From: Michal Hocko <mhocko@kernel.org>
To: syzbot <syzbot+bab151e82a4e973fa325@syzkaller.appspotmail.com>
Cc: cgroups@vger.kernel.org, dvyukov@google.com, hannes@cmpxchg.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
penguin-kernel@I-love.SAKURA.ne.jp,
syzkaller-bugs@googlegroups.com, vdavydov.dev@gmail.com
Subject: Re: WARNING in try_charge
Date: Mon, 6 Aug 2018 20:13:39 +0200 [thread overview]
Message-ID: <20180806181339.GD10003@dhcp22.suse.cz> (raw)
In-Reply-To: <20180806175627.GC10003@dhcp22.suse.cz>
I simply do not see how this is possible. Let's try with the following
extended debugging patch.
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 116b181bb646afedd770985de20a68721bdb2648
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4603ad75c9a9..e2dfdf4361ba 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1388,6 +1388,8 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
bool ret;
mutex_lock(&oom_lock);
+ pr_info("task=%s pid=%d invoked memcg oom killer. oom_victim=%d\n",
+ current->comm, current->pid, tsk_is_oom_victim(current));
ret = out_of_memory(&oc);
mutex_unlock(&oom_lock);
return ret;
@@ -2108,6 +2110,9 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
if (mem_cgroup_is_root(memcg))
return 0;
+ if (tsk_is_oom_victim(current))
+ pr_info("task=%s pid=%d charge for nr_pages=%d\n",
+ current->comm, current->pid, nr_pages);
retry:
if (consume_stock(memcg, nr_pages))
return 0;
@@ -2137,8 +2142,11 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
*/
if (unlikely(tsk_is_oom_victim(current) ||
fatal_signal_pending(current) ||
- current->flags & PF_EXITING))
+ current->flags & PF_EXITING)) {
+ pr_info("task=%s pid=%d charge bypass\n",
+ current->comm, current->pid);
goto force;
+ }
/*
* Prevent unbounded recursion when reclaim operations need to
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 104ef4a01a55..7d9adcde8cf6 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -692,6 +692,8 @@ static void mark_oom_victim(struct task_struct *tsk)
__thaw_task(tsk);
atomic_inc(&oom_victims);
trace_mark_victim(tsk->pid);
+ pr_info("task=%s pid=%d is oom victim now\n",
+ current->comm, current->pid);
}
/**
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-08-06 18:13 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-04 13:33 WARNING in try_charge syzbot
2018-08-04 13:45 ` Tetsuo Handa
2018-08-05 11:33 ` Tetsuo Handa
2018-08-05 8:14 ` syzbot
2018-08-06 9:15 ` Michal Hocko
2018-08-06 9:30 ` Dmitry Vyukov
2018-08-06 9:48 ` Michal Hocko
2018-08-06 10:34 ` Dmitry Vyukov
2018-08-06 11:02 ` Michal Hocko
2018-08-06 11:57 ` Dmitry Vyukov
2018-08-06 14:21 ` Michal Hocko
2018-08-06 14:58 ` Dmitry Vyukov
2018-08-06 17:30 ` Michal Hocko
2018-08-06 17:53 ` Dmitry Vyukov
2018-08-06 15:07 ` Dmitry Vyukov
2018-08-06 15:31 ` Johannes Weiner
2018-08-06 10:39 ` Dmitry Vyukov
2018-08-06 10:47 ` Tetsuo Handa
2018-08-06 11:09 ` Michal Hocko
2018-08-06 11:27 ` syzbot
2018-08-06 11:32 ` Michal Hocko
2018-08-06 11:58 ` Dmitry Vyukov
2018-08-06 14:41 ` Tetsuo Handa
2018-08-06 14:58 ` Michal Hocko
2018-08-06 15:12 ` Tetsuo Handa
2018-08-06 14:54 ` David Howells
2018-08-06 15:04 ` Tetsuo Handa
2018-08-06 11:00 ` syzbot
2018-08-06 15:32 ` Tetsuo Handa
2018-08-06 15:42 ` syzbot
2018-08-06 16:02 ` Tetsuo Handa
2018-08-06 17:44 ` Michal Hocko
2018-08-06 17:49 ` Dmitry Vyukov
2018-08-06 17:56 ` Michal Hocko
2018-08-06 18:13 ` Michal Hocko [this message]
2018-08-06 18:23 ` syzbot
2018-08-06 18:55 ` Michal Hocko
2018-08-06 19:12 ` syzbot
2018-08-06 19:45 ` Michal Hocko
2018-08-06 19:46 ` Michal Hocko
2018-08-07 11:18 ` Dmitry Vyukov
2018-08-07 11:25 ` Michal Hocko
2018-08-06 18:39 ` Michal Hocko
2018-08-06 20:26 ` Tetsuo Handa
2018-08-06 20:34 ` Michal Hocko
2018-08-06 20:46 ` Tetsuo Handa
2018-08-06 20:55 ` Michal Hocko
2018-08-06 21:50 ` Tetsuo Handa
2018-08-07 10:19 ` Tetsuo Handa
2018-08-09 13:57 ` Tetsuo Handa
2018-08-09 15:07 ` Michal Hocko
2018-08-09 21:05 ` Tetsuo Handa
2018-08-09 15:34 ` Johannes Weiner
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