From: Kirill Tkhai <ktk...@virtuozzo.com> There is a sad BUG introduced in patch adding SHRINKER_REGISTERING. shrinker_idr business is only for memcg-aware shrinkers. Only such type of shrinkers have id and they must be finaly installed via idr_replace() in this function. For !memcg-aware shrinkers we never initialize shrinker->id field.
But there are all types of shrinkers passed to idr_replace(), and every !memcg-aware shrinker with random ID (most probably, its id is 0) replaces memcg-aware shrinker pointed by the ID in IDR. This patch fixes the problem. Link: http://lkml.kernel.org/r/8ff8a793-8211-713a-4ed9-d6e52390c...@virtuozzo.com Fixes: 7e010df53c80 "mm: use special value SHRINKER_REGISTERING instead of list_empty() check" Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com> Reported-by: <syzbot+d5f648a1bfe156787...@syzkaller.appspotmail.com> Cc: Andrey Ryabinin <aryabi...@virtuozzo.com> Cc: Johannes Weiner <han...@cmpxchg.org> Cc: Josef Bacik <jba...@fb.com> Cc: Mel Gorman <mgor...@techsingularity.net> Cc: Michal Hocko <mho...@suse.com> Cc: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp> Cc: Shakeel Butt <shake...@google.com> Cc: <syzkaller-b...@googlegroups.com> Cc: Huang Ying <ying.hu...@intel.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> (cherry picked from commit 8df4a44cc46bf9dcfb80a37a59ae5dea2232dc58) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- mm/vmscan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 580c8c6843b9..52f5e9203ebe 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -376,7 +376,8 @@ void register_shrinker_prepared(struct shrinker *shrinker) down_write(&shrinker_rwsem); list_add_tail(&shrinker->list, &shrinker_list); #ifdef CONFIG_MEMCG_KMEM - idr_replace(&shrinker_idr, shrinker, shrinker->id); + if (shrinker->flags & SHRINKER_MEMCG_AWARE) + idr_replace(&shrinker_idr, shrinker, shrinker->id); #endif up_write(&shrinker_rwsem); } -- 2.24.1 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
