss one corner case: while collapsing an anonymous pages the VMA
could be replaced with file VMA. If the file VMA doesn't have any
private pages we get NULL pointer dereference:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
anon_vma_lock_write include/linux/rmap.h:120 [inline]
collapse_huge_page mm/khugepaged.c:1110 [inline]
khugepaged_scan_pmd mm/khugepaged.c:1349 [inline]
khugepaged_scan_mm_slot mm/khugepaged.c:2110 [inline]
khugepaged_do_scan mm/khugepaged.c:2193 [inline]
khugepaged+0x3bba/0x5a10 mm/khugepaged.c:2238
The fix is to make sure that the VMA is anonymous in
hugepage_vma_revalidate(). The helper is only used for collapsing
anonymous pages.
Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Reported-by: syzbot+ed318e8b790ca72c5ad0@syzkaller.appspotmail.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200722121439.44328-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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hugetlb_cma[0] can be NULL due to various reasons, for example, node0
has no memory. so NULL hugetlb_cma[0] doesn't necessarily mean cma is
not enabled. gigantic pages might have been reserved on other nodes.
This patch fixes possible double reservation and CMA leak.
[akpm@linux-foundation.org: fix CONFIG_CMA=n warning]
[sfr@canb.auug.org.au: better checks before using hugetlb_cma]
Link: http://lkml.kernel.org/r/20200721205716.6dbaa56b@canb.auug.org.au
Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200710005726.36068-1-song.bao.hua@hisilicon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If the kmem_cache refcount is greater than one, we should not mark the
root kmem_cache as dying. If we mark the root kmem_cache dying
incorrectly, the non-root kmem_cache can never be destroyed. It
resulted in memory leak when memcg was destroyed. We can use the
following steps to reproduce.
1) Use kmem_cache_create() to create a new kmem_cache named A.
2) Coincidentally, the kmem_cache A is an alias for kmem_cache B,
so the refcount of B is just increased.
3) Use kmem_cache_destroy() to destroy the kmem_cache A, just
decrease the B's refcount but mark the B as dying.
4) Create a new memory cgroup and alloc memory from the kmem_cache
B. It leads to create a non-root kmem_cache for allocating memory.
5) When destroy the memory cgroup created in the step 4), the
non-root kmem_cache can never be destroyed.
If we repeat steps 4) and 5), this will cause a lot of memory leak. So
only when refcount reach zero, we mark the root kmem_cache as dying.
Fixes: 92ee383f6daa ("mm: fix race between kmem_cache destroy, create and deactivate")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200716165103.83462-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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It was hard to keep a test running, moving tasks between memcgs with
move_charge_at_immigrate, while swapping: mem_cgroup_id_get_many()'s
refcount is discovered to be 0 (supposedly impossible), so it is then
forced to REFCOUNT_SATURATED, and after thousands of warnings in quick
succession, the test is at last put out of misery by being OOM killed.
This is because of the way moved_swap accounting was saved up until the
task move gets completed in __mem_cgroup_clear_mc(), deferred from when
mem_cgroup_move_swap_account() actually exchanged old and new ids.
Concurrent activity can free up swap quicker than the task is scanned,
bringing id refcount down 0 (which should only be possible when
offlining).
Just skip that optimization: do that part of the accounting immediately.
Fixes: 615d66c37c75 ("mm: memcontrol: fix memcg id ref counter on swap charge move")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2007071431050.4726@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Prabhakar reported an OOPS inside mem_cgroup_get_nr_swap_pages()
function in a corner case seen on some arm64 boards when kdump kernel
runs with "cgroup_disable=memory" passed to the kdump kernel via
bootargs.
The root-cause behind the same is that currently mem_cgroup_swap_init()
function is implemented as a subsys_initcall() call instead of a
core_initcall(), this means 'cgroup_memory_noswap' still remains set to
the default value (false) even when memcg is disabled via
"cgroup_disable=memory" boot parameter.
This may result in premature OOPS inside mem_cgroup_get_nr_swap_pages()
function in corner cases:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
[0000000000000188] user address but active_mm is swapper
Internal error: Oops: 96000006 [#1] SMP
Modules linked in:
<..snip..>
Call trace:
mem_cgroup_get_nr_swap_pages+0x9c/0xf4
shrink_lruvec+0x404/0x4f8
shrink_node+0x1a8/0x688
do_try_to_free_pages+0xe8/0x448
try_to_free_pages+0x110/0x230
__alloc_pages_slowpath.constprop.106+0x2b8/0xb48
__alloc_pages_nodemask+0x2ac/0x2f8
alloc_page_interleave+0x20/0x90
alloc_pages_current+0xdc/0xf8
atomic_pool_expand+0x60/0x210
__dma_atomic_pool_init+0x50/0xa4
dma_atomic_pool_init+0xac/0x158
do_one_initcall+0x50/0x218
kernel_init_freeable+0x22c/0x2d0
kernel_init+0x18/0x110
ret_from_fork+0x10/0x18
Code: aa1403e3 91106000 97f82a27 14000011 (f940c663)
---[ end trace 9795948475817de4 ]---
Kernel panic - not syncing: Fatal exception
Rebooting in 10 seconds..
Fixes: eccb52e78809 ("mm: memcontrol: prepare swap controller setup for integration")
Reported-by: Prabhakar Kushwaha <pkushwaha@marvell.com>
Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: James Morse <james.morse@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: http://lkml.kernel.org/r/1593641660-13254-2-git-send-email-bhsharma@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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clang static analysis reports a garbage return
In file included from mm/memory.c:84:
mm/memory.c:1612:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn]
return err;
^~~~~~~~~~
The setting of err depends on a loop executing. So initialize err.
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200703155354.29132-1-trix@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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After commit fdc85222d58e ("kernfs: kvmalloc xattr value instead of
kmalloc"), simple xattr entry is allocated with kvmalloc() instead of
kmalloc(), so we should release it with kvfree() instead of kfree().
Fixes: fdc85222d58e ("kernfs: kvmalloc xattr value instead of kmalloc")
Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Daniel Xu <dxu@dxuuu.xyz>
Cc: Chris Down <chris@chrisdown.name>
Cc: Andreas Dilger <adilger@dilger.ca>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org> [5.7]
Link: http://lkml.kernel.org/r/20200704051608.15043-1-cgxu519@mykernel.net
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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VMA with VM_GROWSDOWN or VM_GROWSUP flag set can change their size under
mmap_read_lock(). It can lead to race with __do_munmap():
Thread A Thread B
__do_munmap()
detach_vmas_to_be_unmapped()
mmap_write_downgrade()
expand_downwards()
vma->vm_start = address;
// The VMA now overlaps with
// VMAs detached by the Thread A
// page fault populates expanded part
// of the VMA
unmap_region()
// Zaps pagetables partly
// populated by Thread B
Similar race exists for expand_upwards().
The fix is to avoid downgrading mmap_lock in __do_munmap() if detached
VMAs are next to VM_GROWSDOWN or VM_GROWSUP VMA.
[akpm@linux-foundation.org: s/mmap_sem/mmap_lock/ in comment]
Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org> [4.20+]
Link: http://lkml.kernel.org/r/20200709105309.42495-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Naresh Kamboju reported that the LTP tests can cause warnings on i386
going back all the way to v5.0, and bisected it to commit 2c91bd4a4e2e
("mm: speed up mremap by 20x on large regions").
The warning in move_normal_pmd() is actually mostly correct, but we have
a very unusual special case at process creation time, when we may move
the stack down with an overlapping mode (kind of like a "memmove()"
except using the page tables).
And when you have just the right condition of "move a large initial
stack by the right alignment in the end, but with the early part of the
move being only page-aligned", we'll be in a situation where we're
trying to move a normal PMD entry on top of an already existing - but
now empty - PMD entry.
The warning is still worth having, in case it ever triggers other cases,
and perhaps as a reminder that we could do the stack move case more
efficiently (although it's clearly rare enough that it probably doesn't
matter).
But make it do WARN_ON_ONCE(), so that you can't flood the logs with it.
And add a *big* comment above it to explain and remind us what's going
on, because it took some figuring out to see how this could trigger.
Kudos to Joel Fernandes for debugging this.
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Debugged-and-acked-by: Joel Fernandes <joel@joelfernandes.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 fixes from Andreas Gruenbacher:
"Fix gfs2 readahead deadlocks by adding a IOCB_NOIO flag that allows
gfs2 to use the generic fiel read iterator functions without having to
worry about being called back while holding locks".
* tag 'gfs2-v5.8-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Rework read and page fault locking
fs: Add IOCB_NOIO flag for generic_file_read_iter
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I realize that we fairly recently raised it to 4.8, but the fact is, 4.9
is a much better minimum version to target.
We have a number of workarounds for actual bugs in pre-4.9 gcc versions
(including things like internal compiler errors on ARM), but we also
have some syntactic workarounds for lacking features.
In particular, raising the minimum to 4.9 means that we can now just
assume _Generic() exists, which is likely the much better replacement
for a lot of very convoluted built-time magic with conditionals on
sizeof and/or __builtin_choose_expr() with same_type() etc.
Using _Generic also means that you will need to have a very recent
version of 'sparse', but thats easy to build yourself, and much less of
a hassle than some old gcc version can be.
The latest (in a long string) of reasons for minimum compiler version
upgrades was commit 5435f73d5c4a ("efi/x86: Fix build with gcc 4").
Ard points out that RHEL 7 uses gcc-4.8, but the people who stay back on
old RHEL versions persumably also don't build their own kernels anyway.
And maybe they should cross-built or just have a little side affair with
a newer compiler?
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add an IOCB_NOIO flag that indicates to generic_file_read_iter that it
shouldn't trigger any filesystem I/O for the actual request or for
readahead. This allows to do tentative reads out of the page cache as
some filesystems allow, and to take the appropriate locks and retry the
reads only if the requested pages are not cached.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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When I increased the upper bound of the min_free_kbytes value in
ee8eb9a5fe863 ("mm/page_alloc: increase default min_free_kbytes bound") I
forgot to tweak the above comment to reflect the new value. This patch
fixes that mistake.
Signed-off-by: Joel Savitz <jsavitz@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Fabrizio D'Angelo <fdangelo@redhat.com>
Link: http://lkml.kernel.org/r/20200624221236.29560-1-jsavitz@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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