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: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 0:08 INFO: rcu detected stall in shmem_fault 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
2018-10-11 6:37 ` 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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