android_kernel_oneplus_msm8998/mm
Qian Cai cff989b79e mm/slub: fix a deadlock in show_slab_objects()
commit e4f8e513c3d353c134ad4eef9fd0bba12406c7c8 upstream.

A long time ago we fixed a similar deadlock in show_slab_objects() [1].
However, it is apparently due to the commits like 01fb58bcba63 ("slab:
remove synchronous synchronize_sched() from memcg cache deactivation
path") and 03afc0e25f ("slab: get_online_mems for
kmem_cache_{create,destroy,shrink}"), this kind of deadlock is back by
just reading files in /sys/kernel/slab which will generate a lockdep
splat below.

Since the "mem_hotplug_lock" here is only to obtain a stable online node
mask while racing with NUMA node hotplug, in the worst case, the results
may me miscalculated while doing NUMA node hotplug, but they shall be
corrected by later reads of the same files.

  WARNING: possible circular locking dependency detected
  ------------------------------------------------------
  cat/5224 is trying to acquire lock:
  ffff900012ac3120 (mem_hotplug_lock.rw_sem){++++}, at:
  show_slab_objects+0x94/0x3a8

  but task is already holding lock:
  b8ff009693eee398 (kn->count#45){++++}, at: kernfs_seq_start+0x44/0xf0

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (kn->count#45){++++}:
         lock_acquire+0x31c/0x360
         __kernfs_remove+0x290/0x490
         kernfs_remove+0x30/0x44
         sysfs_remove_dir+0x70/0x88
         kobject_del+0x50/0xb0
         sysfs_slab_unlink+0x2c/0x38
         shutdown_cache+0xa0/0xf0
         kmemcg_cache_shutdown_fn+0x1c/0x34
         kmemcg_workfn+0x44/0x64
         process_one_work+0x4f4/0x950
         worker_thread+0x390/0x4bc
         kthread+0x1cc/0x1e8
         ret_from_fork+0x10/0x18

  -> #1 (slab_mutex){+.+.}:
         lock_acquire+0x31c/0x360
         __mutex_lock_common+0x16c/0xf78
         mutex_lock_nested+0x40/0x50
         memcg_create_kmem_cache+0x38/0x16c
         memcg_kmem_cache_create_func+0x3c/0x70
         process_one_work+0x4f4/0x950
         worker_thread+0x390/0x4bc
         kthread+0x1cc/0x1e8
         ret_from_fork+0x10/0x18

  -> #0 (mem_hotplug_lock.rw_sem){++++}:
         validate_chain+0xd10/0x2bcc
         __lock_acquire+0x7f4/0xb8c
         lock_acquire+0x31c/0x360
         get_online_mems+0x54/0x150
         show_slab_objects+0x94/0x3a8
         total_objects_show+0x28/0x34
         slab_attr_show+0x38/0x54
         sysfs_kf_seq_show+0x198/0x2d4
         kernfs_seq_show+0xa4/0xcc
         seq_read+0x30c/0x8a8
         kernfs_fop_read+0xa8/0x314
         __vfs_read+0x88/0x20c
         vfs_read+0xd8/0x10c
         ksys_read+0xb0/0x120
         __arm64_sys_read+0x54/0x88
         el0_svc_handler+0x170/0x240
         el0_svc+0x8/0xc

  other info that might help us debug this:

  Chain exists of:
    mem_hotplug_lock.rw_sem --> slab_mutex --> kn->count#45

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(kn->count#45);
                                 lock(slab_mutex);
                                 lock(kn->count#45);
    lock(mem_hotplug_lock.rw_sem);

   *** DEADLOCK ***

  3 locks held by cat/5224:
   #0: 9eff00095b14b2a0 (&p->lock){+.+.}, at: seq_read+0x4c/0x8a8
   #1: 0eff008997041480 (&of->mutex){+.+.}, at: kernfs_seq_start+0x34/0xf0
   #2: b8ff009693eee398 (kn->count#45){++++}, at:
  kernfs_seq_start+0x44/0xf0

  stack backtrace:
  Call trace:
   dump_backtrace+0x0/0x248
   show_stack+0x20/0x2c
   dump_stack+0xd0/0x140
   print_circular_bug+0x368/0x380
   check_noncircular+0x248/0x250
   validate_chain+0xd10/0x2bcc
   __lock_acquire+0x7f4/0xb8c
   lock_acquire+0x31c/0x360
   get_online_mems+0x54/0x150
   show_slab_objects+0x94/0x3a8
   total_objects_show+0x28/0x34
   slab_attr_show+0x38/0x54
   sysfs_kf_seq_show+0x198/0x2d4
   kernfs_seq_show+0xa4/0xcc
   seq_read+0x30c/0x8a8
   kernfs_fop_read+0xa8/0x314
   __vfs_read+0x88/0x20c
   vfs_read+0xd8/0x10c
   ksys_read+0xb0/0x120
   __arm64_sys_read+0x54/0x88
   el0_svc_handler+0x170/0x240
   el0_svc+0x8/0xc

I think it is important to mention that this doesn't expose the
show_slab_objects to use-after-free.  There is only a single path that
might really race here and that is the slab hotplug notifier callback
__kmem_cache_shrink (via slab_mem_going_offline_callback) but that path
doesn't really destroy kmem_cache_node data structures.

[1] http://lkml.iu.edu/hypermail/linux/kernel/1101.0/02850.html

[akpm@linux-foundation.org: add comment explaining why we don't need mem_hotplug_lock]
Link: http://lkml.kernel.org/r/1570192309-10132-1-git-send-email-cai@lca.pw
Fixes: 01fb58bcba63 ("slab: remove synchronous synchronize_sched() from memcg cache deactivation path")
Fixes: 03afc0e25f ("slab: get_online_mems for kmem_cache_{create,destroy,shrink}")
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.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>
2019-10-29 09:13:28 +01:00
..
kasan kasan: fix shadow_size calculation error in kasan_module_alloc 2018-08-24 13:26:58 +02:00
backing-dev.c writeback: synchronize sync(2) against cgroup writeback membership switches 2019-06-11 12:23:41 +02:00
balloon_compaction.c virtio_balloon: fix race between migration and ballooning 2016-03-03 15:07:18 -08:00
bootmem.c bootmem: avoid freeing to bootmem after bootmem is done 2015-09-08 15:35:28 -07:00
cleancache.c cleancache: remove limit on the number of cleancache enabled filesystems 2015-04-14 16:49:03 -07:00
cma.c mm/cma.c: fail if fixed declaration can't be honored 2019-08-06 18:28:27 +02:00
cma.h mm: cma: mark cma_bitmap_maxno() inline in header 2015-08-14 15:56:32 -07:00
cma_debug.c mm/cma_debug.c: fix the break condition in cma_maxchunk_get() 2019-06-22 08:18:18 +02:00
compaction.c mm/compaction: pass only pageblock aligned range to pageblock_pfn_to_page 2018-01-17 09:35:26 +01:00
debug-pagealloc.c mm, hwpoison: fixup "mm: check the return value of lookup_page_ext for all call sites" 2017-11-24 11:26:29 +01:00
debug.c mm: get rid of vmacache_flush_all() entirely 2018-09-19 22:49:00 +02:00
dmapool.c mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd 2015-11-06 17:50:42 -08:00
early_ioremap.c mm/early_ioremap: Fix boot hang with earlyprintk=efi,keep 2018-02-25 11:03:41 +01:00
fadvise.c mm/fadvise.c: fix signed overflow UBSAN complaint 2018-09-15 09:40:38 +02:00
failslab.c mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM 2015-11-06 17:50:42 -08:00
filemap.c mm: filemap: avoid unnecessary calls to lock_page when waiting for IO to complete during a read 2018-05-26 08:48:54 +02:00
frame_vector.c mm: replace get_vaddr_frames() write/force parameters with gup_flags 2018-12-17 21:55:16 +01:00
frontswap.c frontswap: allow multiple backends 2015-06-24 17:49:45 -07:00
gup.c proc: do not access cmdline nor environ from file-backed areas 2018-12-17 21:55:17 +01:00
highmem.c mm/highmem: make kmap cache coloring aware 2014-08-06 18:01:22 -07:00
huge_memory.c mremap: properly flush TLB before releasing the page 2018-11-10 07:41:42 -08:00
hugetlb.c hugetlbfs: on restore reserve error path retain subpool reservation 2019-06-22 08:18:17 +02:00
hugetlb_cgroup.c mm: make compound_head() robust 2015-11-06 17:50:42 -08:00
hwpoison-inject.c hwpoison: use page_cgroup_ino for filtering by memcg 2015-09-10 13:29:01 -07:00
init-mm.c mm: Add a user_ns owner to mm_struct and fix ptrace permission checks 2017-01-06 11:16:11 +01:00
internal.h mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries 2017-08-11 09:08:50 -07:00
interval_tree.c mm: replace vma->sharead.linear with vma->shared 2015-02-10 14:30:31 -08:00
Kconfig mm: don't allow deferred pages with NEED_PER_CPU_KM 2018-05-26 08:48:55 +02:00
Kconfig.debug mm/debug_pagealloc: remove obsolete Kconfig options 2015-01-08 15:10:52 -08:00
kmemcheck.c mm/slab_common: move kmem_cache definition to internal header 2014-10-09 22:25:50 -04:00
kmemleak-test.c mm/kmemleak-test.c: use pr_fmt for logging 2014-06-06 16:08:18 -07:00
kmemleak.c mm/kmemleak.c: fix check for softirq context 2019-08-04 09:34:59 +02:00
ksm.c mm/ksm: fix interaction with THP 2018-05-30 07:49:08 +02:00
list_lru.c mm/list_lru.c: fix memory leak in __memcg_init_list_lru_node 2019-06-22 08:18:22 +02:00
maccess.c mm/maccess.c: actually return -EFAULT from strncpy_from_unsafe 2015-11-05 19:34:48 -08:00
madvise.c mm: madvise(MADV_DODUMP): allow hugetlbfs pages 2018-10-10 08:52:11 +02:00
Makefile media updates for v4.3-rc1 2015-09-11 16:42:39 -07:00
memblock.c mm: consider memblock reservations for deferred memory initialization sizing 2017-06-14 13:16:26 +02:00
memcontrol.c mm/memcontrol.c: fix use after free in mem_cgroup_iter() 2019-08-25 10:52:56 +02:00
memory-failure.c hwpoison, memcg: forcibly uncharge LRU pages 2018-01-31 12:06:09 +01:00
memory.c mm: replace access_remote_vm() write parameter with gup_flags 2018-12-17 21:55:17 +01:00
memory_hotplug.c mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone 2019-03-23 08:44:26 +01:00
mempolicy.c mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified 2019-04-27 09:33:47 +02:00
mempool.c mm/mempool: avoid KASAN marking mempool poison checks as use-after-free 2017-08-12 19:29:09 -07:00
memtest.c memtest: remove unused header files 2015-09-08 15:35:28 -07:00
migrate.c hugetlbfs: fix races and page leaks during migration 2019-03-23 08:44:23 +01:00
mincore.c mm/mincore.c: make mincore() more conservative 2019-06-11 12:23:36 +02:00
mlock.c mm: mlock: avoid increase mm->locked_vm on mlock() when already mlock2(,MLOCK_ONFAULT) 2018-12-13 09:21:33 +01:00
mm_init.c mm: meminit: remove mminit_verify_page_links 2015-06-30 19:44:56 -07:00
mmap.c coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping 2019-06-22 08:18:27 +02:00
mmu_context.c mm/mmu_context, sched/core: Fix mmu_context.h assumption 2017-12-25 14:22:09 +01:00
mmu_notifier.c mm/mmu_notifier: use hlist_add_head_rcu() 2019-08-04 09:34:59 +02:00
mmzone.c mm: microoptimize zonelist operations 2015-02-11 17:06:02 -08:00
mprotect.c x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings 2018-08-15 17:42:10 +02:00
mremap.c mremap: properly flush TLB before releasing the page 2018-11-10 07:41:42 -08:00
msync.c mm/msync: use offset_in_page macro 2015-11-05 19:34:48 -08:00
nobootmem.c mm: page_alloc: pass PFN to __free_pages_bootmem 2015-06-30 19:44:55 -07:00
nommu.c mm: replace access_remote_vm() write parameter with gup_flags 2018-12-17 21:55:17 +01:00
oom_kill.c mm, oom: fix use-after-free in oom_kill_process 2019-02-06 19:43:07 +01:00
page-writeback.c mm/page-writeback.c: don't break integrity writeback on ->writepage() error 2019-01-26 09:42:55 +01:00
page_alloc.c mm, page_alloc: do not break __GFP_THISNODE by zonelist reset 2018-07-11 16:03:51 +02:00
page_counter.c mm: page_counter: let page_counter_try_charge() return bool 2015-11-05 19:34:48 -08:00
page_ext.c mm/page_ext.c: fix an imbalance with kmemleak 2019-04-27 09:33:48 +02:00
page_idle.c mm/page_idle.c: fix oops because end_pfn is larger than max_pfn 2019-07-10 09:56:30 +02:00
page_io.c fs: use helper bio_add_page() instead of open coding on bi_io_vec 2015-08-13 12:32:00 -06:00
page_isolation.c mm: fix invalid node in alloc_migrate_target() 2016-04-20 15:41:53 +09:00
page_owner.c mm: check the return value of lookup_page_ext for all call sites 2017-11-24 08:32:25 +01:00
pagewalk.c mm/pagewalk.c: report holes in hugetlb ranges 2017-11-24 08:32:25 +01:00
percpu-km.c percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated 2014-09-02 14:46:05 -04:00
percpu-vm.c percpu: move region iterations out of pcpu_[de]populate_chunk() 2014-09-02 14:46:02 -04:00
percpu.c percpu: include linux/sched.h for cond_resched() 2018-05-16 10:06:46 +02:00
pgtable-generic.c mm,thp: khugepaged: call pte flush at the time of collapse 2016-02-25 12:01:23 -08:00
process_vm_access.c mm: replace get_user_pages_unlocked() write/force parameters with gup_flags 2018-12-17 21:55:16 +01:00
quicklist.c
readahead.c mm, fs: introduce mapping_gfp_constraint() 2015-11-06 17:50:42 -08:00
rmap.c mm/rmap: replace BUG_ON(anon_vma->degree) with VM_WARN_ON 2019-04-03 06:23:18 +02:00
shmem.c memfd: Fix locking when tagging pins 2019-10-29 09:13:23 +01:00
slab.c mm/slab.c: kmemleak no scan alien caches 2019-04-27 09:33:48 +02:00
slab.h slab/slub: adjust kmem_cache_alloc_bulk API 2015-11-22 11:58:44 -08:00
slab_common.c slub: do not merge cache if slub_debug contains a never-merge flag 2017-10-21 17:09:05 +02:00
slob.c slab/slub: adjust kmem_cache_alloc_bulk API 2015-11-22 11:58:44 -08:00
slub.c mm/slub: fix a deadlock in show_slab_objects() 2019-10-29 09:13:28 +01:00
sparse-vmemmap.c
sparse.c
swap.c mm: make compound_head() robust 2015-11-06 17:50:42 -08:00
swap_cgroup.c mm, swap_cgroup: reschedule when neeed in swap_cgroup_swapoff() 2017-07-05 14:37:15 +02:00
swap_state.c mm: swap: zswap: maybe_preload & refactoring 2015-09-08 15:35:28 -07:00
swapfile.c x86/speculation/l1tf: Limit swap file size to MAX_PA/2 2018-08-15 17:42:10 +02:00
truncate.c mm: cleancache: fix corruption on missed inode invalidation 2018-12-13 09:21:33 +01:00
userfaultfd.c userfaultfd: avoid mmap_sem read recursion in mcopy_atomic 2015-09-04 16:54:41 -07:00
util.c mm: replace get_user_pages_unlocked() write/force parameters with gup_flags 2018-12-17 21:55:16 +01:00
vmacache.c mm: get rid of vmacache_flush_all() entirely 2018-09-19 22:49:00 +02:00
vmalloc.c mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() 2019-08-25 10:52:44 +02:00
vmpressure.c mm: vmpressure: fix sending wrong events on underflow 2017-03-12 06:37:25 +01:00
vmscan.c mm: fix the NULL mapping case in __isolate_lru_page() 2018-06-06 16:46:23 +02:00
vmstat.c mm, vmstat: make quiet_vmstat lighter 2019-08-04 09:35:01 +02:00
workingset.c mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page() 2016-10-28 03:01:34 -04:00
zbud.c mm: zsmalloc: constify struct zs_pool name 2015-11-06 17:50:42 -08:00
zpool.c mm: zsmalloc: constify struct zs_pool name 2015-11-06 17:50:42 -08:00
zsmalloc.c zsmalloc: fix zs_can_compact() integer overflow 2016-05-18 17:06:44 -07:00
zswap.c zswap: re-check zswap_is_full() after do zswap_shrink() 2018-09-05 09:18:36 +02:00