From: Matthew Wilcox <willy@infradead.org>
To: syzbot <syzbot+51ce7a5794c3b12a70d1@syzkaller.appspotmail.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk
Subject: Re: WARNING: suspicious RCU usage in count
Date: Wed, 16 Dec 2020 20:55:36 +0000 [thread overview]
Message-ID: <20201216205536.GX2443@casper.infradead.org> (raw)
In-Reply-To: <0000000000009867cb05b699f5b6@google.com>
On Wed, Dec 16, 2020 at 11:34:10AM -0800, syzbot wrote:
> 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+51ce7a5794c3b12a70d1@syzkaller.appspotmail.com
>
> =============================
> WARNING: suspicious RCU usage
> 5.10.0-rc7-syzkaller #0 Not tainted
> -----------------------------
> kernel/sched/core.c:7270 Illegal context switch in RCU-bh read-side critical section!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 2, debug_locks = 0
> no locks held by udevd/9038.
>
> stack backtrace:
> CPU: 3 PID: 9038 Comm: udevd Not tainted 5.10.0-rc7-syzkaller #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x107/0x163 lib/dump_stack.c:118
> ___might_sleep+0x220/0x2b0 kernel/sched/core.c:7270
> count.constprop.0+0x164/0x270 fs/exec.c:449
> do_execveat_common+0x2fd/0x7c0 fs/exec.c:1893
> do_execve fs/exec.c:1983 [inline]
> __do_sys_execve fs/exec.c:2059 [inline]
> __se_sys_execve fs/exec.c:2054 [inline]
> __x64_sys_execve+0x8f/0xc0 fs/exec.c:2054
> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
This must be the victim of something else. There's no way this call
trace took the RCU read lock.
next prev parent reply other threads:[~2020-12-16 20:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-16 19:34 WARNING: suspicious RCU usage in count syzbot
2020-12-16 20:55 ` Matthew Wilcox [this message]
2020-12-17 8:26 ` Dmitry Vyukov
2020-12-17 15:19 ` Paul E. McKenney
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