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From: Oleg Nesterov <oleg@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: syzbot <syzbot+b70f2aabc707c69c9239@syzkaller.appspotmail.com>,
	chanho.min@lge.com, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, pavel@ucw.cz,
	rafael.j.wysocki@intel.com, syzkaller-bugs@googlegroups.com,
	viro@zeniv.linux.org.uk
Subject: Re: WARNING: syz-executor still has locks held!
Date: Wed, 20 Mar 2019 14:24:11 +0100	[thread overview]
Message-ID: <20190320132410.GB21673@redhat.com> (raw)
In-Reply-To: <20190320131655.GA8696@dhcp22.suse.cz>

On 03/20, Michal Hocko wrote:
>
> Yes we do hold the cgred mutex while calling freezable_schedule but why
> are we getting a warning is not really clear to me. The task should be
> hidden from the freezer so why do we warn at all?

try_to_freeze() calls debug_check_no_locks_held() and this makes sense.

Another task can sleep waiting for the same lock; in this case
try_to_freeze_tasks() will fail but it won't blame the lock holder exactly
because it is "hidden from the freezer".

Oleg.


  reply	other threads:[~2019-03-20 13:24 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-24 17:40 WARNING: syz-executor still has locks held! syzbot
2019-03-20 12:24 ` syzbot
2019-03-20 13:16   ` Michal Hocko
2019-03-20 13:24     ` Oleg Nesterov [this message]
2019-03-20 13:29       ` Michal Hocko
2019-03-20 15:00         ` Oleg Nesterov
2019-03-20 15:12           ` Michal Hocko
2019-03-20 17:30             ` Oleg Nesterov
2019-03-20 19:45               ` Michal Hocko
2019-03-20 20:32                 ` Michal Hocko
2019-03-21 17:28                   ` Oleg Nesterov
2019-03-22 10:36                     ` Michal Hocko
2019-03-22 10:35               ` Pavel Machek
2019-03-20 13:18   ` Oleg Nesterov

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