From 68d8681e97bd1c90259f341c1695af05002070ef Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Fri, 2 Aug 2019 21:48:33 -0700 Subject: kernel/signal.c: fix a kernel-doc markup The kernel-doc parser doesn't handle expressions with %foo*. Instead, when an asterisk should be part of a constant, it uses an alternative notation: `foo*`. Link: http://lkml.kernel.org/r/7f18c2e0b5e39e6b7eb55ddeb043b8b260b49f2d.1563361575.git.mchehab+samsung@kernel.org Signed-off-by: Mauro Carvalho Chehab Cc: Deepa Dinamani Cc: Jonathan Corbet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/signal.c b/kernel/signal.c index 349f5a67f100..e667be6907d7 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -349,7 +349,7 @@ void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask) * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop. * Group stop states are cleared and the group stop count is consumed if * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group - * stop, the appropriate %SIGNAL_* flags are set. + * stop, the appropriate `SIGNAL_*` flags are set. * * CONTEXT: * Must be called with @task->sighand->siglock held. -- cgit v1.2.3 From df9576def004d2cd5beedc00cb6e8901427634b9 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Fri, 2 Aug 2019 21:48:37 -0700 Subject: Revert "kmemleak: allow to coexist with fault injection" When running ltp's oom test with kmemleak enabled, the below warning was triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is passed in: WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50 Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014 RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50 ... kmemleak_alloc+0x4e/0xb0 kmem_cache_alloc+0x2a7/0x3e0 mempool_alloc_slab+0x2d/0x40 mempool_alloc+0x118/0x2b0 bio_alloc_bioset+0x19d/0x350 get_swap_bio+0x80/0x230 __swap_writepage+0x5ff/0xb20 The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak has __GFP_NOFAIL set all the time due to d9570ee3bd1d4f2 ("kmemleak: allow to coexist with fault injection"). But, it doesn't make any sense to have __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same time. According to the discussion on the mailing list, the commit should be reverted for short term solution. Catalin Marinas would follow up with a better solution for longer term. The failure rate of kmemleak metadata allocation may increase in some circumstances, but this should be expected side effect. Link: http://lkml.kernel.org/r/1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com Fixes: d9570ee3bd1d4f2 ("kmemleak: allow to coexist with fault injection") Signed-off-by: Yang Shi Suggested-by: Catalin Marinas Acked-by: Michal Hocko Cc: Dmitry Vyukov Cc: David Rientjes Cc: Matthew Wilcox Cc: Qian Cai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/kmemleak.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index dbbd518fb6b3..6e9e8cca663e 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -114,7 +114,7 @@ /* GFP bitmask for kmemleak internal allocations */ #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ __GFP_NORETRY | __GFP_NOMEMALLOC | \ - __GFP_NOWARN | __GFP_NOFAIL) + __GFP_NOWARN) /* scanning area inside a memory block */ struct kmemleak_scan_area { -- cgit v1.2.3 From 7bc36e3ce91471b6377c8eadc0a2f220a2280083 Mon Sep 17 00:00:00 2001 From: YueHaibing Date: Fri, 2 Aug 2019 21:48:40 -0700 Subject: ocfs2: remove set but not used variable 'last_hash' Fixes gcc '-Wunused-but-set-variable' warning: fs/ocfs2/xattr.c: In function ocfs2_xattr_bucket_find: fs/ocfs2/xattr.c:3828:6: warning: variable last_hash set but not used [-Wunused-but-set-variable] It's never used and can be removed. Link: http://lkml.kernel.org/r/20190716132110.34836-1-yuehaibing@huawei.com Signed-off-by: YueHaibing Acked-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Gang He Cc: Jun Piao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/xattr.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 385f3aaa2448..90c830e3758e 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -3825,7 +3825,6 @@ static int ocfs2_xattr_bucket_find(struct inode *inode, u16 blk_per_bucket = ocfs2_blocks_per_xattr_bucket(inode->i_sb); int low_bucket = 0, bucket, high_bucket; struct ocfs2_xattr_bucket *search; - u32 last_hash; u64 blkno, lower_blkno = 0; search = ocfs2_xattr_bucket_new(inode); @@ -3869,8 +3868,6 @@ static int ocfs2_xattr_bucket_find(struct inode *inode, if (xh->xh_count) xe = &xh->xh_entries[le16_to_cpu(xh->xh_count) - 1]; - last_hash = le32_to_cpu(xe->xe_name_hash); - /* record lower_blkno which may be the insert place. */ lower_blkno = blkno; -- cgit v1.2.3 From fa1e512fac717f34e7c12d7a384c46e90a647392 Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Fri, 2 Aug 2019 21:48:44 -0700 Subject: mm: vmscan: check if mem cgroup is disabled or not before calling memcg slab shrinker Shakeel Butt reported premature oom on kernel with "cgroup_disable=memory" since mem_cgroup_is_root() returns false even though memcg is actually NULL. The drop_caches is also broken. It is because commit aeed1d325d42 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()") removed the !memcg check before !mem_cgroup_is_root(). And, surprisingly root memcg is allocated even though memory cgroup is disabled by kernel boot parameter. Add mem_cgroup_disabled() check to make reclaimer work as expected. Link: http://lkml.kernel.org/r/1563385526-20805-1-git-send-email-yang.shi@linux.alibaba.com Fixes: aeed1d325d42 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()") Signed-off-by: Yang Shi Reported-by: Shakeel Butt Reviewed-by: Shakeel Butt Reviewed-by: Kirill Tkhai Acked-by: Michal Hocko Cc: Jan Hadrava Cc: Vladimir Davydov Cc: Johannes Weiner Cc: Roman Gushchin Cc: Hugh Dickins Cc: Qian Cai Cc: Kirill A. Shutemov Cc: [4.19+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 44df66a98f2a..dbdc46a84f63 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -699,7 +699,14 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, unsigned long ret, freed = 0; struct shrinker *shrinker; - if (!mem_cgroup_is_root(memcg)) + /* + * The root memcg might be allocated even though memcg is disabled + * via "cgroup_disable=memory" boot parameter. This could make + * mem_cgroup_is_root() return false, then just run memcg slab + * shrink, but skip global shrink. This may result in premature + * oom. + */ + if (!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg)) return shrink_slab_memcg(gfp_mask, nid, memcg, priority); if (!down_read_trylock(&shrinker_rwsem)) -- cgit v1.2.3 From ebdf4de5642fb6580b0763158b6b4b791c4d6a4d Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 2 Aug 2019 21:48:47 -0700 Subject: mm: migrate: fix reference check race between __find_get_block() and migration buffer_migrate_page_norefs() can race with bh users in the following way: CPU1 CPU2 buffer_migrate_page_norefs() buffer_migrate_lock_buffers() checks bh refs spin_unlock(&mapping->private_lock) __find_get_block() spin_lock(&mapping->private_lock) grab bh ref spin_unlock(&mapping->private_lock) move page do bh work This can result in various issues like lost updates to buffers (i.e. metadata corruption) or use after free issues for the old page. This patch closes the race by holding mapping->private_lock while the mapping is being moved to a new page. Ordinarily, a reference can be taken outside of the private_lock using the per-cpu BH LRU but the references are checked and the LRU invalidated if necessary. The private_lock is held once the references are known so the buffer lookup slow path will spin on the private_lock. Between the page lock and private_lock, it should be impossible for other references to be acquired and updates to happen during the migration. A user had reported data corruption issues on a distribution kernel with a similar page migration implementation as mainline. The data corruption could not be reproduced with this patch applied. A small number of migration-intensive tests were run and no performance problems were noted. [mgorman@techsingularity.net: Changelog, removed tracing] Link: http://lkml.kernel.org/r/20190718090238.GF24383@techsingularity.net Fixes: 89cb0888ca14 "mm: migrate: provide buffer_migrate_page_norefs()" Signed-off-by: Jan Kara Signed-off-by: Mel Gorman Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index 8992741f10aa..515718392b24 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -767,12 +767,12 @@ recheck_buffers: } bh = bh->b_this_page; } while (bh != head); - spin_unlock(&mapping->private_lock); if (busy) { if (invalidated) { rc = -EAGAIN; goto unlock_buffers; } + spin_unlock(&mapping->private_lock); invalidate_bh_lrus(); invalidated = true; goto recheck_buffers; @@ -805,6 +805,8 @@ recheck_buffers: rc = MIGRATEPAGE_SUCCESS; unlock_buffers: + if (check_refs) + spin_unlock(&mapping->private_lock); bh = head; do { unlock_buffer(bh); -- cgit v1.2.3 From 670105a25608affe01cb0ccdc2a1f4bd2327172b Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Fri, 2 Aug 2019 21:48:51 -0700 Subject: mm: compaction: avoid 100% CPU usage during compaction when a task is killed "howaboutsynergy" reported via kernel buzilla number 204165 that compact_zone_order was consuming 100% CPU during a stress test for prolonged periods of time. Specifically the following command, which should exit in 10 seconds, was taking an excessive time to finish while the CPU was pegged at 100%. stress -m 220 --vm-bytes 1000000000 --timeout 10 Tracing indicated a pattern as follows stress-3923 [007] 519.106208: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106212: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106216: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106219: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106223: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106227: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106231: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106235: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106238: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 stress-3923 [007] 519.106242: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0 Note that compaction is entered in rapid succession while scanning and isolating nothing. The problem is that when a task that is compacting receives a fatal signal, it retries indefinitely instead of exiting while making no progress as a fatal signal is pending. It's not easy to trigger this condition although enabling zswap helps on the basis that the timing is altered. A very small window has to be hit for the problem to occur (signal delivered while compacting and isolating a PFN for migration that is not aligned to SWAP_CLUSTER_MAX). This was reproduced locally -- 16G single socket system, 8G swap, 30% zswap configured, vm-bytes 22000000000 using Colin Kings stress-ng implementation from github running in a loop until the problem hits). Tracing recorded the problem occurring almost 200K times in a short window. With this patch, the problem hit 4 times but the task existed normally instead of consuming CPU. This problem has existed for some time but it was made worse by commit cf66f0700c8f ("mm, compaction: do not consider a need to reschedule as contention"). Before that commit, if the same condition was hit then locks would be quickly contended and compaction would exit that way. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204165 Link: http://lkml.kernel.org/r/20190718085708.GE24383@techsingularity.net Fixes: cf66f0700c8f ("mm, compaction: do not consider a need to reschedule as contention") Signed-off-by: Mel Gorman Reviewed-by: Vlastimil Babka Cc: [5.1+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/compaction.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 9e1b9acb116b..952dc2fb24e5 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -842,13 +842,15 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, /* * Periodically drop the lock (if held) regardless of its - * contention, to give chance to IRQs. Abort async compaction - * if contended. + * contention, to give chance to IRQs. Abort completely if + * a fatal signal is pending. */ if (!(low_pfn % SWAP_CLUSTER_MAX) && compact_unlock_should_abort(&pgdat->lru_lock, - flags, &locked, cc)) - break; + flags, &locked, cc)) { + low_pfn = 0; + goto fatal_pending; + } if (!pfn_valid_within(low_pfn)) goto isolate_fail; @@ -1060,6 +1062,7 @@ isolate_abort: trace_mm_compaction_isolate_migratepages(start_pfn, low_pfn, nr_scanned, nr_isolated); +fatal_pending: cc->total_migrate_scanned += nr_scanned; if (nr_isolated) count_compact_events(COMPACTISOLATED, nr_isolated); -- cgit v1.2.3 From ebb6d35a74ce21ce1673b8f404c1039d5a1e7e2d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 2 Aug 2019 21:48:54 -0700 Subject: kasan: remove clang version check for KASAN_STACK asan-stack mode still uses dangerously large kernel stacks of tens of kilobytes in some drivers, and it does not seem that anyone is working on the clang bug. Turn it off for all clang versions to prevent users from accidentally enabling it once they update to clang-9, and to help automated build testing with clang-9. Link: https://bugs.llvm.org/show_bug.cgi?id=38809 Link: http://lkml.kernel.org/r/20190719200347.2596375-1-arnd@arndb.de Fixes: 6baec880d7a5 ("kasan: turn off asan-stack for clang-8 and earlier") Signed-off-by: Arnd Bergmann Acked-by: Nick Desaulniers Reviewed-by: Mark Brown Reviewed-by: Andrey Ryabinin Cc: Qian Cai Cc: Andrey Konovalov Cc: Vasily Gorbik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.kasan | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index 4fafba1a923b..7fa97a8b5717 100644 --- a/lib/Kconfig.kasan +++ b/lib/Kconfig.kasan @@ -106,7 +106,6 @@ endchoice config KASAN_STACK_ENABLE bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST - default !(CLANG_VERSION < 90000) depends on KASAN help The LLVM stack address sanitizer has a know problem that @@ -115,11 +114,11 @@ config KASAN_STACK_ENABLE Disabling asan-stack makes it safe to run kernels build with clang-8 with KASAN enabled, though it loses some of the functionality. - This feature is always disabled when compile-testing with clang-8 - or earlier to avoid cluttering the output in stack overflow - warnings, but clang-8 users can still enable it for builds without - CONFIG_COMPILE_TEST. On gcc and later clang versions it is - assumed to always be safe to use and enabled by default. + This feature is always disabled when compile-testing with clang + to avoid cluttering the output in stack overflow warnings, + but clang users can still enable it for builds without + CONFIG_COMPILE_TEST. On gcc it is assumed to always be safe + to use and enabled by default. config KASAN_STACK int -- cgit v1.2.3 From af700eaed0564d5d3963a7a51cb0843629d7fe3d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 2 Aug 2019 21:48:58 -0700 Subject: ubsan: build ubsan.c more conservatively objtool points out several conditions that it does not like, depending on the combination with other configuration options and compiler variants: stack protector: lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0xbf: call to __stack_chk_fail() with UACCESS enabled lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0xbe: call to __stack_chk_fail() with UACCESS enabled stackleak plugin: lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x4a: call to stackleak_track_stack() with UACCESS enabled lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x4a: call to stackleak_track_stack() with UACCESS enabled kasan: lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x25: call to memcpy() with UACCESS enabled lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x25: call to memcpy() with UACCESS enabled The stackleak and kasan options just need to be disabled for this file as we do for other files already. For the stack protector, we already attempt to disable it, but this fails on clang because the check is mixed with the gcc specific -fno-conserve-stack option. According to Andrey Ryabinin, that option is not even needed, dropping it here fixes the stackprotector issue. Link: http://lkml.kernel.org/r/20190722125139.1335385-1-arnd@arndb.de Link: https://lore.kernel.org/lkml/20190617123109.667090-1-arnd@arndb.de/t/ Link: https://lore.kernel.org/lkml/20190722091050.2188664-1-arnd@arndb.de/t/ Fixes: d08965a27e84 ("x86/uaccess, ubsan: Fix UBSAN vs. SMAP") Signed-off-by: Arnd Bergmann Reviewed-by: Andrey Ryabinin Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Dmitry Vyukov Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Kees Cook Cc: Matthew Wilcox Cc: Ard Biesheuvel Cc: Andy Shevchenko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/Makefile b/lib/Makefile index 095601ce371d..29c02a924973 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -279,7 +279,8 @@ obj-$(CONFIG_UCS2_STRING) += ucs2_string.o obj-$(CONFIG_UBSAN) += ubsan.o UBSAN_SANITIZE_ubsan.o := n -CFLAGS_ubsan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) +KASAN_SANITIZE_ubsan.o := n +CFLAGS_ubsan.o := $(call cc-option, -fno-stack-protector) $(DISABLE_STACKLEAK_PLUGIN) obj-$(CONFIG_SBITMAP) += sbitmap.o -- cgit v1.2.3 From ee38d94a0ad89890b770f6c876263cf9fcbfde84 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 2 Aug 2019 21:49:02 -0700 Subject: page flags: prioritize kasan bits over last-cpuid ARM64 randdconfig builds regularly run into a build error, especially when NUMA_BALANCING and SPARSEMEM are enabled but not SPARSEMEM_VMEMMAP: #error "KASAN: not enough bits in page flags for tag" The last-cpuid bits are already contitional on the available space, so the result of the calculation is a bit random on whether they were already left out or not. Adding the kasan tag bits before last-cpuid makes it much more likely to end up with a successful build here, and should be reliable for randconfig at least, as long as that does not randomize NR_CPUS or NODES_SHIFT but uses the defaults. In order for the modified check to not trigger in the x86 vdso32 code where all constants are wrong (building with -m32), enclose all the definitions with an #ifdef. [arnd@arndb.de: build fix] Link: http://lkml.kernel.org/r/CAK8P3a3Mno1SWTcuAOT0Wa9VS15pdU6EfnkxLbDpyS55yO04+g@mail.gmail.com Link: http://lkml.kernel.org/r/20190722115520.3743282-1-arnd@arndb.de Link: https://lore.kernel.org/lkml/20190618095347.3850490-1-arnd@arndb.de/ Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc") Signed-off-by: Arnd Bergmann Signed-off-by: Arnd Bergmann Reviewed-by: Andrey Konovalov Reviewed-by: Andrey Ryabinin Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc: Will Deacon Cc: Christoph Lameter Cc: Mark Rutland Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/mips/vdso/vdso.h | 1 + include/linux/page-flags-layout.h | 18 +++++++++++------- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/arch/mips/vdso/vdso.h b/arch/mips/vdso/vdso.h index 14b1931be69c..b65b169778e3 100644 --- a/arch/mips/vdso/vdso.h +++ b/arch/mips/vdso/vdso.h @@ -9,6 +9,7 @@ #if _MIPS_SIM != _MIPS_SIM_ABI64 && defined(CONFIG_64BIT) /* Building 32-bit VDSO for the 64-bit kernel. Fake a 32-bit Kconfig. */ +#define BUILD_VDSO32_64 #undef CONFIG_64BIT #define CONFIG_32BIT 1 #ifndef __ASSEMBLY__ diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h index 1dda31825ec4..71283739ffd2 100644 --- a/include/linux/page-flags-layout.h +++ b/include/linux/page-flags-layout.h @@ -32,6 +32,7 @@ #endif /* CONFIG_SPARSEMEM */ +#ifndef BUILD_VDSO32_64 /* * page->flags layout: * @@ -76,20 +77,22 @@ #define LAST_CPUPID_SHIFT 0 #endif -#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS +#ifdef CONFIG_KASAN_SW_TAGS +#define KASAN_TAG_WIDTH 8 +#else +#define KASAN_TAG_WIDTH 0 +#endif + +#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT+KASAN_TAG_WIDTH \ + <= BITS_PER_LONG - NR_PAGEFLAGS #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT #else #define LAST_CPUPID_WIDTH 0 #endif -#ifdef CONFIG_KASAN_SW_TAGS -#define KASAN_TAG_WIDTH 8 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH+LAST_CPUPID_WIDTH+KASAN_TAG_WIDTH \ > BITS_PER_LONG - NR_PAGEFLAGS -#error "KASAN: not enough bits in page flags for tag" -#endif -#else -#define KASAN_TAG_WIDTH 0 +#error "Not enough bits in page flags" #endif /* @@ -104,4 +107,5 @@ #define LAST_CPUPID_NOT_IN_PAGE_FLAGS #endif +#endif #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ -- cgit v1.2.3 From 315c69261dd3fa12dbc830d4fa00d1fad98d3b03 Mon Sep 17 00:00:00 2001 From: Paul Wise Date: Fri, 2 Aug 2019 21:49:05 -0700 Subject: coredump: split pipe command whitespace before expanding template Save the offsets of the start of each argument to avoid having to update pointers to each argument after every corename krealloc and to avoid having to duplicate the memory for the dump command. Executable names containing spaces were previously being expanded from %e or %E and then split in the middle of the filename. This is incorrect behaviour since an argument list can represent arguments with spaces. The splitting could lead to extra arguments being passed to the core dump handler that it might have interpreted as options or ignored completely. Core dump handlers that are not aware of this Linux kernel issue will be using %e or %E without considering that it may be split and so they will be vulnerable to processes with spaces in their names breaking their argument list. If their internals are otherwise well written, such as if they are written in shell but quote arguments, they will work better after this change than before. If they are not well written, then there is a slight chance of breakage depending on the details of the code but they will already be fairly broken by the split filenames. Core dump handlers that are aware of this Linux kernel issue will be placing %e or %E as the last item in their core_pattern and then aggregating all of the remaining arguments into one, separated by spaces. Alternatively they will be obtaining the filename via other methods. Both of these will be compatible with the new arrangement. A side effect from this change is that unknown template types (for example %z) result in an empty argument to the dump handler instead of the argument being dropped. This is a desired change as: It is easier for dump handlers to process empty arguments than dropped ones, especially if they are written in shell or don't pass each template item with a preceding command-line option in order to differentiate between individual template types. Most core_patterns in the wild do not use options so they can confuse different template types (especially numeric ones) if an earlier one gets dropped in old kernels. If the kernel introduces a new template type and a core_pattern uses it, the core dump handler might not expect that the argument can be dropped in old kernels. For example, this can result in security issues when %d is dropped in old kernels. This happened with the corekeeper package in Debian and resulted in the interface between corekeeper and Linux having to be rewritten to use command-line options to differentiate between template types. The core_pattern for most core dump handlers is written by the handler author who would generally not insert unknown template types so this change should be compatible with all the core dump handlers that exist. Link: http://lkml.kernel.org/r/20190528051142.24939-1-pabs3@bonedaddy.net Fixes: 74aadce98605 ("core_pattern: allow passing of arguments to user mode helper when core_pattern is a pipe") Signed-off-by: Paul Wise Reported-by: Jakub Wilk [https://bugs.debian.org/924398] Reported-by: Paul Wise [https://lore.kernel.org/linux-fsdevel/c8b7ecb8508895bf4adb62a748e2ea2c71854597.camel@bonedaddy.net/] Suggested-by: Jakub Wilk Acked-by: Neil Horman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/coredump.c | 44 +++++++++++++++++++++++++++++++++++++++----- 1 file changed, 39 insertions(+), 5 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index e42e17e55bfd..b1ea7dfbd149 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -187,11 +188,13 @@ put_exe_file: * name into corename, which must have space for at least * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. */ -static int format_corename(struct core_name *cn, struct coredump_params *cprm) +static int format_corename(struct core_name *cn, struct coredump_params *cprm, + size_t **argv, int *argc) { const struct cred *cred = current_cred(); const char *pat_ptr = core_pattern; int ispipe = (*pat_ptr == '|'); + bool was_space = false; int pid_in_pattern = 0; int err = 0; @@ -201,12 +204,35 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm) return -ENOMEM; cn->corename[0] = '\0'; - if (ispipe) + if (ispipe) { + int argvs = sizeof(core_pattern) / 2; + (*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL); + if (!(*argv)) + return -ENOMEM; + (*argv)[(*argc)++] = 0; ++pat_ptr; + } /* Repeat as long as we have more pattern to process and more output space */ while (*pat_ptr) { + /* + * Split on spaces before doing template expansion so that + * %e and %E don't get split if they have spaces in them + */ + if (ispipe) { + if (isspace(*pat_ptr)) { + was_space = true; + pat_ptr++; + continue; + } else if (was_space) { + was_space = false; + err = cn_printf(cn, "%c", '\0'); + if (err) + return err; + (*argv)[(*argc)++] = cn->used; + } + } if (*pat_ptr != '%') { err = cn_printf(cn, "%c", *pat_ptr++); } else { @@ -546,6 +572,8 @@ void do_coredump(const kernel_siginfo_t *siginfo) struct cred *cred; int retval = 0; int ispipe; + size_t *argv = NULL; + int argc = 0; struct files_struct *displaced; /* require nonrelative corefile path and be extra careful */ bool need_suid_safe = false; @@ -592,9 +620,10 @@ void do_coredump(const kernel_siginfo_t *siginfo) old_cred = override_creds(cred); - ispipe = format_corename(&cn, &cprm); + ispipe = format_corename(&cn, &cprm, &argv, &argc); if (ispipe) { + int argi; int dump_count; char **helper_argv; struct subprocess_info *sub_info; @@ -637,12 +666,16 @@ void do_coredump(const kernel_siginfo_t *siginfo) goto fail_dropcount; } - helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL); + helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv), + GFP_KERNEL); if (!helper_argv) { printk(KERN_WARNING "%s failed to allocate memory\n", __func__); goto fail_dropcount; } + for (argi = 0; argi < argc; argi++) + helper_argv[argi] = cn.corename + argv[argi]; + helper_argv[argi] = NULL; retval = -ENOMEM; sub_info = call_usermodehelper_setup(helper_argv[0], @@ -652,7 +685,7 @@ void do_coredump(const kernel_siginfo_t *siginfo) retval = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC); - argv_free(helper_argv); + kfree(helper_argv); if (retval) { printk(KERN_INFO "Core dump to |%s pipe failed\n", cn.corename); @@ -766,6 +799,7 @@ fail_dropcount: if (ispipe) atomic_dec(&core_dump_count); fail_unlock: + kfree(argv); kfree(cn.corename); coredump_finish(mm, core_dumped); revert_creds(old_cred); -- cgit v1.2.3 From 7b358c6f12dc82364f6d317f8c8f1d794adbc3f5 Mon Sep 17 00:00:00 2001 From: Ralph Campbell Date: Fri, 2 Aug 2019 21:49:08 -0700 Subject: mm/migrate.c: initialize pud_entry in migrate_vma() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls migrate_vma_collect() which initializes a struct mm_walk but didn't initialize mm_walk.pud_entry. (Found by code inspection) Use a C structure initialization to make sure it is set to NULL. Link: http://lkml.kernel.org/r/20190719233225.12243-1-rcampbell@nvidia.com Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with device memory") Signed-off-by: Ralph Campbell Reviewed-by: John Hubbard Reviewed-by: Andrew Morton Cc: "Jérôme Glisse" Cc: Mel Gorman Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 515718392b24..a42858d8e00b 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2340,16 +2340,13 @@ next: static void migrate_vma_collect(struct migrate_vma *migrate) { struct mmu_notifier_range range; - struct mm_walk mm_walk; - - mm_walk.pmd_entry = migrate_vma_collect_pmd; - mm_walk.pte_entry = NULL; - mm_walk.pte_hole = migrate_vma_collect_hole; - mm_walk.hugetlb_entry = NULL; - mm_walk.test_walk = NULL; - mm_walk.vma = migrate->vma; - mm_walk.mm = migrate->vma->vm_mm; - mm_walk.private = migrate; + struct mm_walk mm_walk = { + .pmd_entry = migrate_vma_collect_pmd, + .pte_hole = migrate_vma_collect_hole, + .vma = migrate->vma, + .mm = migrate->vma->vm_mm, + .private = migrate, + }; mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm, migrate->start, -- cgit v1.2.3 From aa4996b3af19f8535177ba21cb7241348a34fb94 Mon Sep 17 00:00:00 2001 From: Weitao Hou Date: Fri, 2 Aug 2019 21:49:12 -0700 Subject: mm/memory_hotplug.c: remove unneeded return for void function return is unneeded in void function Link: http://lkml.kernel.org/r/20190723130814.21826-1-houweitaoo@gmail.com Signed-off-by: Weitao Hou Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 2a9bbddb0e55..c73f09913165 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -132,7 +132,6 @@ static void release_memory_resource(struct resource *res) return; release_resource(res); kfree(res); - return; } #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE @@ -979,7 +978,6 @@ static void rollback_node_hotadd(int nid) arch_refresh_nodedata(nid, NULL); free_percpu(pgdat->per_cpu_nodestats); arch_free_nodedata(pgdat); - return; } -- cgit v1.2.3 From b59b1baab789eacdde809135542e3d4f256f6878 Mon Sep 17 00:00:00 2001 From: Chris Down Date: Fri, 2 Aug 2019 21:49:15 -0700 Subject: cgroup: kselftest: relax fs_spec checks On my laptop most memcg kselftests were being skipped because it claimed cgroup v2 hierarchy wasn't mounted, but this isn't correct. Instead, it seems current systemd HEAD mounts it with the name "cgroup2" instead of "cgroup": % grep cgroup /proc/mounts cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate 0 0 I can't think of a reason to need to check fs_spec explicitly since it's arbitrary, so we can just rely on fs_vfstype. After these changes, `make TARGETS=cgroup kselftest` actually runs the cgroup v2 tests in more cases. Link: http://lkml.kernel.org/r/20190723210737.GA487@chrisdown.name Signed-off-by: Chris Down Cc: Johannes Weiner Cc: Tejun Heo Cc: Roman Gushchin Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- tools/testing/selftests/cgroup/cgroup_util.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c index 4c223266299a..bdb69599c4bd 100644 --- a/tools/testing/selftests/cgroup/cgroup_util.c +++ b/tools/testing/selftests/cgroup/cgroup_util.c @@ -191,8 +191,7 @@ int cg_find_unified_root(char *root, size_t len) strtok(NULL, delim); strtok(NULL, delim); - if (strcmp(fs, "cgroup") == 0 && - strcmp(type, "cgroup2") == 0) { + if (strcmp(type, "cgroup2") == 0) { strncpy(root, mount, len); return 0; } -- cgit v1.2.3 From cbedfe11347fe418621bd188d58a206beb676218 Mon Sep 17 00:00:00 2001 From: Qian Cai Date: Fri, 2 Aug 2019 21:49:19 -0700 Subject: asm-generic: fix -Wtype-limits compiler warnings Commit d66acc39c7ce ("bitops: Optimise get_order()") introduced a compilation warning because "rx_frag_size" is an "ushort" while PAGE_SHIFT here is 16. The commit changed the get_order() to be a multi-line macro where compilers insist to check all statements in the macro even when __builtin_constant_p(rx_frag_size) will return false as "rx_frag_size" is a module parameter. In file included from ./arch/powerpc/include/asm/page_64.h:107, from ./arch/powerpc/include/asm/page.h:242, from ./arch/powerpc/include/asm/mmu.h:132, from ./arch/powerpc/include/asm/lppaca.h:47, from ./arch/powerpc/include/asm/paca.h:17, from ./arch/powerpc/include/asm/current.h:13, from ./include/linux/thread_info.h:21, from ./arch/powerpc/include/asm/processor.h:39, from ./include/linux/prefetch.h:15, from drivers/net/ethernet/emulex/benet/be_main.c:14: drivers/net/ethernet/emulex/benet/be_main.c: In function 'be_rx_cqs_create': ./include/asm-generic/getorder.h:54:9: warning: comparison is always true due to limited range of data type [-Wtype-limits] (((n) < (1UL << PAGE_SHIFT)) ? 0 : \ ^ drivers/net/ethernet/emulex/benet/be_main.c:3138:33: note: in expansion of macro 'get_order' adapter->big_page_size = (1 << get_order(rx_frag_size)) * PAGE_SIZE; ^~~~~~~~~ Fix it by moving all of this multi-line macro into a proper function, and killing __get_order() off. [akpm@linux-foundation.org: remove __get_order() altogether] [cai@lca.pw: v2] Link: http://lkml.kernel.org/r/1564000166-31428-1-git-send-email-cai@lca.pw Link: http://lkml.kernel.org/r/1563914986-26502-1-git-send-email-cai@lca.pw Fixes: d66acc39c7ce ("bitops: Optimise get_order()") Signed-off-by: Qian Cai Reviewed-by: Nathan Chancellor Cc: David S. Miller Cc: Arnd Bergmann Cc: David Howells Cc: Jakub Jelinek Cc: Nick Desaulniers Cc: Bill Wendling Cc: James Y Knight Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/getorder.h | 50 +++++++++++++++++------------------------- 1 file changed, 20 insertions(+), 30 deletions(-) diff --git a/include/asm-generic/getorder.h b/include/asm-generic/getorder.h index c64bea7a52be..e9f20b813a69 100644 --- a/include/asm-generic/getorder.h +++ b/include/asm-generic/getorder.h @@ -7,24 +7,6 @@ #include #include -/* - * Runtime evaluation of get_order() - */ -static inline __attribute_const__ -int __get_order(unsigned long size) -{ - int order; - - size--; - size >>= PAGE_SHIFT; -#if BITS_PER_LONG == 32 - order = fls(size); -#else - order = fls64(size); -#endif - return order; -} - /** * get_order - Determine the allocation order of a memory size * @size: The size for which to get the order @@ -43,19 +25,27 @@ int __get_order(unsigned long size) * to hold an object of the specified size. * * The result is undefined if the size is 0. - * - * This function may be used to initialise variables with compile time - * evaluations of constants. */ -#define get_order(n) \ -( \ - __builtin_constant_p(n) ? ( \ - ((n) == 0UL) ? BITS_PER_LONG - PAGE_SHIFT : \ - (((n) < (1UL << PAGE_SHIFT)) ? 0 : \ - ilog2((n) - 1) - PAGE_SHIFT + 1) \ - ) : \ - __get_order(n) \ -) +static inline __attribute_const__ int get_order(unsigned long size) +{ + if (__builtin_constant_p(size)) { + if (!size) + return BITS_PER_LONG - PAGE_SHIFT; + + if (size < (1UL << PAGE_SHIFT)) + return 0; + + return ilog2((size) - 1) - PAGE_SHIFT + 1; + } + + size--; + size >>= PAGE_SHIFT; +#if BITS_PER_LONG == 32 + return fls(size); +#else + return fls64(size); +#endif +} #endif /* __ASSEMBLY__ */ -- cgit v1.2.3 From 733d1d1a7745113e2b6a1761300e7e26b6eb6009 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Fri, 2 Aug 2019 21:49:22 -0700 Subject: lib/test_meminit.c: use GFP_ATOMIC in RCU critical section kmalloc() shouldn't sleep while in RCU critical section, therefore use GFP_ATOMIC instead of GFP_KERNEL. The bug was spotted by the 0day kernel testing robot. Link: http://lkml.kernel.org/r/20190725121703.210874-1-glider@google.com Fixes: 7e659650cbda ("lib: introduce test_meminit module") Signed-off-by: Alexander Potapenko Reviewed-by: Andrew Morton Reported-by: kernel test robot Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/test_meminit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/test_meminit.c b/lib/test_meminit.c index 62d19f270cad..9729f271d150 100644 --- a/lib/test_meminit.c +++ b/lib/test_meminit.c @@ -222,7 +222,7 @@ static int __init do_kmem_cache_size(size_t size, bool want_ctor, * Copy the buffer to check that it's not wiped on * free(). */ - buf_copy = kmalloc(size, GFP_KERNEL); + buf_copy = kmalloc(size, GFP_ATOMIC); if (buf_copy) memcpy(buf_copy, buf, size); -- cgit v1.2.3 From 14c5cebad510c2875ca525f36605b47058769670 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 2 Aug 2019 21:49:26 -0700 Subject: memremap: move from kernel/ to mm/ memremap.c implements MM functionality for ZONE_DEVICE, so it really should be in the mm/ directory, not the kernel/ one. Link: http://lkml.kernel.org/r/20190722094143.18387-1-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Anshuman Khandual Acked-by: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/Makefile | 1 - kernel/memremap.c | 405 ------------------------------------------------------ mm/Makefile | 1 + mm/memremap.c | 405 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 406 insertions(+), 406 deletions(-) delete mode 100644 kernel/memremap.c create mode 100644 mm/memremap.c diff --git a/kernel/Makefile b/kernel/Makefile index a8d923b5481b..ef0d95a190b4 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -111,7 +111,6 @@ obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o obj-$(CONFIG_TORTURE_TEST) += torture.o obj-$(CONFIG_HAS_IOMEM) += iomem.o -obj-$(CONFIG_ZONE_DEVICE) += memremap.o obj-$(CONFIG_RSEQ) += rseq.o obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o diff --git a/kernel/memremap.c b/kernel/memremap.c deleted file mode 100644 index 6ee03a816d67..000000000000 --- a/kernel/memremap.c +++ /dev/null @@ -1,405 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* Copyright(c) 2015 Intel Corporation. All rights reserved. */ -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -static DEFINE_XARRAY(pgmap_array); -#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) -#define SECTION_SIZE (1UL << PA_SECTION_SHIFT) - -#ifdef CONFIG_DEV_PAGEMAP_OPS -DEFINE_STATIC_KEY_FALSE(devmap_managed_key); -EXPORT_SYMBOL(devmap_managed_key); -static atomic_t devmap_managed_enable; - -static void devmap_managed_enable_put(void *data) -{ - if (atomic_dec_and_test(&devmap_managed_enable)) - static_branch_disable(&devmap_managed_key); -} - -static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap) -{ - if (!pgmap->ops || !pgmap->ops->page_free) { - WARN(1, "Missing page_free method\n"); - return -EINVAL; - } - - if (atomic_inc_return(&devmap_managed_enable) == 1) - static_branch_enable(&devmap_managed_key); - return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL); -} -#else -static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap) -{ - return -EINVAL; -} -#endif /* CONFIG_DEV_PAGEMAP_OPS */ - -static void pgmap_array_delete(struct resource *res) -{ - xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), - NULL, GFP_KERNEL); - synchronize_rcu(); -} - -static unsigned long pfn_first(struct dev_pagemap *pgmap) -{ - return PHYS_PFN(pgmap->res.start) + - vmem_altmap_offset(pgmap_altmap(pgmap)); -} - -static unsigned long pfn_end(struct dev_pagemap *pgmap) -{ - const struct resource *res = &pgmap->res; - - return (res->start + resource_size(res)) >> PAGE_SHIFT; -} - -static unsigned long pfn_next(unsigned long pfn) -{ - if (pfn % 1024 == 0) - cond_resched(); - return pfn + 1; -} - -#define for_each_device_pfn(pfn, map) \ - for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) - -static void dev_pagemap_kill(struct dev_pagemap *pgmap) -{ - if (pgmap->ops && pgmap->ops->kill) - pgmap->ops->kill(pgmap); - else - percpu_ref_kill(pgmap->ref); -} - -static void dev_pagemap_cleanup(struct dev_pagemap *pgmap) -{ - if (pgmap->ops && pgmap->ops->cleanup) { - pgmap->ops->cleanup(pgmap); - } else { - wait_for_completion(&pgmap->done); - percpu_ref_exit(pgmap->ref); - } -} - -static void devm_memremap_pages_release(void *data) -{ - struct dev_pagemap *pgmap = data; - struct device *dev = pgmap->dev; - struct resource *res = &pgmap->res; - unsigned long pfn; - int nid; - - dev_pagemap_kill(pgmap); - for_each_device_pfn(pfn, pgmap) - put_page(pfn_to_page(pfn)); - dev_pagemap_cleanup(pgmap); - - /* pages are dead and unused, undo the arch mapping */ - nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start))); - - mem_hotplug_begin(); - if (pgmap->type == MEMORY_DEVICE_PRIVATE) { - pfn = PHYS_PFN(res->start); - __remove_pages(page_zone(pfn_to_page(pfn)), pfn, - PHYS_PFN(resource_size(res)), NULL); - } else { - arch_remove_memory(nid, res->start, resource_size(res), - pgmap_altmap(pgmap)); - kasan_remove_zero_shadow(__va(res->start), resource_size(res)); - } - mem_hotplug_done(); - - untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res)); - pgmap_array_delete(res); - dev_WARN_ONCE(dev, pgmap->altmap.alloc, - "%s: failed to free all reserved pages\n", __func__); -} - -static void dev_pagemap_percpu_release(struct percpu_ref *ref) -{ - struct dev_pagemap *pgmap = - container_of(ref, struct dev_pagemap, internal_ref); - - complete(&pgmap->done); -} - -/** - * devm_memremap_pages - remap and provide memmap backing for the given resource - * @dev: hosting device for @res - * @pgmap: pointer to a struct dev_pagemap - * - * Notes: - * 1/ At a minimum the res and type members of @pgmap must be initialized - * by the caller before passing it to this function - * - * 2/ The altmap field may optionally be initialized, in which case - * PGMAP_ALTMAP_VALID must be set in pgmap->flags. - * - * 3/ The ref field may optionally be provided, in which pgmap->ref must be - * 'live' on entry and will be killed and reaped at - * devm_memremap_pages_release() time, or if this routine fails. - * - * 4/ res is expected to be a host memory range that could feasibly be - * treated as a "System RAM" range, i.e. not a device mmio range, but - * this is not enforced. - */ -void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) -{ - struct resource *res = &pgmap->res; - struct dev_pagemap *conflict_pgmap; - struct mhp_restrictions restrictions = { - /* - * We do not want any optional features only our own memmap - */ - .altmap = pgmap_altmap(pgmap), - }; - pgprot_t pgprot = PAGE_KERNEL; - int error, nid, is_ram; - bool need_devmap_managed = true; - - switch (pgmap->type) { - case MEMORY_DEVICE_PRIVATE: - if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) { - WARN(1, "Device private memory not supported\n"); - return ERR_PTR(-EINVAL); - } - if (!pgmap->ops || !pgmap->ops->migrate_to_ram) { - WARN(1, "Missing migrate_to_ram method\n"); - return ERR_PTR(-EINVAL); - } - break; - case MEMORY_DEVICE_FS_DAX: - if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || - IS_ENABLED(CONFIG_FS_DAX_LIMITED)) { - WARN(1, "File system DAX not supported\n"); - return ERR_PTR(-EINVAL); - } - break; - case MEMORY_DEVICE_DEVDAX: - case MEMORY_DEVICE_PCI_P2PDMA: - need_devmap_managed = false; - break; - default: - WARN(1, "Invalid pgmap type %d\n", pgmap->type); - break; - } - - if (!pgmap->ref) { - if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup)) - return ERR_PTR(-EINVAL); - - init_completion(&pgmap->done); - error = percpu_ref_init(&pgmap->internal_ref, - dev_pagemap_percpu_release, 0, GFP_KERNEL); - if (error) - return ERR_PTR(error); - pgmap->ref = &pgmap->internal_ref; - } else { - if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) { - WARN(1, "Missing reference count teardown definition\n"); - return ERR_PTR(-EINVAL); - } - } - - if (need_devmap_managed) { - error = devmap_managed_enable_get(dev, pgmap); - if (error) - return ERR_PTR(error); - } - - conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL); - if (conflict_pgmap) { - dev_WARN(dev, "Conflicting mapping in same section\n"); - put_dev_pagemap(conflict_pgmap); - error = -ENOMEM; - goto err_array; - } - - conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL); - if (conflict_pgmap) { - dev_WARN(dev, "Conflicting mapping in same section\n"); - put_dev_pagemap(conflict_pgmap); - error = -ENOMEM; - goto err_array; - } - - is_ram = region_intersects(res->start, resource_size(res), - IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); - - if (is_ram != REGION_DISJOINT) { - WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__, - is_ram == REGION_MIXED ? "mixed" : "ram", res); - error = -ENXIO; - goto err_array; - } - - pgmap->dev = dev; - - error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start), - PHYS_PFN(res->end), pgmap, GFP_KERNEL)); - if (error) - goto err_array; - - nid = dev_to_node(dev); - if (nid < 0) - nid = numa_mem_id(); - - error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0, - resource_size(res)); - if (error) - goto err_pfn_remap; - - mem_hotplug_begin(); - - /* - * For device private memory we call add_pages() as we only need to - * allocate and initialize struct page for the device memory. More- - * over the device memory is un-accessible thus we do not want to - * create a linear mapping for the memory like arch_add_memory() - * would do. - * - * For all other device memory types, which are accessible by - * the CPU, we do want the linear mapping and thus use - * arch_add_memory(). - */ - if (pgmap->type == MEMORY_DEVICE_PRIVATE) { - error = add_pages(nid, PHYS_PFN(res->start), - PHYS_PFN(resource_size(res)), &restrictions); - } else { - error = kasan_add_zero_shadow(__va(res->start), resource_size(res)); - if (error) { - mem_hotplug_done(); - goto err_kasan; - } - - error = arch_add_memory(nid, res->start, resource_size(res), - &restrictions); - } - - if (!error) { - struct zone *zone; - - zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; - move_pfn_range_to_zone(zone, PHYS_PFN(res->start), - PHYS_PFN(resource_size(res)), restrictions.altmap); - } - - mem_hotplug_done(); - if (error) - goto err_add_memory; - - /* - * Initialization of the pages has been deferred until now in order - * to allow us to do the work while not holding the hotplug lock. - */ - memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], - PHYS_PFN(res->start), - PHYS_PFN(resource_size(res)), pgmap); - percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap)); - - error = devm_add_action_or_reset(dev, devm_memremap_pages_release, - pgmap); - if (error) - return ERR_PTR(error); - - return __va(res->start); - - err_add_memory: - kasan_remove_zero_shadow(__va(res->start), resource_size(res)); - err_kasan: - untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res)); - err_pfn_remap: - pgmap_array_delete(res); - err_array: - dev_pagemap_kill(pgmap); - dev_pagemap_cleanup(pgmap); - return ERR_PTR(error); -} -EXPORT_SYMBOL_GPL(devm_memremap_pages); - -void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) -{ - devm_release_action(dev, devm_memremap_pages_release, pgmap); -} -EXPORT_SYMBOL_GPL(devm_memunmap_pages); - -unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) -{ - /* number of pfns from base where pfn_to_page() is valid */ - if (altmap) - return altmap->reserve + altmap->free; - return 0; -} - -void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) -{ - altmap->alloc -= nr_pfns; -} - -/** - * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn - * @pfn: page frame number to lookup page_map - * @pgmap: optional known pgmap that already has a reference - * - * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap - * is non-NULL but does not cover @pfn the reference to it will be released. - */ -struct dev_pagemap *get_dev_pagemap(unsigned long pfn, - struct dev_pagemap *pgmap) -{ - resource_size_t phys = PFN_PHYS(pfn); - - /* - * In the cached case we're already holding a live reference. - */ - if (pgmap) { - if (phys >= pgmap->res.start && phys <= pgmap->res.end) - return pgmap; - put_dev_pagemap(pgmap); - } - - /* fall back to slow path lookup */ - rcu_read_lock(); - pgmap = xa_load(&pgmap_array, PHYS_PFN(phys)); - if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) - pgmap = NULL; - rcu_read_unlock(); - - return pgmap; -} -EXPORT_SYMBOL_GPL(get_dev_pagemap); - -#ifdef CONFIG_DEV_PAGEMAP_OPS -void __put_devmap_managed_page(struct page *page) -{ - int count = page_ref_dec_return(page); - - /* - * If refcount is 1 then page is freed and refcount is stable as nobody - * holds a reference on the page. - */ - if (count == 1) { - /* Clear Active bit in case of parallel mark_page_accessed */ - __ClearPageActive(page); - __ClearPageWaiters(page); - - mem_cgroup_uncharge(page); - - page->pgmap->ops->page_free(page); - } else if (!count) - __put_page(page); -} -EXPORT_SYMBOL(__put_devmap_managed_page); -#endif /* CONFIG_DEV_PAGEMAP_OPS */ diff --git a/mm/Makefile b/mm/Makefile index 338e528ad436..d0b295c3b764 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -102,5 +102,6 @@ obj-$(CONFIG_FRAME_VECTOR) += frame_vector.o obj-$(CONFIG_DEBUG_PAGE_REF) += debug_page_ref.o obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o obj-$(CONFIG_PERCPU_STATS) += percpu-stats.o +obj-$(CONFIG_ZONE_DEVICE) += memremap.o obj-$(CONFIG_HMM_MIRROR) += hmm.o obj-$(CONFIG_MEMFD_CREATE) += memfd.o diff --git a/mm/memremap.c b/mm/memremap.c new file mode 100644 index 000000000000..6ee03a816d67 --- /dev/null +++ b/mm/memremap.c @@ -0,0 +1,405 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright(c) 2015 Intel Corporation. All rights reserved. */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_XARRAY(pgmap_array); +#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) +#define SECTION_SIZE (1UL << PA_SECTION_SHIFT) + +#ifdef CONFIG_DEV_PAGEMAP_OPS +DEFINE_STATIC_KEY_FALSE(devmap_managed_key); +EXPORT_SYMBOL(devmap_managed_key); +static atomic_t devmap_managed_enable; + +static void devmap_managed_enable_put(void *data) +{ + if (atomic_dec_and_test(&devmap_managed_enable)) + static_branch_disable(&devmap_managed_key); +} + +static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap) +{ + if (!pgmap->ops || !pgmap->ops->page_free) { + WARN(1, "Missing page_free method\n"); + return -EINVAL; + } + + if (atomic_inc_return(&devmap_managed_enable) == 1) + static_branch_enable(&devmap_managed_key); + return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL); +} +#else +static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap) +{ + return -EINVAL; +} +#endif /* CONFIG_DEV_PAGEMAP_OPS */ + +static void pgmap_array_delete(struct resource *res) +{ + xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), + NULL, GFP_KERNEL); + synchronize_rcu(); +} + +static unsigned long pfn_first(struct dev_pagemap *pgmap) +{ + return PHYS_PFN(pgmap->res.start) + + vmem_altmap_offset(pgmap_altmap(pgmap)); +} + +static unsigned long pfn_end(struct dev_pagemap *pgmap) +{ + const struct resource *res = &pgmap->res; + + return (res->start + resource_size(res)) >> PAGE_SHIFT; +} + +static unsigned long pfn_next(unsigned long pfn) +{ + if (pfn % 1024 == 0) + cond_resched(); + return pfn + 1; +} + +#define for_each_device_pfn(pfn, map) \ + for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) + +static void dev_pagemap_kill(struct dev_pagemap *pgmap) +{ + if (pgmap->ops && pgmap->ops->kill) + pgmap->ops->kill(pgmap); + else + percpu_ref_kill(pgmap->ref); +} + +static void dev_pagemap_cleanup(struct dev_pagemap *pgmap) +{ + if (pgmap->ops && pgmap->ops->cleanup) { + pgmap->ops->cleanup(pgmap); + } else { + wait_for_completion(&pgmap->done); + percpu_ref_exit(pgmap->ref); + } +} + +static void devm_memremap_pages_release(void *data) +{ + struct dev_pagemap *pgmap = data; + struct device *dev = pgmap->dev; + struct resource *res = &pgmap->res; + unsigned long pfn; + int nid; + + dev_pagemap_kill(pgmap); + for_each_device_pfn(pfn, pgmap) + put_page(pfn_to_page(pfn)); + dev_pagemap_cleanup(pgmap); + + /* pages are dead and unused, undo the arch mapping */ + nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start))); + + mem_hotplug_begin(); + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { + pfn = PHYS_PFN(res->start); + __remove_pages(page_zone(pfn_to_page(pfn)), pfn, + PHYS_PFN(resource_size(res)), NULL); + } else { + arch_remove_memory(nid, res->start, resource_size(res), + pgmap_altmap(pgmap)); + kasan_remove_zero_shadow(__va(res->start), resource_size(res)); + } + mem_hotplug_done(); + + untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res)); + pgmap_array_delete(res); + dev_WARN_ONCE(dev, pgmap->altmap.alloc, + "%s: failed to free all reserved pages\n", __func__); +} + +static void dev_pagemap_percpu_release(struct percpu_ref *ref) +{ + struct dev_pagemap *pgmap = + container_of(ref, struct dev_pagemap, internal_ref); + + complete(&pgmap->done); +} + +/** + * devm_memremap_pages - remap and provide memmap backing for the given resource + * @dev: hosting device for @res + * @pgmap: pointer to a struct dev_pagemap + * + * Notes: + * 1/ At a minimum the res and type members of @pgmap must be initialized + * by the caller before passing it to this function + * + * 2/ The altmap field may optionally be initialized, in which case + * PGMAP_ALTMAP_VALID must be set in pgmap->flags. + * + * 3/ The ref field may optionally be provided, in which pgmap->ref must be + * 'live' on entry and will be killed and reaped at + * devm_memremap_pages_release() time, or if this routine fails. + * + * 4/ res is expected to be a host memory range that could feasibly be + * treated as a "System RAM" range, i.e. not a device mmio range, but + * this is not enforced. + */ +void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) +{ + struct resource *res = &pgmap->res; + struct dev_pagemap *conflict_pgmap; + struct mhp_restrictions restrictions = { + /* + * We do not want any optional features only our own memmap + */ + .altmap = pgmap_altmap(pgmap), + }; + pgprot_t pgprot = PAGE_KERNEL; + int error, nid, is_ram; + bool need_devmap_managed = true; + + switch (pgmap->type) { + case MEMORY_DEVICE_PRIVATE: + if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) { + WARN(1, "Device private memory not supported\n"); + return ERR_PTR(-EINVAL); + } + if (!pgmap->ops || !pgmap->ops->migrate_to_ram) { + WARN(1, "Missing migrate_to_ram method\n"); + return ERR_PTR(-EINVAL); + } + break; + case MEMORY_DEVICE_FS_DAX: + if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || + IS_ENABLED(CONFIG_FS_DAX_LIMITED)) { + WARN(1, "File system DAX not supported\n"); + return ERR_PTR(-EINVAL); + } + break; + case MEMORY_DEVICE_DEVDAX: + case MEMORY_DEVICE_PCI_P2PDMA: + need_devmap_managed = false; + break; + default: + WARN(1, "Invalid pgmap type %d\n", pgmap->type); + break; + } + + if (!pgmap->ref) { + if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup)) + return ERR_PTR(-EINVAL); + + init_completion(&pgmap->done); + error = percpu_ref_init(&pgmap->internal_ref, + dev_pagemap_percpu_release, 0, GFP_KERNEL); + if (error) + return ERR_PTR(error); + pgmap->ref = &pgmap->internal_ref; + } else { + if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) { + WARN(1, "Missing reference count teardown definition\n"); + return ERR_PTR(-EINVAL); + } + } + + if (need_devmap_managed) { + error = devmap_managed_enable_get(dev, pgmap); + if (error) + return ERR_PTR(error); + } + + conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL); + if (conflict_pgmap) { + dev_WARN(dev, "Conflicting mapping in same section\n"); + put_dev_pagemap(conflict_pgmap); + error = -ENOMEM; + goto err_array; + } + + conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL); + if (conflict_pgmap) { + dev_WARN(dev, "Conflicting mapping in same section\n"); + put_dev_pagemap(conflict_pgmap); + error = -ENOMEM; + goto err_array; + } + + is_ram = region_intersects(res->start, resource_size(res), + IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); + + if (is_ram != REGION_DISJOINT) { + WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__, + is_ram == REGION_MIXED ? "mixed" : "ram", res); + error = -ENXIO; + goto err_array; + } + + pgmap->dev = dev; + + error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start), + PHYS_PFN(res->end), pgmap, GFP_KERNEL)); + if (error) + goto err_array; + + nid = dev_to_node(dev); + if (nid < 0) + nid = numa_mem_id(); + + error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0, + resource_size(res)); + if (error) + goto err_pfn_remap; + + mem_hotplug_begin(); + + /* + * For device private memory we call add_pages() as we only need to + * allocate and initialize struct page for the device memory. More- + * over the device memory is un-accessible thus we do not want to + * create a linear mapping for the memory like arch_add_memory() + * would do. + * + * For all other device memory types, which are accessible by + * the CPU, we do want the linear mapping and thus use + * arch_add_memory(). + */ + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { + error = add_pages(nid, PHYS_PFN(res->start), + PHYS_PFN(resource_size(res)), &restrictions); + } else { + error = kasan_add_zero_shadow(__va(res->start), resource_size(res)); + if (error) { + mem_hotplug_done(); + goto err_kasan; + } + + error = arch_add_memory(nid, res->start, resource_size(res), + &restrictions); + } + + if (!error) { + struct zone *zone; + + zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; + move_pfn_range_to_zone(zone, PHYS_PFN(res->start), + PHYS_PFN(resource_size(res)), restrictions.altmap); + } + + mem_hotplug_done(); + if (error) + goto err_add_memory; + + /* + * Initialization of the pages has been deferred until now in order + * to allow us to do the work while not holding the hotplug lock. + */ + memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], + PHYS_PFN(res->start), + PHYS_PFN(resource_size(res)), pgmap); + percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap)); + + error = devm_add_action_or_reset(dev, devm_memremap_pages_release, + pgmap); + if (error) + return ERR_PTR(error); + + return __va(res->start); + + err_add_memory: + kasan_remove_zero_shadow(__va(res->start), resource_size(res)); + err_kasan: + untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res)); + err_pfn_remap: + pgmap_array_delete(res); + err_array: + dev_pagemap_kill(pgmap); + dev_pagemap_cleanup(pgmap); + return ERR_PTR(error); +} +EXPORT_SYMBOL_GPL(devm_memremap_pages); + +void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) +{ + devm_release_action(dev, devm_memremap_pages_release, pgmap); +} +EXPORT_SYMBOL_GPL(devm_memunmap_pages); + +unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) +{ + /* number of pfns from base where pfn_to_page() is valid */ + if (altmap) + return altmap->reserve + altmap->free; + return 0; +} + +void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) +{ + altmap->alloc -= nr_pfns; +} + +/** + * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn + * @pfn: page frame number to lookup page_map + * @pgmap: optional known pgmap that already has a reference + * + * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap + * is non-NULL but does not cover @pfn the reference to it will be released. + */ +struct dev_pagemap *get_dev_pagemap(unsigned long pfn, + struct dev_pagemap *pgmap) +{ + resource_size_t phys = PFN_PHYS(pfn); + + /* + * In the cached case we're already holding a live reference. + */ + if (pgmap) { + if (phys >= pgmap->res.start && phys <= pgmap->res.end) + return pgmap; + put_dev_pagemap(pgmap); + } + + /* fall back to slow path lookup */ + rcu_read_lock(); + pgmap = xa_load(&pgmap_array, PHYS_PFN(phys)); + if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) + pgmap = NULL; + rcu_read_unlock(); + + return pgmap; +} +EXPORT_SYMBOL_GPL(get_dev_pagemap); + +#ifdef CONFIG_DEV_PAGEMAP_OPS +void __put_devmap_managed_page(struct page *page) +{ + int count = page_ref_dec_return(page); + + /* + * If refcount is 1 then page is freed and refcount is stable as nobody + * holds a reference on the page. + */ + if (count == 1) { + /* Clear Active bit in case of parallel mark_page_accessed */ + __ClearPageActive(page); + __ClearPageWaiters(page); + + mem_cgroup_uncharge(page); + + page->pgmap->ops->page_free(page); + } else if (!count) + __put_page(page); +} +EXPORT_SYMBOL(__put_devmap_managed_page); +#endif /* CONFIG_DEV_PAGEMAP_OPS */ -- cgit v1.2.3 From 7291edca20215dfdf0eb841881d63753448ef09c Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 2 Aug 2019 21:49:29 -0700 Subject: drivers/acpi/scan.c: document why we don't need the device_hotplug_lock Let's document why the lock is not needed in acpi_scan_init(), right now this is not really obvious. [akpm@linux-foundation.org: fix tpyo] Link: http://lkml.kernel.org/r/20190731135306.31524-1-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Michal Hocko Acked-by: Rafael J. Wysocki Cc: Oscar Salvador Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/acpi/scan.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 0e28270b0fd8..aad6be5c0af0 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -2204,6 +2204,12 @@ int __init acpi_scan_init(void) acpi_gpe_apply_masked_gpes(); acpi_update_all_gpes(); + /* + * Although we call __add_memory() that is documented to require the + * device_hotplug_lock, it is not necessary here because this is an + * early code when userspace or any other code path cannot trigger + * hotplug/hotunplug operations. + */ mutex_lock(&acpi_scan_lock); /* * Enumerate devices in the ACPI namespace. -- cgit v1.2.3