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commit 2f5841349df281ecf8f81cc82d869b8476f0db0b upstream.
A cast to 'time_t' was accidentally left in place during the
conversion of __do_adjtimex() to 64-bit timestamps, so the
resulting value is incorrectly truncated.
Remove the cast so the 64-bit time gets propagated correctly.
Fixes: ead25417f82e ("timex: use __kernel_timex internally")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20191108203435.112759-2-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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ptrace_stop()
commit 937c6b27c73e02cd4114f95f5c37ba2c29fadba1 upstream.
ptrace_stop() does preempt_enable_no_resched() to avoid the preemption,
but after that cgroup_enter_frozen() does spin_lock/unlock and this adds
another preemption point.
Reported-and-tested-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 731dc9df975a5da21237a18c3384f811a7a41cc6 upstream.
A kernel module may need to check the value of the "mitigations=" kernel
command line parameter as part of its setup when the module needs
to perform software mitigations for a CPU flaw.
Uninline and export the helper functions surrounding the cpu_mitigations
enum to allow for their usage from a module.
Lastly, privatize the enum and cpu_mitigations variable since the value of
cpu_mitigations can be checked with the exported helper functions.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 52338415cf4d4064ae6b8dd972dadbda841da4fa ]
The update of the VDSO data is depending on __arch_use_vsyscall() returning
True. This is a leftover from the attempt to map the features of various
architectures 1:1 into generic code.
The usage of __arch_use_vsyscall() in the actual vsyscall implementations
got dropped and replaced by the requirement for the architecture code to
return U64_MAX if the global clocksource is not usable in the VDSO.
But the __arch_use_vsyscall() check in the update code stayed which causes
the VDSO data to be stale or invalid when an architecture actually
implements that function and returns False when the current clocksource is
not usable in the VDSO.
As a consequence the VDSO implementations of clock_getres(), time(),
clock_gettime(CLOCK_.*_COARSE) operate on invalid data and return bogus
information.
Remove the __arch_use_vsyscall() check from the VDSO update function and
update the VDSO data unconditionally.
[ tglx: Massaged changelog and removed the now useless implementations in
asm-generic/ARM64/MIPS ]
Fixes: 44f57d788e7deecb50 ("timekeeping: Provide a generic update_vsyscall() implementation")
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1571887709-11447-1-git-send-email-chenhc@lemote.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e284df705cf1eeedb5ec3a66ed82d17a64659150 ]
While the static key is correctly initialized as being disabled, it will
remain forever enabled once turned on. This means that if we start with an
asymmetric system and hotplug out enough CPUs to end up with an SMP system,
the static key will remain set - which is obviously wrong. We should detect
this and turn off things like misfit migration and capacity aware wakeups.
As Quentin pointed out, having separate root domains makes this slightly
trickier. We could have exclusive cpusets that create an SMP island - IOW,
the domains within this root domain will not see any asymmetry. This means
we can't just disable the key on domain destruction, we need to count how
many asymmetric root domains we have.
Consider the following example using Juno r0 which is 2+4 big.LITTLE, where
two identical cpusets are created: they both span both big and LITTLE CPUs:
asym0 asym1
[ ][ ]
L L B L L B
$ cgcreate -g cpuset:asym0
$ cgset -r cpuset.cpus=0,1,3 asym0
$ cgset -r cpuset.mems=0 asym0
$ cgset -r cpuset.cpu_exclusive=1 asym0
$ cgcreate -g cpuset:asym1
$ cgset -r cpuset.cpus=2,4,5 asym1
$ cgset -r cpuset.mems=0 asym1
$ cgset -r cpuset.cpu_exclusive=1 asym1
$ cgset -r cpuset.sched_load_balance=0 .
(the CPU numbering may look odd because on the Juno LITTLEs are CPUs 0,3-5
and bigs are CPUs 1-2)
If we make one of those SMP (IOW remove asymmetry) by e.g. hotplugging its
big core, we would end up with an SMP cpuset and an asymmetric cpuset - the
static key must remain set, because we still have one asymmetric root domain.
With the above example, this could be done with:
$ echo 0 > /sys/devices/system/cpu/cpu2/online
Which would result in:
asym0 asym1
[ ][ ]
L L B L L
When both SMP and asymmetric cpusets are present, all CPUs will observe
sched_asym_cpucapacity being set (it is system-wide), but not all CPUs
observe asymmetry in their sched domain hierarchy:
per_cpu(sd_asym_cpucapacity, <any CPU in asym0>) == <some SD at DIE level>
per_cpu(sd_asym_cpucapacity, <any CPU in asym1>) == NULL
Change the simple key enablement to an increment, and decrement the key
counter when destroying domains that cover asymmetric CPUs.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Dietmar.Eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hannes@cmpxchg.org
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: qperret@google.com
Cc: tj@kernel.org
Cc: vincent.guittot@linaro.org
Fixes: df054e8445a4 ("sched/topology: Add static_key for asymmetric CPU capacity optimizations")
Link: https://lkml.kernel.org/r/20191023153745.19515-3-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit cd1cb3350561d2bf544ddfef76fbf0b1c9c7178f ]
Turns out hotplugging CPUs that are in exclusive cpusets can lead to the
cpuset code feeding empty cpumasks to the sched domain rebuild machinery.
This leads to the following splat:
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 235 Comm: kworker/5:2 Not tainted 5.4.0-rc1-00005-g8d495477d62e #23
Hardware name: ARM Juno development board (r0) (DT)
Workqueue: events cpuset_hotplug_workfn
pstate: 60000005 (nZCv daif -PAN -UAO)
pc : build_sched_domains (./include/linux/arch_topology.h:23 kernel/sched/topology.c:1898 kernel/sched/topology.c:1969)
lr : build_sched_domains (kernel/sched/topology.c:1966)
Call trace:
build_sched_domains (./include/linux/arch_topology.h:23 kernel/sched/topology.c:1898 kernel/sched/topology.c:1969)
partition_sched_domains_locked (kernel/sched/topology.c:2250)
rebuild_sched_domains_locked (./include/linux/bitmap.h:370 ./include/linux/cpumask.h:538 kernel/cgroup/cpuset.c:955 kernel/cgroup/cpuset.c:978 kernel/cgroup/cpuset.c:1019)
rebuild_sched_domains (kernel/cgroup/cpuset.c:1032)
cpuset_hotplug_workfn (kernel/cgroup/cpuset.c:3205 (discriminator 2))
process_one_work (./arch/arm64/include/asm/jump_label.h:21 ./include/linux/jump_label.h:200 ./include/trace/events/workqueue.h:114 kernel/workqueue.c:2274)
worker_thread (./include/linux/compiler.h:199 ./include/linux/list.h:268 kernel/workqueue.c:2416)
kthread (kernel/kthread.c:255)
ret_from_fork (arch/arm64/kernel/entry.S:1167)
Code: f860dae2 912802d6 aa1603e1 12800000 (f8616853)
The faulty line in question is:
cap = arch_scale_cpu_capacity(cpumask_first(cpu_map));
and we're not checking the return value against nr_cpu_ids (we shouldn't
have to!), which leads to the above.
Prevent generate_sched_domains() from returning empty cpumasks, and add
some assertion in build_sched_domains() to scream bloody murder if it
happens again.
The above splat was obtained on my Juno r0 with the following reproducer:
$ cgcreate -g cpuset:asym
$ cgset -r cpuset.cpus=0-3 asym
$ cgset -r cpuset.mems=0 asym
$ cgset -r cpuset.cpu_exclusive=1 asym
$ cgcreate -g cpuset:smp
$ cgset -r cpuset.cpus=4-5 smp
$ cgset -r cpuset.mems=0 smp
$ cgset -r cpuset.cpu_exclusive=1 smp
$ cgset -r cpuset.sched_load_balance=0 .
$ echo 0 > /sys/devices/system/cpu/cpu4/online
$ echo 0 > /sys/devices/system/cpu/cpu5/online
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar.Eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hannes@cmpxchg.org
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: qperret@google.com
Cc: tj@kernel.org
Cc: vincent.guittot@linaro.org
Fixes: 05484e098448 ("sched/topology: Add SD_ASYM_CPUCAPACITY flag detection")
Link: https://lkml.kernel.org/r/20191023153745.19515-2-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 3b4d9eb2ee74dd5ea7fa36cffb0ca7f5bc4924da ]
There is one more problematic case I noticed while recently fixing BPF kallsyms
handling in cd7455f1013e ("bpf: Fix use after free in subprog's jited symbol
removal") and that is bpf_get_prog_name().
If BTF has been attached to the prog, then we may be able to fetch the function
signature type id in kallsyms through prog->aux->func_info[prog->aux->func_idx].type_id.
However, while the BTF object itself is torn down via RCU callback, the prog's
aux->func_info is immediately freed via kvfree(prog->aux->func_info) once the
prog's refcount either hit zero or when subprograms were already exposed via
kallsyms and we hit the error path added in 5482e9a93c83 ("bpf: Fix memleak in
aux->func_info and aux->btf").
This violates RCU as well since kallsyms could be walked in parallel where we
could access aux->func_info. Hence, defer kvfree() to after RCU grace period.
Looking at ba64e7d85252 ("bpf: btf: support proper non-jit func info") there
is no reason/dependency where we couldn't defer the kvfree(aux->func_info) into
the RCU callback.
Fixes: 5482e9a93c83 ("bpf: Fix memleak in aux->func_info and aux->btf")
Fixes: ba64e7d85252 ("bpf: btf: support proper non-jit func info")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/875f2906a7c1a0691f2d567b4d8e4ea2739b1e88.1571779205.git.daniel@iogearbox.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit cd7455f1013ef96d5cbf5c05d2b7c06f273810a6 ]
syzkaller managed to trigger the following crash:
[...]
BUG: unable to handle page fault for address: ffffc90001923030
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD aa551067 P4D aa551067 PUD aa552067 PMD a572b067 PTE 80000000a1173163
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 7982 Comm: syz-executor912 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bpf_jit_binary_hdr include/linux/filter.h:787 [inline]
RIP: 0010:bpf_get_prog_addr_region kernel/bpf/core.c:531 [inline]
RIP: 0010:bpf_tree_comp kernel/bpf/core.c:600 [inline]
RIP: 0010:__lt_find include/linux/rbtree_latch.h:115 [inline]
RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:208 [inline]
RIP: 0010:bpf_prog_kallsyms_find kernel/bpf/core.c:674 [inline]
RIP: 0010:is_bpf_text_address+0x184/0x3b0 kernel/bpf/core.c:709
[...]
Call Trace:
kernel_text_address kernel/extable.c:147 [inline]
__kernel_text_address+0x9a/0x110 kernel/extable.c:102
unwind_get_return_address+0x4c/0x90 arch/x86/kernel/unwind_frame.c:19
arch_stack_walk+0x98/0xe0 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0xb6/0x150 kernel/stacktrace.c:123
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:510
kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:518
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc mm/slab.c:3319 [inline]
kmem_cache_alloc+0x1f5/0x2e0 mm/slab.c:3483
getname_flags+0xba/0x640 fs/namei.c:138
getname+0x19/0x20 fs/namei.c:209
do_sys_open+0x261/0x560 fs/open.c:1091
__do_sys_open fs/open.c:1115 [inline]
__se_sys_open fs/open.c:1110 [inline]
__x64_sys_open+0x87/0x90 fs/open.c:1110
do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
[...]
After further debugging it turns out that we walk kallsyms while in parallel
we tear down a BPF program which contains subprograms that have been JITed
though the program itself has not been fully exposed and is eventually bailing
out with error.
The bpf_prog_kallsyms_del_subprogs() in bpf_prog_load()'s error path removes
the symbols, however, bpf_prog_free() tears down the JIT memory too early via
scheduled work. Instead, it needs to properly respect RCU grace period as the
kallsyms walk for BPF is under RCU.
Fix it by refactoring __bpf_prog_put()'s tear down and reuse it in our error
path where we defer final destruction when we have subprogs in the program.
Fixes: 7d1982b4e335 ("bpf: fix panic in prog load calls cleanup")
Fixes: 1c2a088a6626 ("bpf: x64: add JIT support for multi-function programs")
Reported-by: syzbot+710043c5d1d5b5013bc7@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: syzbot+710043c5d1d5b5013bc7@syzkaller.appspotmail.com
Link: https://lore.kernel.org/bpf/55f6367324c2d7e9583fa9ccf5385dcbba0d7a6e.1571752452.git.daniel@iogearbox.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit fa729c4df558936b4a1a7b3e2234011f44ede28b upstream.
Validate the stack arguments and setup the stack depening on whether or not
it is growing down or up.
Legacy clone() required userspace to know in which direction the stack is
growing and pass down the stack pointer appropriately. To make things more
confusing microblaze uses a variant of the clone() syscall selected by
CONFIG_CLONE_BACKWARDS3 that takes an additional stack_size argument.
IA64 has a separate clone2() syscall which also takes an additional
stack_size argument. Finally, parisc has a stack that is growing upwards.
Userspace therefore has a lot nasty code like the following:
#define __STACK_SIZE (8 * 1024 * 1024)
pid_t sys_clone(int (*fn)(void *), void *arg, int flags, int *pidfd)
{
pid_t ret;
void *stack;
stack = malloc(__STACK_SIZE);
if (!stack)
return -ENOMEM;
#ifdef __ia64__
ret = __clone2(fn, stack, __STACK_SIZE, flags | SIGCHLD, arg, pidfd);
#elif defined(__parisc__) /* stack grows up */
ret = clone(fn, stack, flags | SIGCHLD, arg, pidfd);
#else
ret = clone(fn, stack + __STACK_SIZE, flags | SIGCHLD, arg, pidfd);
#endif
return ret;
}
or even crazier variants such as [3].
With clone3() we have the ability to validate the stack. We can check that
when stack_size is passed, the stack pointer is valid and the other way
around. We can also check that the memory area userspace gave us is fine to
use via access_ok(). Furthermore, we probably should not require
userspace to know in which direction the stack is growing. It is easy
for us to do this in the kernel and I couldn't find the original
reasoning behind exposing this detail to userspace.
/* Intentional user visible API change */
clone3() was released with 5.3. Currently, it is not documented and very
unclear to userspace how the stack and stack_size argument have to be
passed. After talking to glibc folks we concluded that trying to change
clone3() to setup the stack instead of requiring userspace to do this is
the right course of action.
Note, that this is an explicit change in user visible behavior we introduce
with this patch. If it breaks someone's use-case we will revert! (And then
e.g. place the new behavior under an appropriate flag.)
Breaking someone's use-case is very unlikely though. First, neither glibc
nor musl currently expose a wrapper for clone3(). Second, there is no real
motivation for anyone to use clone3() directly since it does not provide
features that legacy clone doesn't. New features for clone3() will first
happen in v5.5 which is why v5.4 is still a good time to try and make that
change now and backport it to v5.3. Searches on [4] did not reveal any
packages calling clone3().
[1]: https://lore.kernel.org/r/CAG48ez3q=BeNcuVTKBN79kJui4vC6nw0Bfq6xc-i0neheT17TA@mail.gmail.com
[2]: https://lore.kernel.org/r/20191028172143.4vnnjpdljfnexaq5@wittgenstein
[3]: https://github.com/systemd/systemd/blob/5238e9575906297608ff802a27e2ff9effa3b338/src/basic/raw-clone.h#L31
[4]: https://codesearch.debian.net
Fixes: 7f192e3cd316 ("fork: add clone3")
Cc: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-api@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # 5.3
Cc: GNU C Library <libc-alpha@sourceware.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20191031113608.20713-1-christian.brauner@ubuntu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 9fa8c9c647be624e91b09ecffa7cd97ee0600b40 ]
In the format of synthetic events, the "gfp_t" is shown as "signed:1",
but in fact the "gfp_t" is "unsigned", should be shown as "signed:0".
The issue can be reproduced by the following commands:
echo 'memlatency u64 lat; unsigned int order; gfp_t gfp_flags; int migratetype' > /sys/kernel/debug/tracing/synthetic_events
cat /sys/kernel/debug/tracing/events/synthetic/memlatency/format
name: memlatency
ID: 2233
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:u64 lat; offset:8; size:8; signed:0;
field:unsigned int order; offset:16; size:4; signed:0;
field:gfp_t gfp_flags; offset:24; size:4; signed:1;
field:int migratetype; offset:32; size:4; signed:1;
print fmt: "lat=%llu, order=%u, gfp_flags=%x, migratetype=%d", REC->lat, REC->order, REC->gfp_flags, REC->migratetype
Link: http://lkml.kernel.org/r/20191018012034.6404-1-zhengjun.xing@linux.intel.com
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 763a9ec06c409dcde2a761aac4bb83ff3938e0b3 ]
Commit:
de53fd7aedb1 ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")
introduced a few compilation warnings:
kernel/sched/fair.c: In function '__refill_cfs_bandwidth_runtime':
kernel/sched/fair.c:4365:6: warning: variable 'now' set but not used [-Wunused-but-set-variable]
kernel/sched/fair.c: In function 'start_cfs_bandwidth':
kernel/sched/fair.c:4992:6: warning: variable 'overrun' set but not used [-Wunused-but-set-variable]
Also, __refill_cfs_bandwidth_runtime() does no longer update the
expiration time, so fix the comments accordingly.
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Dave Chiluk <chiluk+linux@indeed.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: pauld@redhat.com
Fixes: de53fd7aedb1 ("sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices")
Link: https://lkml.kernel.org/r/1566326455-8038-1-git-send-email-cai@lca.pw
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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cpu-local slices
commit de53fd7aedb100f03e5d2231cfce0e4993282425 upstream.
It has been observed, that highly-threaded, non-cpu-bound applications
running under cpu.cfs_quota_us constraints can hit a high percentage of
periods throttled while simultaneously not consuming the allocated
amount of quota. This use case is typical of user-interactive non-cpu
bound applications, such as those running in kubernetes or mesos when
run on multiple cpu cores.
This has been root caused to cpu-local run queue being allocated per cpu
bandwidth slices, and then not fully using that slice within the period.
At which point the slice and quota expires. This expiration of unused
slice results in applications not being able to utilize the quota for
which they are allocated.
The non-expiration of per-cpu slices was recently fixed by
'commit 512ac999d275 ("sched/fair: Fix bandwidth timer clock drift
condition")'. Prior to that it appears that this had been broken since
at least 'commit 51f2176d74ac ("sched/fair: Fix unlocked reads of some
cfs_b->quota/period")' which was introduced in v3.16-rc1 in 2014. That
added the following conditional which resulted in slices never being
expired.
if (cfs_rq->runtime_expires != cfs_b->runtime_expires) {
/* extend local deadline, drift is bounded above by 2 ticks */
cfs_rq->runtime_expires += TICK_NSEC;
Because this was broken for nearly 5 years, and has recently been fixed
and is now being noticed by many users running kubernetes
(https://github.com/kubernetes/kubernetes/issues/67577) it is my opinion
that the mechanisms around expiring runtime should be removed
altogether.
This allows quota already allocated to per-cpu run-queues to live longer
than the period boundary. This allows threads on runqueues that do not
use much CPU to continue to use their remaining slice over a longer
period of time than cpu.cfs_period_us. However, this helps prevent the
above condition of hitting throttling while also not fully utilizing
your cpu quota.
This theoretically allows a machine to use slightly more than its
allotted quota in some periods. This overflow would be bounded by the
remaining quota left on each per-cpu runqueueu. This is typically no
more than min_cfs_rq_runtime=1ms per cpu. For CPU bound tasks this will
change nothing, as they should theoretically fully utilize all of their
quota in each period. For user-interactive tasks as described above this
provides a much better user/application experience as their cpu
utilization will more closely match the amount they requested when they
hit throttling. This means that cpu limits no longer strictly apply per
period for non-cpu bound applications, but that they are still accurate
over longer timeframes.
This greatly improves performance of high-thread-count, non-cpu bound
applications with low cfs_quota_us allocation on high-core-count
machines. In the case of an artificial testcase (10ms/100ms of quota on
80 CPU machine), this commit resulted in almost 30x performance
improvement, while still maintaining correct cpu quota restrictions.
That testcase is available at https://github.com/indeedeng/fibtest.
Fixes: 512ac999d275 ("sched/fair: Fix bandwidth timer clock drift condition")
Signed-off-by: Dave Chiluk <chiluk+linux@indeed.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Hammond <jhammond@indeed.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kyle Anderson <kwa@yelp.com>
Cc: Gabriel Munos <gmunoz@netflix.com>
Cc: Peter Oskolkov <posk@posk.io>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Brendan Gregg <bgregg@netflix.com>
Link: https://lkml.kernel.org/r/1563900266-19734-2-git-send-email-chiluk+linux@indeed.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5e6c3c7b1ec217c1c4c95d9148182302b9969b97 ]
The following commit from the v5.4 merge window:
d44248a41337 ("perf/core: Rework memory accounting in perf_mmap()")
... breaks auxiliary trace buffer tracking.
If I run command 'perf record -e rbd000' to record samples and saving
them in the **auxiliary** trace buffer then the value of 'locked_vm' becomes
negative after all trace buffers have been allocated and released:
During allocation the values increase:
[52.250027] perf_mmap user->locked_vm:0x87 pinned_vm:0x0 ret:0
[52.250115] perf_mmap user->locked_vm:0x107 pinned_vm:0x0 ret:0
[52.250251] perf_mmap user->locked_vm:0x188 pinned_vm:0x0 ret:0
[52.250326] perf_mmap user->locked_vm:0x208 pinned_vm:0x0 ret:0
[52.250441] perf_mmap user->locked_vm:0x289 pinned_vm:0x0 ret:0
[52.250498] perf_mmap user->locked_vm:0x309 pinned_vm:0x0 ret:0
[52.250613] perf_mmap user->locked_vm:0x38a pinned_vm:0x0 ret:0
[52.250715] perf_mmap user->locked_vm:0x408 pinned_vm:0x2 ret:0
[52.250834] perf_mmap user->locked_vm:0x408 pinned_vm:0x83 ret:0
[52.250915] perf_mmap user->locked_vm:0x408 pinned_vm:0x103 ret:0
[52.251061] perf_mmap user->locked_vm:0x408 pinned_vm:0x184 ret:0
[52.251146] perf_mmap user->locked_vm:0x408 pinned_vm:0x204 ret:0
[52.251299] perf_mmap user->locked_vm:0x408 pinned_vm:0x285 ret:0
[52.251383] perf_mmap user->locked_vm:0x408 pinned_vm:0x305 ret:0
[52.251544] perf_mmap user->locked_vm:0x408 pinned_vm:0x386 ret:0
[52.251634] perf_mmap user->locked_vm:0x408 pinned_vm:0x406 ret:0
[52.253018] perf_mmap user->locked_vm:0x408 pinned_vm:0x487 ret:0
[52.253197] perf_mmap user->locked_vm:0x408 pinned_vm:0x508 ret:0
[52.253374] perf_mmap user->locked_vm:0x408 pinned_vm:0x589 ret:0
[52.253550] perf_mmap user->locked_vm:0x408 pinned_vm:0x60a ret:0
[52.253726] perf_mmap user->locked_vm:0x408 pinned_vm:0x68b ret:0
[52.253903] perf_mmap user->locked_vm:0x408 pinned_vm:0x70c ret:0
[52.254084] perf_mmap user->locked_vm:0x408 pinned_vm:0x78d ret:0
[52.254263] perf_mmap user->locked_vm:0x408 pinned_vm:0x80e ret:0
The value of user->locked_vm increases to a limit then the memory
is tracked by pinned_vm.
During deallocation the size is subtracted from pinned_vm until
it hits a limit. Then a larger value is subtracted from locked_vm
leading to a large number (because of type unsigned):
[64.267797] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x78d
[64.267826] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x70c
[64.267848] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x68b
[64.267869] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x60a
[64.267891] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x589
[64.267911] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x508
[64.267933] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x487
[64.267952] perf_mmap_close mmap_user->locked_vm:0x408 pinned_vm:0x406
[64.268883] perf_mmap_close mmap_user->locked_vm:0x307 pinned_vm:0x406
[64.269117] perf_mmap_close mmap_user->locked_vm:0x206 pinned_vm:0x406
[64.269433] perf_mmap_close mmap_user->locked_vm:0x105 pinned_vm:0x406
[64.269536] perf_mmap_close mmap_user->locked_vm:0x4 pinned_vm:0x404
[64.269797] perf_mmap_close mmap_user->locked_vm:0xffffffffffffff84 pinned_vm:0x303
[64.270105] perf_mmap_close mmap_user->locked_vm:0xffffffffffffff04 pinned_vm:0x202
[64.270374] perf_mmap_close mmap_user->locked_vm:0xfffffffffffffe84 pinned_vm:0x101
[64.270628] perf_mmap_close mmap_user->locked_vm:0xfffffffffffffe04 pinned_vm:0x0
This value sticks for the user until system is rebooted, causing
follow-on system calls using locked_vm resource limit to fail.
Note: There is no issue using the normal trace buffer.
In fact the issue is in perf_mmap_close(). During allocation auxiliary
trace buffer memory is either traced as 'extra' and added to 'pinned_vm'
or trace as 'user_extra' and added to 'locked_vm'. This applies for
normal trace buffers and auxiliary trace buffer.
However in function perf_mmap_close() all auxiliary trace buffer is
subtraced from 'locked_vm' and never from 'pinned_vm'. This breaks the
ballance.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: gor@linux.ibm.com
Cc: hechaol@fb.com
Cc: heiko.carstens@de.ibm.com
Cc: linux-perf-users@vger.kernel.org
Cc: songliubraving@fb.com
Fixes: d44248a41337 ("perf/core: Rework memory accounting in perf_mmap()")
Link: https://lkml.kernel.org/r/20191021083354.67868-1-tmricht@linux.ibm.com
[ Minor readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d303de1fcf344ff7c15ed64c3f48a991c9958775 ]
A customer reported the following softlockup:
[899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464]
[899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] Kernel panic - not syncing: softlockup: hung tasks
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12
[899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000
[899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00
[899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000
[899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8
[899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000
[899688.160002] tracing_read_pipe+0x336/0x3c0
[899688.160002] __vfs_read+0x26/0x140
[899688.160002] vfs_read+0x87/0x130
[899688.160002] SyS_read+0x42/0x90
[899688.160002] do_syscall_64+0x74/0x160
It caught the process in the middle of trace_access_unlock(). There is
no loop. So, it must be looping in the caller tracing_read_pipe()
via the "waitagain" label.
Crashdump analyze uncovered that iter->seq was completely zeroed
at this point, including iter->seq.seq.size. It means that
print_trace_line() was never able to print anything and
there was no forward progress.
The culprit seems to be in the code:
/* reset all but tr, trace, and overruns */
memset(&iter->seq, 0,
sizeof(struct trace_iterator) -
offsetof(struct trace_iterator, seq));
It was added by the commit 53d0aa773053ab182877 ("ftrace:
add logic to record overruns"). It was v2.6.27-rc1.
It was the time when iter->seq looked like:
struct trace_seq {
unsigned char buffer[PAGE_SIZE];
unsigned int len;
};
There was no "size" variable and zeroing was perfectly fine.
The solution is to reinitialize the structure after or without
zeroing.
Link: http://lkml.kernel.org/r/20191011142134.11997-1-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7fa343b7fdc4f351de4e3f28d5c285937dd1f42f ]
In perf_rotate_context(), when the first cpu flexible event fail to
schedule, cpu_rotate is 1, while cpu_event is NULL. Since cpu_event is
NULL, perf_rotate_context will _NOT_ call cpu_ctx_sched_out(), thus
cpuctx->ctx.is_active will have EVENT_FLEXIBLE set. Then, the next
perf_event_sched_in() will skip all cpu flexible events because of the
EVENT_FLEXIBLE bit.
In the next call of perf_rotate_context(), cpu_rotate stays 1, and
cpu_event stays NULL, so this process repeats. The end result is, flexible
events on this cpu will not be scheduled (until another event being added
to the cpuctx).
Here is an easy repro of this issue. On Intel CPUs, where ref-cycles
could only use one counter, run one pinned event for ref-cycles, one
flexible event for ref-cycles, and one flexible event for cycles. The
flexible ref-cycles is never scheduled, which is expected. However,
because of this issue, the cycles event is never scheduled either.
$ perf stat -e ref-cycles:D,ref-cycles,cycles -C 5 -I 1000
time counts unit events
1.000152973 15,412,480 ref-cycles:D
1.000152973 <not counted> ref-cycles (0.00%)
1.000152973 <not counted> cycles (0.00%)
2.000486957 18,263,120 ref-cycles:D
2.000486957 <not counted> ref-cycles (0.00%)
2.000486957 <not counted> cycles (0.00%)
To fix this, when the flexible_active list is empty, try rotate the
first event in the flexible_groups. Also, rename ctx_first_active() to
ctx_event_to_rotate(), which is more accurate.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <kernel-team@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 8d5bce0c37fa ("perf/core: Optimize perf_rotate_context() event scheduling")
Link: https://lkml.kernel.org/r/20191008165949.920548-1-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d44248a41337731a111374822d7d4451b64e73e4 ]
perf_mmap() always increases user->locked_vm. As a result, "extra" could
grow bigger than "user_extra", which doesn't make sense. Here is an
example case:
(Note: Assume "user_lock_limit" is very small.)
| # of perf_mmap calls |vma->vm_mm->pinned_vm|user->locked_vm|
| 0 | 0 | 0 |
| 1 | user_extra | user_extra |
| 2 | 3 * user_extra | 2 * user_extra|
| 3 | 6 * user_extra | 3 * user_extra|
| 4 | 10 * user_extra | 4 * user_extra|
Fix this by maintaining proper user_extra and extra.
Reviewed-By: Hechao Li <hechaol@fb.com>
Reported-by: Hechao Li <hechaol@fb.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <kernel-team@fb.com>
Cc: Jie Meng <jmeng@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190904214618.3795672-1-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 68e7a4d66b0ce04bf18ff2ffded5596ab3618585 ]
vtime_account_system() assumes that the target task to account cputime
to is always the current task. This is most often true indeed except on
task switch where we call:
vtime_common_task_switch(prev)
vtime_account_system(prev)
Here prev is the scheduling-out task where we account the cputime to. It
doesn't match current that is already the scheduling-in task at this
stage of the context switch.
So we end up checking the wrong task flags to determine if we are
accounting guest or system time to the previous task.
As a result the wrong task is used to check if the target is running in
guest mode. We may then spuriously account or leak either system or
guest time on task switch.
Fix this assumption and also turn vtime_guest_enter/exit() to use the
task passed in parameter as well to avoid future similar issues.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpengli@tencent.com>
Fixes: 2a42eb9594a1 ("sched/cputime: Accumulate vtime on top of nsec clocksource")
Link: https://lkml.kernel.org/r/20190925214242.21873-1-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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ratio precision
[ Upstream commit 4929a4e6faa0f13289a67cae98139e727f0d4a97 ]
The quota/period ratio is used to ensure a child task group won't get
more bandwidth than the parent task group, and is calculated as:
normalized_cfs_quota() = [(quota_us << 20) / period_us]
If the quota/period ratio was changed during this scaling due to
precision loss, it will cause inconsistency between parent and child
task groups.
See below example:
A userspace container manager (kubelet) does three operations:
1) Create a parent cgroup, set quota to 1,000us and period to 10,000us.
2) Create a few children cgroups.
3) Set quota to 1,000us and period to 10,000us on a child cgroup.
These operations are expected to succeed. However, if the scaling of
147/128 happens before step 3, quota and period of the parent cgroup
will be changed:
new_quota: 1148437ns, 1148us
new_period: 11484375ns, 11484us
And when step 3 comes in, the ratio of the child cgroup will be
104857, which will be larger than the parent cgroup ratio (104821),
and will fail.
Scaling them by a factor of 2 will fix the problem.
Tested-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Xuewei Zhang <xueweiz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Phil Auld <pauld@redhat.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Fixes: 2e8e19226398 ("sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup")
Link: https://lkml.kernel.org/r/20191004001243.140897-1-xueweiz@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 6b1340cc00edeadd52ebd8a45171f38c8de2a387 upstream.
A race condition exists while initialiazing perf_trace_buf from
perf_trace_init() and perf_kprobe_init().
CPU0 CPU1
perf_trace_init()
mutex_lock(&event_mutex)
perf_trace_event_init()
perf_trace_event_reg()
total_ref_count == 0
buf = alloc_percpu()
perf_trace_buf[i] = buf
tp_event->class->reg() //fails perf_kprobe_init()
goto fail perf_trace_event_init()
perf_trace_event_reg()
fail:
total_ref_count == 0
total_ref_count == 0
buf = alloc_percpu()
perf_trace_buf[i] = buf
tp_event->class->reg()
total_ref_count++
free_percpu(perf_trace_buf[i])
perf_trace_buf[i] = NULL
Any subsequent call to perf_trace_event_reg() will observe total_ref_count > 0,
causing the perf_trace_buf to be always NULL. This can result in perf_trace_buf
getting accessed from perf_trace_buf_alloc() without being initialized. Acquiring
event_mutex in perf_kprobe_init() before calling perf_trace_event_init() should
fix this race.
The race caused the following bug:
Unable to handle kernel paging request at virtual address 0000003106f2003c
Mem abort info:
ESR = 0x96000045
Exception class = DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000045
CM = 0, WnR = 1
user pgtable: 4k pages, 39-bit VAs, pgdp = ffffffc034b9b000
[0000003106f2003c] pgd=0000000000000000, pud=0000000000000000
Internal error: Oops: 96000045 [#1] PREEMPT SMP
Process syz-executor (pid: 18393, stack limit = 0xffffffc093190000)
pstate: 80400005 (Nzcv daif +PAN -UAO)
pc : __memset+0x20/0x1ac
lr : memset+0x3c/0x50
sp : ffffffc09319fc50
__memset+0x20/0x1ac
perf_trace_buf_alloc+0x140/0x1a0
perf_trace_sys_enter+0x158/0x310
syscall_trace_enter+0x348/0x7c0
el0_svc_common+0x11c/0x368
el0_svc_handler+0x12c/0x198
el0_svc+0x8/0xc
Ramdumps showed the following:
total_ref_count = 3
perf_trace_buf = (
0x0 -> NULL,
0x0 -> NULL,
0x0 -> NULL,
0x0 -> NULL)
Link: http://lkml.kernel.org/r/1571120245-4186-1-git-send-email-prsood@codeaurora.org
Cc: stable@vger.kernel.org
Fixes: e12f03d7031a9 ("perf/core: Implement the 'perf_kprobe' PMU")
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f3a519e4add93b7b31a6616f0b09635ff2e6a159 upstream.
Commit:
8a58ddae2379 ("perf/core: Fix exclusive events' grouping")
allows CAP_EXCLUSIVE events to be grouped with other events. Since all
of those also happen to be AUX events (which is not the case the other
way around, because arch/s390), this changes the rules for stopping the
output: the AUX event may not be on its PMU's context any more, if it's
grouped with a HW event, in which case it will be on that HW event's
context instead. If that's the case, munmap() of the AUX buffer can't
find and stop the AUX event, potentially leaving the last reference with
the atomic context, which will then end up freeing the AUX buffer. This
will then trip warnings:
Fix this by using the context's PMU context when looking for events
to stop, instead of the event's PMU context.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20191022073940.61814-1-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 194c2c74f5532e62c218adeb8e2b683119503907 upstream.
As instances may have different tracers available, we need to look at the
trace_array descriptor that shows the list of the available tracers for the
instance. But there's a race between opening the file and an admin
deleting the instance. The trace_array_get() needs to be called before
accessing the trace_array.
Cc: stable@vger.kernel.org
Fixes: 607e2ea167e56 ("tracing: Set up infrastructure to allow tracers for instances")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9ef16693aff8137faa21d16ffe65bb9832d24d71 upstream.
The ftrace set_ftrace_filter and set_ftrace_notrace files are specific for
an instance now. They need to take a reference to the instance otherwise
there could be a race between accessing the files and deleting the instance.
It wasn't until the :mod: caching where these file operations started
referencing the trace_array directly.
Cc: stable@vger.kernel.org
Fixes: 673feb9d76ab3 ("ftrace: Add :mod: caching infrastructure to trace_array")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit fc64e4ad80d4b72efce116f87b3174f0b7196f8e upstream.
max_latency is intended to record the maximum ever observed hardware
latency, which may occur in either part of the loop (inner/outer). So
we need to also consider the outer-loop sample when updating
max_latency.
Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu
Fixes: e7c15cd8a113 ("tracing: Added hardware latency tracer")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 98dc19c11470ee6048aba723d77079ad2cda8a52 upstream.
nmi_total_ts is supposed to record the total time spent in *all* NMIs
that occur on the given CPU during the (active portion of the)
sampling window. However, the code seems to be overwriting this
variable for each NMI, thereby only recording the time spent in the
most recent NMI. Fix it by accumulating the duration instead.
Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu
Fixes: 7b2c86250122 ("tracing: Add NMI tracing in hwlat detector")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b0f53dbc4bc4c371f38b14c391095a3bb8a0bb40 upstream.
Partially revert 16db3d3f1170 ("kernel/sysctl.c: threads-max observe
limits") because the patch is causing a regression to any workload which
needs to override the auto-tuning of the limit provided by kernel.
set_max_threads is implementing a boot time guesstimate to provide a
sensible limit of the concurrently running threads so that runaways will
not deplete all the memory. This is a good thing in general but there
are workloads which might need to increase this limit for an application
to run (reportedly WebSpher MQ is affected) and that is simply not
possible after the mentioned change. It is also very dubious to
override an admin decision by an estimation that doesn't have any direct
relation to correctness of the kernel operation.
Fix this by dropping set_max_threads from sysctl_max_threads so any
value is accepted as long as it fits into MAX_THREADS which is important
to check because allowing more threads could break internal robust futex
restriction. While at it, do not use MIN_THREADS as the lower boundary
because it is also only a heuristic for automatic estimation and admin
might have a good reason to stop new threads to be created even when
below this limit.
This became more severe when we switched x86 from 4k to 8k kernel
stacks. Starting since 6538b8ea886e ("x86_64: expand kernel stack to
16K") (3.16) we use THREAD_SIZE_ORDER = 2 and that halved the auto-tuned
value.
In the particular case
3.12
kernel.threads-max = 515561
4.4
kernel.threads-max = 200000
Neither of the two values is really insane on 32GB machine.
I am not sure we want/need to tune the max_thread value further. If
anything the tuning should be removed altogether if proven not useful in
general. But we definitely need a way to override this auto-tuning.
Link: http://lkml.kernel.org/r/20190922065801.GB18814@dhcp22.suse.cz
Fixes: 16db3d3f1170 ("kernel/sysctl.c: threads-max observe limits")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 20bb759a66be52cf4a9ddd17fddaf509e11490cd upstream.
Calling 'panic()' on a kernel with CONFIG_PREEMPT=y can leave the
calling CPU in an infinite loop, but with interrupts and preemption
enabled. From this state, userspace can continue to be scheduled,
despite the system being "dead" as far as the kernel is concerned.
This is easily reproducible on arm64 when booting with "nosmp" on the
command line; a couple of shell scripts print out a periodic "Ping"
message whilst another triggers a crash by writing to
/proc/sysrq-trigger:
| sysrq: Trigger a crash
| Kernel panic - not syncing: sysrq triggered crash
| CPU: 0 PID: 1 Comm: init Not tainted 5.2.15 #1
| Hardware name: linux,dummy-virt (DT)
| Call trace:
| dump_backtrace+0x0/0x148
| show_stack+0x14/0x20
| dump_stack+0xa0/0xc4
| panic+0x140/0x32c
| sysrq_handle_reboot+0x0/0x20
| __handle_sysrq+0x124/0x190
| write_sysrq_trigger+0x64/0x88
| proc_reg_write+0x60/0xa8
| __vfs_write+0x18/0x40
| vfs_write+0xa4/0x1b8
| ksys_write+0x64/0xf0
| __arm64_sys_write+0x14/0x20
| el0_svc_common.constprop.0+0xb0/0x168
| el0_svc_handler+0x28/0x78
| el0_svc+0x8/0xc
| Kernel Offset: disabled
| CPU features: 0x0002,24002004
| Memory Limit: none
| ---[ end Kernel panic - not syncing: sysrq triggered crash ]---
| Ping 2!
| Ping 1!
| Ping 1!
| Ping 2!
The issue can also be triggered on x86 kernels if CONFIG_SMP=n,
otherwise local interrupts are disabled in 'smp_send_stop()'.
Disable preemption in 'panic()' before re-enabling interrupts.
Link: http://lkml.kernel.org/r/20191002123538.22609-1-will@kernel.org
Link: https://lore.kernel.org/r/BX1W47JXPMR8.58IYW53H6M5N@dragonstone
Signed-off-by: Will Deacon <will@kernel.org>
Reported-by: Xogium <contact@xogium.me>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit b9023b91dd020ad7e093baa5122b6968c48cc9e0 ]
When a cpu requests broadcasting, before starting the tick broadcast
hrtimer, bc_set_next() checks if the timer callback (bc_handler) is active
using hrtimer_try_to_cancel(). But hrtimer_try_to_cancel() does not provide
the required synchronization when the callback is active on other core.
The callback could have already executed tick_handle_oneshot_broadcast()
and could have also returned. But still there is a small time window where
the hrtimer_try_to_cancel() returns -1. In that case bc_set_next() returns
without doing anything, but the next_event of the tick broadcast clock
device is already set to a timeout value.
In the race condition diagram below, CPU #1 is running the timer callback
and CPU #2 is entering idle state and so calls bc_set_next().
In the worst case, the next_event will contain an expiry time, but the
hrtimer will not be started which happens when the racing callback returns
HRTIMER_NORESTART. The hrtimer might never recover if all further requests
from the CPUs to subscribe to tick broadcast have timeout greater than the
next_event of tick broadcast clock device. This leads to cascading of
failures and finally noticed as rcu stall warnings
Here is a depiction of the race condition
CPU #1 (Running timer callback) CPU #2 (Enter idle
and subscribe to
tick broadcast)
--------------------- ---------------------
__run_hrtimer() tick_broadcast_enter()
bc_handler() __tick_broadcast_oneshot_control()
tick_handle_oneshot_broadcast()
raw_spin_lock(&tick_broadcast_lock);
dev->next_event = KTIME_MAX; //wait for tick_broadcast_lock
//next_event for tick broadcast clock
set to KTIME_MAX since no other cores
subscribed to tick broadcasting
raw_spin_unlock(&tick_broadcast_lock);
if (dev->next_event == KTIME_MAX)
return HRTIMER_NORESTART
// callback function exits without
restarting the hrtimer //tick_broadcast_lock acquired
raw_spin_lock(&tick_broadcast_lock);
tick_broadcast_set_event()
clockevents_program_event()
dev->next_event = expires;
bc_set_next()
hrtimer_try_to_cancel()
//returns -1 since the timer
callback is active. Exits without
restarting the timer
cpu_base->running = NULL;
The comment that hrtimer cannot be armed from within the callback is
wrong. It is fine to start the hrtimer from within the callback. Also it is
safe to start the hrtimer from the enter/exit idle code while the broadcast
handler is active. The enter/exit idle code and the broadcast handler are
synchronized using tick_broadcast_lock. So there is no need for the
existing try to cancel logic. All this can be removed which will eliminate
the race condition as well.
Fixes: 5d1638acb9f6 ("tick: Introduce hrtimer based broadcast")
Originally-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Balasubramani Vivekanandan <balasubramani_vivekanandan@mentor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190926135101.12102-2-balasubramani_vivekanandan@mentor.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 768fb61fcc13b2acaca758275d54c09a65e2968b ]
BPF_PROG_TYPE_SOCK_OPS program can reenter bpf_event_output because it
can be called from atomic and non-atomic contexts since we don't have
bpf_prog_active to prevent it happen.
This patch enables 3 levels of nesting to support normal, irq and nmi
context.
We can easily reproduce the issue by running netperf crr mode with 100
flows and 10 threads from netperf client side.
Here is the whole stack dump:
[ 515.228898] WARNING: CPU: 20 PID: 14686 at kernel/trace/bpf_trace.c:549 bpf_event_output+0x1f9/0x220
[ 515.228903] CPU: 20 PID: 14686 Comm: tcp_crr Tainted: G W 4.15.0-smp-fixpanic #44
[ 515.228904] Hardware name: Intel TBG,ICH10/Ikaria_QC_1b, BIOS 1.22.0 06/04/2018
[ 515.228905] RIP: 0010:bpf_event_output+0x1f9/0x220
[ 515.228906] RSP: 0018:ffff9a57ffc03938 EFLAGS: 00010246
[ 515.228907] RAX: 0000000000000012 RBX: 0000000000000001 RCX: 0000000000000000
[ 515.228907] RDX: 0000000000000000 RSI: 0000000000000096 RDI: ffffffff836b0f80
[ 515.228908] RBP: ffff9a57ffc039c8 R08: 0000000000000004 R09: 0000000000000012
[ 515.228908] R10: ffff9a57ffc1de40 R11: 0000000000000000 R12: 0000000000000002
[ 515.228909] R13: ffff9a57e13bae00 R14: 00000000ffffffff R15: ffff9a57ffc1e2c0
[ 515.228910] FS: 00007f5a3e6ec700(0000) GS:ffff9a57ffc00000(0000) knlGS:0000000000000000
[ 515.228910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 515.228911] CR2: 0000537082664fff CR3: 000000061fed6002 CR4: 00000000000226f0
[ 515.228911] Call Trace:
[ 515.228913] <IRQ>
[ 515.228919] [<ffffffff82c6c6cb>] bpf_sockopt_event_output+0x3b/0x50
[ 515.228923] [<ffffffff8265daee>] ? bpf_ktime_get_ns+0xe/0x10
[ 515.228927] [<ffffffff8266fda5>] ? __cgroup_bpf_run_filter_sock_ops+0x85/0x100
[ 515.228930] [<ffffffff82cf90a5>] ? tcp_init_transfer+0x125/0x150
[ 515.228933] [<ffffffff82cf9159>] ? tcp_finish_connect+0x89/0x110
[ 515.228936] [<ffffffff82cf98e4>] ? tcp_rcv_state_process+0x704/0x1010
[ 515.228939] [<ffffffff82c6e263>] ? sk_filter_trim_cap+0x53/0x2a0
[ 515.228942] [<ffffffff82d90d1f>] ? tcp_v6_inbound_md5_hash+0x6f/0x1d0
[ 515.228945] [<ffffffff82d92160>] ? tcp_v6_do_rcv+0x1c0/0x460
[ 515.228947] [<ffffffff82d93558>] ? tcp_v6_rcv+0x9f8/0xb30
[ 515.228951] [<ffffffff82d737c0>] ? ip6_route_input+0x190/0x220
[ 515.228955] [<ffffffff82d5f7ad>] ? ip6_protocol_deliver_rcu+0x6d/0x450
[ 515.228958] [<ffffffff82d60246>] ? ip6_rcv_finish+0xb6/0x170
[ 515.228961] [<ffffffff82d5fb90>] ? ip6_protocol_deliver_rcu+0x450/0x450
[ 515.228963] [<ffffffff82d60361>] ? ipv6_rcv+0x61/0xe0
[ 515.228966] [<ffffffff82d60190>] ? ipv6_list_rcv+0x330/0x330
[ 515.228969] [<ffffffff82c4976b>] ? __netif_receive_skb_one_core+0x5b/0xa0
[ 515.228972] [<ffffffff82c497d1>] ? __netif_receive_skb+0x21/0x70
[ 515.228975] [<ffffffff82c4a8d2>] ? process_backlog+0xb2/0x150
[ 515.228978] [<ffffffff82c4aadf>] ? net_rx_action+0x16f/0x410
[ 515.228982] [<ffffffff830000dd>] ? __do_softirq+0xdd/0x305
[ 515.228986] [<ffffffff8252cfdc>] ? irq_exit+0x9c/0xb0
[ 515.228989] [<ffffffff82e02de5>] ? smp_call_function_single_interrupt+0x65/0x120
[ 515.228991] [<ffffffff82e020e1>] ? call_function_single_interrupt+0x81/0x90
[ 515.228992] </IRQ>
[ 515.228996] [<ffffffff82a11ff0>] ? io_serial_in+0x20/0x20
[ 515.229000] [<ffffffff8259c040>] ? console_unlock+0x230/0x490
[ 515.229003] [<ffffffff8259cbaa>] ? vprintk_emit+0x26a/0x2a0
[ 515.229006] [<ffffffff8259cbff>] ? vprintk_default+0x1f/0x30
[ 515.229008] [<ffffffff8259d9f5>] ? vprintk_func+0x35/0x70
[ 515.229011] [<ffffffff8259d4bb>] ? printk+0x50/0x66
[ 515.229013] [<ffffffff82637637>] ? bpf_event_output+0xb7/0x220
[ 515.229016] [<ffffffff82c6c6cb>] ? bpf_sockopt_event_output+0x3b/0x50
[ 515.229019] [<ffffffff8265daee>] ? bpf_ktime_get_ns+0xe/0x10
[ 515.229023] [<ffffffff82c29e87>] ? release_sock+0x97/0xb0
[ 515.229026] [<ffffffff82ce9d6a>] ? tcp_recvmsg+0x31a/0xda0
[ 515.229029] [<ffffffff8266fda5>] ? __cgroup_bpf_run_filter_sock_ops+0x85/0x100
[ 515.229032] [<ffffffff82ce77c1>] ? tcp_set_state+0x191/0x1b0
[ 515.229035] [<ffffffff82ced10e>] ? tcp_disconnect+0x2e/0x600
[ 515.229038] [<ffffffff82cecbbb>] ? tcp_close+0x3eb/0x460
[ 515.229040] [<ffffffff82d21082>] ? inet_release+0x42/0x70
[ 515.229043] [<ffffffff82d58809>] ? inet6_release+0x39/0x50
[ 515.229046] [<ffffffff82c1f32d>] ? __sock_release+0x4d/0xd0
[ 515.229049] [<ffffffff82c1f3e5>] ? sock_close+0x15/0x20
[ 515.229052] [<ffffffff8273b517>] ? __fput+0xe7/0x1f0
[ 515.229055] [<ffffffff8273b66e>] ? ____fput+0xe/0x10
[ 515.229058] [<ffffffff82547bf2>] ? task_work_run+0x82/0xb0
[ 515.229061] [<ffffffff824086df>] ? exit_to_usermode_loop+0x7e/0x11f
[ 515.229064] [<ffffffff82408171>] ? do_syscall_64+0x111/0x130
[ 515.229067] [<ffffffff82e0007c>] ? entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Fixes: a5a3a828cd00 ("bpf: add perf event notificaton support for sock_ops")
Signed-off-by: Allan Zhang <allanzhang@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20190925234312.94063-2-allanzhang@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0f74914071ab7e7b78731ed62bf350e3a344e0a5 ]
When building with W=1, gcc properly complains that there's no prototypes:
CC kernel/elfcore.o
kernel/elfcore.c:7:17: warning: no previous prototype for 'elf_core_extra_phdrs' [-Wmissing-prototypes]
7 | Elf_Half __weak elf_core_extra_phdrs(void)
| ^~~~~~~~~~~~~~~~~~~~
kernel/elfcore.c:12:12: warning: no previous prototype for 'elf_core_write_extra_phdrs' [-Wmissing-prototypes]
12 | int __weak elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/elfcore.c:17:12: warning: no previous prototype for 'elf_core_write_extra_data' [-Wmissing-prototypes]
17 | int __weak elf_core_write_extra_data(struct coredump_params *cprm)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
kernel/elfcore.c:22:15: warning: no previous prototype for 'elf_core_extra_data_size' [-Wmissing-prototypes]
22 | size_t __weak elf_core_extra_data_size(void)
| ^~~~~~~~~~~~~~~~~~~~~~~~
Provide the include file so gcc is happy, and we don't have potential code drift
Link: http://lkml.kernel.org/r/29875.1565224705@turing-police
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 714e501e16cd473538b609b3e351b2cc9f7f09ed ]
An oops can be triggered in the scheduler when running qemu on arm64:
Unable to handle kernel paging request at virtual address ffff000008effe40
Internal error: Oops: 96000007 [#1] SMP
Process migration/0 (pid: 12, stack limit = 0x00000000084e3736)
pstate: 20000085 (nzCv daIf -PAN -UAO)
pc : __ll_sc___cmpxchg_case_acq_4+0x4/0x20
lr : move_queued_task.isra.21+0x124/0x298
...
Call trace:
__ll_sc___cmpxchg_case_acq_4+0x4/0x20
__migrate_task+0xc8/0xe0
migration_cpu_stop+0x170/0x180
cpu_stopper_thread+0xec/0x178
smpboot_thread_fn+0x1ac/0x1e8
kthread+0x134/0x138
ret_from_fork+0x10/0x18
__set_cpus_allowed_ptr() will choose an active dest_cpu in affinity mask to
migrage the process if process is not currently running on any one of the
CPUs specified in affinity mask. __set_cpus_allowed_ptr() will choose an
invalid dest_cpu (dest_cpu >= nr_cpu_ids, 1024 in my virtual machine) if
CPUS in an affinity mask are deactived by cpu_down after cpumask_intersects
check. cpumask_test_cpu() of dest_cpu afterwards is overflown and may pass if
corresponding bit is coincidentally set. As a consequence, kernel will
access an invalid rq address associate with the invalid CPU in
migration_cpu_stop->__migrate_task->move_queued_task and the Oops occurs.
The reproduce the crash:
1) A process repeatedly binds itself to cpu0 and cpu1 in turn by calling
sched_setaffinity.
2) A shell script repeatedly does "echo 0 > /sys/devices/system/cpu/cpu1/online"
and "echo 1 > /sys/devices/system/cpu/cpu1/online" in turn.
3) Oops appears if the invalid CPU is set in memory after tested cpumask.
Signed-off-by: KeMeng Shi <shikemeng@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1568616808-16808-1-git-send-email-shikemeng@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit fc0d77387cb5ae883fd774fc559e056a8dde024c ]
Fix a logic flaw in the way membarrier_register_private_expedited()
handles ready state checks for private expedited sync core and private
expedited registrations.
If a private expedited membarrier registration is first performed, and
then a private expedited sync_core registration is performed, the ready
state check will skip the second registration when it really should not.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-2-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 89340d0935c9296c7b8222b6eab30e67cb57ab82 upstream.
This patch reverts commit 75437bb304b20 (locking/pvqspinlock: Don't
wait if vCPU is preempted). A large performance regression was caused
by this commit. on over-subscription scenarios.
The test was run on a Xeon Skylake box, 2 sockets, 40 cores, 80 threads,
with three VMs of 80 vCPUs each. The score of ebizzy -M is reduced from
13000-14000 records/s to 1700-1800 records/s:
Host Guest score
vanilla w/o kvm optimizations upstream 1700-1800 records/s
vanilla w/o kvm optimizations revert 13000-14000 records/s
vanilla w/ kvm optimizations upstream 4500-5000 records/s
vanilla w/ kvm optimizations revert 14000-15500 records/s
Exit from aggressive wait-early mechanism can result in premature yield
and extra scheduling latency.
Actually, only 6% of wait_early events are caused by vcpu_is_preempted()
being true. However, when one vCPU voluntarily releases its vCPU, all
the subsequently waiters in the queue will do the same and the cascading
effect leads to bad performance.
kvm optimizations:
[1] commit d73eb57b80b (KVM: Boost vCPUs that are delivering interrupts)
[2] commit 266e85a5ec9 (KVM: X86: Boost queue head vCPU to mitigate lock waiter preemption)
Tested-by: loobinliu@tencent.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: loobinliu@tencent.com
Cc: stable@vger.kernel.org
Fixes: 75437bb304b20 (locking/pvqspinlock: Don't wait if vCPU is preempted)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e430d802d6a3aaf61bd3ed03d9404888a29b9bf9 upstream.
The timer delayed for more than 3 seconds warning was triggered during
testing.
Workqueue: events_unbound sched_tick_remote
RIP: 0010:sched_tick_remote+0xee/0x100
...
Call Trace:
process_one_work+0x18c/0x3a0
worker_thread+0x30/0x380
kthread+0x113/0x130
ret_from_fork+0x22/0x40
The reason is that the code in collect_expired_timers() uses jiffies
unprotected:
if (next_event > jiffies)
base->clk = jiffies;
As the compiler is allowed to reload the value base->clk can advance
between the check and the store and in the worst case advance farther than
next event. That causes the timer expiry to be delayed until the wheel
pointer wraps around.
Convert the code to use READ_ONCE()
Fixes: 236968383cf5 ("timers: Optimize collect_expired_timers() for NOHZ")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Liang ZhiCheng <liangzhicheng@baidu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1568894687-14499-1-git-send-email-lirongqing@baidu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 17f8607a1658a8e70415eef67909f990d13017b5 upstream.
Original changelog from Steve Rostedt (except last sentence which
explains the problem, and the Fixes: tag):
I performed a three way histogram with the following commands:
echo 'irq_lat u64 lat pid_t pid' > synthetic_events
echo 'wake_lat u64 lat u64 irqlat pid_t pid' >> synthetic_events
echo 'hist:keys=common_pid:irqts=common_timestamp.usecs if function == 0xffffffff81200580' > events/timer/hrtimer_start/trigger
echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$irqts:onmatch(timer.hrtimer_start).irq_lat($lat,pid) if common_flags & 1' > events/sched/sched_waking/trigger
echo 'hist:keys=pid:wakets=common_timestamp.usecs,irqlat=lat' > events/synthetic/irq_lat/trigger
echo 'hist:keys=next_pid:lat=common_timestamp.usecs-$wakets,irqlat=$irqlat:onmatch(synthetic.irq_lat).wake_lat($lat,$irqlat,next_pid)' > events/sched/sched_switch/trigger
echo 1 > events/synthetic/wake_lat/enable
Basically I wanted to see:
hrtimer_start (calling function tick_sched_timer)
Note:
# grep tick_sched_timer /proc/kallsyms
ffffffff81200580 t tick_sched_timer
And save the time of that, and then record sched_waking if it is called
in interrupt context and with the same pid as the hrtimer_start, it
will record the latency between that and the waking event.
I then look at when the task that is woken is scheduled in, and record
the latency between the wakeup and the task running.
At the end, the wake_lat synthetic event will show the wakeup to
scheduled latency, as well as the irq latency in from hritmer_start to
the wakeup. The problem is that I found this:
<idle>-0 [007] d... 190.485261: wake_lat: lat=27 irqlat=190485230 pid=698
<idle>-0 [005] d... 190.485283: wake_lat: lat=40 irqlat=190485239 pid=10
<idle>-0 [002] d... 190.488327: wake_lat: lat=56 irqlat=190488266 pid=335
<idle>-0 [005] d... 190.489330: wake_lat: lat=64 irqlat=190489262 pid=10
<idle>-0 [003] d... 190.490312: wake_lat: lat=43 irqlat=190490265 pid=77
<idle>-0 [005] d... 190.493322: wake_lat: lat=54 irqlat=190493262 pid=10
<idle>-0 [005] d... 190.497305: wake_lat: lat=35 irqlat=190497267 pid=10
<idle>-0 [005] d... 190.501319: wake_lat: lat=50 irqlat=190501264 pid=10
The irqlat seemed quite large! Investigating this further, if I had
enabled the irq_lat synthetic event, I noticed this:
<idle>-0 [002] d.s. 249.429308: irq_lat: lat=164968 pid=335
<idle>-0 [002] d... 249.429369: wake_lat: lat=55 irqlat=249429308 pid=335
Notice that the timestamp of the irq_lat "249.429308" is awfully
similar to the reported irqlat variable. In fact, all instances were
like this. It appeared that:
irqlat=$irqlat
Wasn't assigning the old $irqlat to the new irqlat variable, but
instead was assigning the $irqts to it.
The issue is that assigning the old $irqlat to the new irqlat variable
creates a variable reference alias, but the alias creation code
forgets to make sure the alias uses the same var_ref_idx to access the
reference.
Link: http://lkml.kernel.org/r/1567375321.5282.12.camel@kernel.org
Cc: Linux Trace Devel <linux-trace-devel@vger.kernel.org>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 7e8b88a30b085 ("tracing: Add hist trigger support for variable reference aliases")
Reported-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7c3a6aedcd6aae0a32a527e68669f7dd667492d1 upstream.
syzbot found that a thread can stall for minutes inside kexec_load() after
that thread was killed by SIGKILL [1]. It turned out that the reproducer
was trying to allocate 2408MB of memory using kimage_alloc_page() from
kimage_load_normal_segment(). Let's check for SIGKILL before doing memory
allocation.
[1] https://syzkaller.appspot.com/bug?id=a0e3436829698d5824231251fad9d8e998f94f5e
Link: http://lkml.kernel.org/r/993c9185-d324-2640-d061-bed2dd18b1f7@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+8ab2d0f39fb79fe6ca40@syzkaller.appspotmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 4ff96fb52c6964ad42e0a878be8f86a2e8052ddd ]
klp_module_coming() is called for every module appearing in the system.
It sets obj->mod to a patched module for klp_object obj. Unfortunately
it leaves it set even if an error happens later in the function and the
patched module is not allowed to be loaded.
klp_is_object_loaded() uses obj->mod variable and could currently give a
wrong return value. The bug is probably harmless as of now.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit f18ddc13af981ce3c7b7f26925f099e7c6929aba upstream.
ENOTSUPP is not supposed to be returned to userspace. This was found on an
OpenPower machine, where the RTC does not support set_alarm.
On that system, a clock_nanosleep(CLOCK_REALTIME_ALARM, ...) results in
"524 Unknown error 524"
Replace it with EOPNOTSUPP which results in the expected "95 Operation not
supported" error.
Fixes: 1c6b39ad3f01 (alarmtimers: Return -ENOTSUPP if no RTC device is present)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190903171802.28314-1-cascardo@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 130d9c331bc59a8733b47c58ef197a2b1fa3ed43 ]
A rather embarrasing mistake had us call sched_setscheduler() before
initializing the parameters passed to it.
Fixes: 1a763fd7c633 ("rcu/tree: Call setschedule() gp ktread to SCHED_FIFO outside of atomic region")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit c9dccacfccc72c32692eedff4a27a4b0833a2afd upstream.
kmsg_dump_get_buffer() is supposed to select all the youngest log
messages which fit into the provided buffer. It determines the correct
start index by using msg_print_text() with a NULL buffer to calculate
the size of each entry. However, when performing the actual writes,
msg_print_text() only writes the entry to the buffer if the written len
is lesser than the size of the buffer. So if the lengths of the
selected youngest log messages happen to precisely fill up the provided
buffer, the last log message is not included.
We don't want to modify msg_print_text() to fill up the buffer and start
returning a length which is equal to the size of the buffer, since
callers of its other users, such as kmsg_dump_get_line(), depend upon
the current behaviour.
Instead, fix kmsg_dump_get_buffer() to compensate for this.
For example, with the following two final prints:
[ 6.427502] AAAAAAAAAAAAA
[ 6.427769] BBBBBBBB12345
A dump of a 64-byte buffer filled by kmsg_dump_get_buffer(), before this
patch:
00000000: 3c 30 3e 5b 20 20 20 20 36 2e 35 32 32 31 39 37 <0>[ 6.522197
00000010: 5d 20 41 41 41 41 41 41 41 41 41 41 41 41 41 0a ] AAAAAAAAAAAAA.
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
After this patch:
00000000: 3c 30 3e 5b 20 20 20 20 36 2e 34 35 36 36 37 38 <0>[ 6.456678
00000010: 5d 20 42 42 42 42 42 42 42 42 31 32 33 34 35 0a ] BBBBBBBB12345.
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
Link: http://lkml.kernel.org/r/20190711142937.4083-1-vincent.whitchurch@axis.com
Fixes: e2ae715d66bf4bec ("kmsg - kmsg_dump() use iterator to receive log buffer content")
To: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.5+
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 4adcdcea717cb2d8436bef00dd689aa5bc76f11b ]
When passing a equal or more then 32 bytes long string to psi_write(),
psi_write() copies 31 bytes to its buf and overwrites buf[30]
with '\0'. Which makes the input string 1 byte shorter than
it should be.
Fix it by copying sizeof(buf) bytes when nbytes >= sizeof(buf).
This does not cause problems in normal use case like:
"some 500000 10000000" or "full 500000 10000000" because they
are less than 32 bytes in length.
/* assuming nbytes == 35 */
char buf[32];
buf_size = min(nbytes, (sizeof(buf) - 1)); /* buf_size = 31 */
if (copy_from_user(buf, user_buf, buf_size))
return -EFAULT;
buf[buf_size - 1] = '\0'; /* buf[30] = '\0' */
Before:
%cd /proc/pressure/
%echo "123456789|123456789|123456789|1234" > memory
[ 22.473497] nbytes=35,buf_size=31
[ 22.473775] 123456789|123456789|123456789| (print 30 chars)
%sh: write error: Invalid argument
%echo "123456789|123456789|123456789|1" > memory
[ 64.916162] nbytes=32,buf_size=31
[ 64.916331] 123456789|123456789|123456789| (print 30 chars)
%sh: write error: Invalid argument
After:
%cd /proc/pressure/
%echo "123456789|123456789|123456789|1234" > memory
[ 254.837863] nbytes=35,buf_size=32
[ 254.838541] 123456789|123456789|123456789|1 (print 31 chars)
%sh: write error: Invalid argument
%echo "123456789|123456789|123456789|1" > memory
[ 9965.714935] nbytes=32,buf_size=32
[ 9965.715096] 123456789|123456789|123456789|1 (print 31 chars)
%sh: write error: Invalid argument
Also remove the superfluous parentheses.
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Cc: <linux-mediatek@lists.infradead.org>
Cc: <wsd_upstream@mediatek.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190912103452.13281-1-miles.chen@mediatek.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e336b4027775cb458dc713745e526fa1a1996b2a ]
Since BUG() and WARN() may use a trap (e.g. UD2 on x86) to
get the address where the BUG() has occurred, kprobes can not
do single-step out-of-line that instruction. So prohibit
probing on such address.
Without this fix, if someone put a kprobe on WARN(), the
kernel will crash with invalid opcode error instead of
outputing warning message, because kernel can not find
correct bug address.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/156750890133.19112.3393666300746167111.stgit@devnote2
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 8f35eaa5f2de020073a48ad51112237c5932cfcc ]
On architectures that discard .exit.* sections at runtime, a
warning is printed for each jump label that is used within an
in-kernel __exit annotated function:
can't patch jump_label at ehci_hcd_cleanup+0x8/0x3c
WARNING: CPU: 0 PID: 1 at kernel/jump_label.c:410 __jump_label_update+0x12c/0x138
As these functions will never get executed (they are free'd along
with the rest of initmem) - we do not need to patch them and should
not display any warnings.
The warning is displayed because the test required to satisfy
jump_entry_is_init is based on init_section_contains (__init_begin to
__init_end) whereas the test in __jump_label_update is based on
init_kernel_text (_sinittext to _einittext) via kernel_text_address).
Fixes: 19483677684b ("jump_label: Annotate entries that operate on __init code earlier")
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 77c84dd1881d0f0176cb678d770bfbda26c54390 ]
Fast switching path only emits an event for the CPU of interest, whereas the
regular path emits an event for all the CPUs that had their frequency changed,
i.e. all the CPUs sharing the same policy.
With the current behavior, looking at cpu_frequency event for a given CPU that
is using the fast switching path will not give the correct frequency signal.
Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 692117c1f7a6770ed41dd8f277cd9fed1dfb16f1 ]
Warning when p == NULL and then proceeding and dereferencing p does not
make any sense as the kernel will crash with a NULL pointer dereference
right away.
Bailing out when p == NULL and returning an error code does not cure the
underlying problem which caused p to be NULL. Though it might allow to
do proper debugging.
Same applies to the clock id check in set_process_cpu_timer().
Clean them up and make them return without trying to do further damage.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190819143801.846497772@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e78a7614f3876ac649b3df608789cb6ef74d0480 ]
Scheduling-clock interrupts can arrive late in the CPU-offline process,
after idle entry and the subsequent call to cpuhp_report_idle_dead().
Once execution passes the call to rcu_report_dead(), RCU is ignoring
the CPU, which results in lockdep complaints when the interrupt handler
uses RCU:
------------------------------------------------------------------------
=============================
WARNING: suspicious RCU usage
5.2.0-rc1+ #681 Not tainted
-----------------------------
kernel/sched/fair.c:9542 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from offline CPU!
rcu_scheduler_active = 2, debug_locks = 1
no locks held by swapper/5/0.
stack backtrace:
CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.2.0-rc1+ #681
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Bochs 01/01/2011
Call Trace:
<IRQ>
dump_stack+0x5e/0x8b
trigger_load_balance+0xa8/0x390
? tick_sched_do_timer+0x60/0x60
update_process_times+0x3b/0x50
tick_sched_handle+0x2f/0x40
tick_sched_timer+0x32/0x70
__hrtimer_run_queues+0xd3/0x3b0
hrtimer_interrupt+0x11d/0x270
? sched_clock_local+0xc/0x74
smp_apic_timer_interrupt+0x79/0x200
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:delay_tsc+0x22/0x50
Code: ff 0f 1f 80 00 00 00 00 65 44 8b 05 18 a7 11 48 0f ae e8 0f 31 48 89 d6 48 c1 e6 20 48 09 c6 eb 0e f3 90 65 8b 05 fe a6 11 48 <41> 39 c0 75 18 0f ae e8 0f 31 48 c1 e2 20 48 09 c2 48 89 d0 48 29
RSP: 0000:ffff8f92c0157ed0 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000005 RBX: ffff8c861f356400 RCX: ffff8f92c0157e64
RDX: 000000321214c8cc RSI: 00000032120daa7f RDI: 0000000000260f15
RBP: 0000000000000005 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8c861ee18000 R15: ffff8c861ee18000
cpuhp_report_idle_dead+0x31/0x60
do_idle+0x1d5/0x200
? _raw_spin_unlock_irqrestore+0x2d/0x40
cpu_startup_entry+0x14/0x20
start_secondary+0x151/0x170
secondary_startup_64+0xa4/0xb0
------------------------------------------------------------------------
This happens rarely, but can be forced by happen more often by
placing delays in cpuhp_report_idle_dead() following the call to
rcu_report_dead(). With this in place, the following rcutorture
scenario reproduces the problem within a few minutes:
tools/testing/selftests/rcutorture/bin/kvm.sh --cpus 8 --duration 5 --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" --configs "TREE04"
This commit uses the crude but effective expedient of moving the disabling
of interrupts within the idle loop to precede the cpu_is_offline()
check. It also invokes tick_nohz_idle_stop_tick() instead of
tick_nohz_idle_stop_tick_protected() to shut off the scheduling-clock
interrupt.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
[ paulmck: Revert tick_nohz_idle_stop_tick_protected() removal, new callers. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a46d14eca7b75fffe35603aa8b81df654353d80f ]
Enabling WARN_DOUBLE_CLOCK in /sys/kernel/debug/sched_features causes
warning to fire in update_rq_clock. This seems to be caused by onlining
a new fair sched group not using the rq lock wrappers.
[] rq->clock_update_flags & RQCF_UPDATED
[] WARNING: CPU: 5 PID: 54385 at kernel/sched/core.c:210 update_rq_clock+0xec/0x150
[] Call Trace:
[] online_fair_sched_group+0x53/0x100
[] cpu_cgroup_css_online+0x16/0x20
[] online_css+0x1c/0x60
[] cgroup_apply_control_enable+0x231/0x3b0
[] cgroup_mkdir+0x41b/0x530
[] kernfs_iop_mkdir+0x61/0xa0
[] vfs_mkdir+0x108/0x1a0
[] do_mkdirat+0x77/0xe0
[] do_syscall_64+0x55/0x1d0
[] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Using the wrappers in online_fair_sched_group instead of the raw locking
removes this warning.
[ tglx: Use rq_*lock_irq() ]
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20190801133749.11033-1-pauld@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit fbad01af8c3bb9618848abde8054ab7e0c2330fe ]
The synchronize_rcu_expedited() function has an INIT_WORK_ONSTACK(),
but lacks the corresponding destroy_work_on_stack(). This commit
therefore adds destroy_work_on_stack().
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 1a763fd7c6335e3122c1cc09576ef6c99ada4267 ]
sched_setscheduler() needs to acquire cpuset_rwsem, but it is currently
called from an invalid (atomic) context by rcu_spawn_gp_kthread().
Fix that by simply moving sched_setscheduler_nocheck() call outside of
the atomic region, as it doesn't actually require to be guarded by
rcu_node lock.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: mathieu.poirier@linaro.org
Cc: rostedt@goodmis.org
Cc: tj@kernel.org
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-8-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 59d06cea1198d665ba11f7e8c5f45b00ff2e4812 ]
If a task happens to be throttled while the CPU it was running on gets
hotplugged off, the bandwidth associated with the task is not correctly
migrated with it when the replenishment timer fires (offline_migration).
Fix things up, for this_bw, running_bw and total_bw, when replenishment
timer fires and task is migrated (dl_task_offline_migration()).
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: mathieu.poirier@linaro.org
Cc: rostedt@goodmis.org
Cc: tj@kernel.org
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-5-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a07db5c0865799ebed1f88be0df50c581fb65029 ]
On !CONFIG_RT_GROUP_SCHED configurations it is currently not possible to
move RT tasks between cgroups to which CPU controller has been attached;
but it is oddly possible to first move tasks around and then make them
RT (setschedule to FIFO/RR).
E.g.:
# mkdir /sys/fs/cgroup/cpu,cpuacct/group1
# chrt -fp 10 $$
# echo $$ > /sys/fs/cgroup/cpu,cpuacct/group1/tasks
bash: echo: write error: Invalid argument
# chrt -op 0 $$
# echo $$ > /sys/fs/cgroup/cpu,cpuacct/group1/tasks
# chrt -fp 10 $$
# cat /sys/fs/cgroup/cpu,cpuacct/group1/tasks
2345
2598
# chrt -p 2345
pid 2345's current scheduling policy: SCHED_FIFO
pid 2345's current scheduling priority: 10
Also, as Michal noted, it is currently not possible to enable CPU
controller on unified hierarchy with !CONFIG_RT_GROUP_SCHED (if there
are any kernel RT threads in root cgroup, they can't be migrated to the
newly created CPU controller's root in cgroup_update_dfl_csses()).
Existing code comes with a comment saying the "we don't support RT-tasks
being in separate groups". Such comment is however stale and belongs to
pre-RT_GROUP_SCHED times. Also, it doesn't make much sense for
!RT_GROUP_ SCHED configurations, since checks related to RT bandwidth
are not performed at all in these cases.
Make moving RT tasks between CPU controller groups viable by removing
special case check for RT (and DEADLINE) tasks.
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: rostedt@goodmis.org
Link: https://lkml.kernel.org/r/20190719063455.27328-1-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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