From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> To: syzbot <syzbot+77e6b28a7a7106ad0def@syzkaller.appspotmail.com>, hannes@cmpxchg.org, mhocko@kernel.org Cc: akpm@linux-foundation.org, guro@fb.com, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rientjes@google.com, syzkaller-bugs@googlegroups.com, yang.s@alibaba-inc.com Subject: Re: INFO: rcu detected stall in shmem_fault Date: Wed, 10 Oct 2018 09:12:45 +0900 [thread overview] Message-ID: <201810100012.w9A0Cjtn047782@www262.sakura.ne.jp> (raw) In-Reply-To: <000000000000dc48d40577d4a587@google.com> syzbot is hitting RCU stall due to memcg-OOM event. https://syzkaller.appspot.com/bug?id=4ae3fff7fcf4c33a47c1192d2d62d2e03efffa64 What should we do if memcg-OOM found no killable task because the allocating task was oom_score_adj == -1000 ? Flooding printk() until RCU stall watchdog fires (which seems to be caused by commit 3100dab2aa09dc6e ("mm: memcontrol: print proper OOM header when no eligible victim left") because syzbot was terminating the test upon WARN(1) removed by that commit) is not a good behavior. syz-executor0 invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), nodemask=(null), order=0, oom_score_adj=-1000 syz-executor0 cpuset=syz0 mems_allowed=0 CPU: 0 PID: 2050 Comm: syz-executor0 Not tainted 4.19.0-rc7-next-20181009+ #90 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: (...snipped...) Memory limit reached of cgroup /syz0 memory: usage 205168kB, limit 204800kB, failcnt 6909 memory+swap: usage 0kB, limit 9007199254740988kB, failcnt 0 kmem: usage 0kB, limit 9007199254740988kB, failcnt 0 Memory cgroup stats for /syz0: cache:680KB rss:176336KB rss_huge:163840KB shmem:740KB mapped_file:660KB dirty:0KB writeback:0KB swap:0KB inactive_anon:712KB active_anon:176448KB inactive_file:0KB active_file:4KB unevictable:0KB Out of memory and no killable processes...
next prev parent reply other threads:[~2018-10-10 0:12 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-10 0:08 syzbot 2018-10-10 0:12 ` Tetsuo Handa [this message] 2018-10-10 4:11 ` David Rientjes 2018-10-10 7:55 ` Dmitry Vyukov 2018-10-10 9:13 ` Michal Hocko 2018-10-10 9:33 ` Dmitry Vyukov 2018-10-10 9:02 ` Michal Hocko 2018-10-10 8:59 ` Michal Hocko 2018-10-10 10:43 ` Tetsuo Handa 2018-10-10 11:35 ` Michal Hocko 2018-10-10 11:48 ` Sergey Senozhatsky 2018-10-10 12:25 ` Michal Hocko 2018-10-10 12:29 ` Dmitry Vyukov 2018-10-10 12:36 ` Dmitry Vyukov 2018-10-10 13:10 ` Tetsuo Handa 2018-10-10 13:17 ` Dmitry Vyukov 2018-10-11 1:17 ` Sergey Senozhatsky 2018-10-10 15:17 ` Sergey Senozhatsky 2018-10-10 14:19 ` Tetsuo Handa 2018-10-10 15:11 ` [RFC PATCH] memcg, oom: throttle dump_header for memcg ooms without eligible tasks Michal Hocko 2018-10-10 15:11 ` Michal Hocko 2018-10-11 6:37 ` Tetsuo Handa 2018-10-11 6:37 ` Tetsuo Handa 2018-10-12 10:47 ` Tetsuo Handa 2018-10-12 10:47 ` Tetsuo Handa 2018-10-12 11:20 ` Johannes Weiner 2018-10-12 12:08 ` Michal Hocko 2018-10-12 12:10 ` Tetsuo Handa 2018-10-12 12:41 ` Johannes Weiner 2018-10-12 12:58 ` Tetsuo Handa 2018-10-13 11:09 ` Tetsuo Handa 2018-10-13 11:22 ` Johannes Weiner 2018-10-13 11:28 ` Tetsuo Handa 2018-10-15 8:19 ` Michal Hocko 2018-10-15 10:57 ` Tetsuo Handa 2018-10-15 11:24 ` Michal Hocko 2018-10-15 12:47 ` Tetsuo Handa 2018-10-15 13:35 ` Michal Hocko 2018-10-16 0:55 ` Tetsuo Handa 2018-10-16 9:20 ` Michal Hocko 2018-10-16 11:05 ` Tetsuo Handa 2018-10-16 11:17 ` Michal Hocko
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