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From: Peter Zijlstra <peterz@infradead.org>
To: syzbot <syzbot+37fc8b84ffa2279d636d@syzkaller.appspotmail.com>
Cc: axboe@kernel.dk, christian@brauner.io, ebiederm@xmission.com,
	linux-kernel@vger.kernel.org, oleg@redhat.com, pcc@google.com,
	syzkaller-bugs@googlegroups.com, tglx@linutronix.de,
	Paul McKenney <paulmck@kernel.org>
Subject: Re: [syzbot] WARNING: suspicious RCU usage in get_signal
Date: Fri, 7 May 2021 10:37:56 +0200	[thread overview]
Message-ID: <YJT8ZPM5YGzX8Jtk@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <0000000000006540d705c1b013b5@google.com>

On Thu, May 06, 2021 at 02:34:27PM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    d2b6f8a1 Merge tag 'xfs-5.13-merge-3' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=123a56a5d00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=65c207250bba4efe
> dashboard link: https://syzkaller.appspot.com/bug?extid=37fc8b84ffa2279d636d
> userspace arch: i386
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+37fc8b84ffa2279d636d@syzkaller.appspotmail.com
> 
> =============================
> WARNING: suspicious RCU usage
> 5.12.0-syzkaller #0 Not tainted
> -----------------------------
> kernel/sched/core.c:8304 Illegal context switch in RCU-sched read-side critical section!
> 
> other info that might help us debug this:
> 
> 
> rcu_scheduler_active = 2, debug_locks = 0
> no locks held by syz-executor.4/10430.

Looks like this is a concurrent fail?, if !debug_locks (as per the above)
then RCU_LOCKDEP_WARN() should not trigger.

  reply	other threads:[~2021-05-07  8:38 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06 21:34 [syzbot] WARNING: suspicious RCU usage in get_signal syzbot
2021-05-07  8:37 ` Peter Zijlstra [this message]
2021-05-07  8:42   ` Dmitry Vyukov
2021-05-07 17:19     ` Paul E. McKenney
2021-05-08  5:03       ` Dmitry Vyukov
2021-05-08 22:59         ` Paul E. McKenney

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