On Wed, Jan 24, 2018 at 04:15:49AM +0000, Sasha Levin wrote: > From: Jiang Biao <jiang.biao2@xxxxxxxxxx> > > [ Upstream commit d5dabd633922ac5ee5bcc67748f7defb8b211469 ] > > When running ltp stress test for 7*24 hours, vmscan occasionally emits > the following warning continuously: > > mb_cache_scan+0x0/0x3f0 negative objects to delete > nr=-9232265467809300450 > ... > > Tracing shows the freeable(mb_cache_count returns) is -1, which causes > the continuous accumulation and overflow of total_scan. > > This patch makes sure that mb_cache_count() cannot return a negative > value, which makes the mbcache shrinker more robust. > > Link: http://lkml.kernel.org/r/1511753419-52328-1-git-send-email-jiang.biao2@xxxxxxxxxx > Signed-off-by: Jiang Biao <jiang.biao2@xxxxxxxxxx> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxxxx> > Cc: <zhong.weidong@xxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> > --- > fs/mbcache.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/mbcache.c b/fs/mbcache.c > index c5bd19ffa326..35ab4187bfe1 100644 > --- a/fs/mbcache.c > +++ b/fs/mbcache.c > @@ -269,6 +269,9 @@ static unsigned long mb_cache_count(struct shrinker *shrink, > struct mb_cache *cache = container_of(shrink, struct mb_cache, > c_shrink); > > + /* Unlikely, but not impossible */ > + if (unlikely(cache->c_entry_count < 0)) > + return 0; > return cache->c_entry_count; > } This patch is broken and is reverted in linux-next, via ext4/dev: bbe45d2460da ("mbcache: revert "fs/mbcache.c: make count_objects() more robust"") Can you please update your "autosel" script/process/whatever to not select commits that are reverted?