From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Hillf Danton <hdanton@sina.com>,
Boqun Feng <boqun.feng@gmail.com>,
syzbot <syzbot+84ef57449019b1be878d@syzkaller.appspotmail.com>,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
tglx@linutronix.de, Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
rajatasthana4@gmail.com
Subject: Re: [syzbot] INFO: rcu detected stall in newstat
Date: Mon, 29 Nov 2021 15:59:32 +0100 [thread overview]
Message-ID: <YaTq1I82HEA/e6r6@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CACT4Y+ZxJUu+UrUpOwvcFOy2LubhP1HuCQybxaq-rrDsdO9bRg@mail.gmail.com>
On Mon, Nov 29, 2021 at 03:15:16PM +0100, Dmitry Vyukov wrote:
> Right, I missed the "preempt leak: 00000100 -> 00000101" warning. And
> before that there is also "WARNING: inconsistent lock state" warning.
> This reminds me of the issues we had with RCU/LOCKDEP before when an
> RCU warning disabled LOCKDEP tracking, as the result LOCKDEP missed
> part of events (e.g. tracked lock, but missed subsequent unlock) and
> due to races/ordering issues it mis-reported them as nonsensical
> reports.
You're talking about how debug_locks_off() is a hot-racy-mess? That only
matters if you're triggering stuff concurrently which *mostly* doesn't
happen.
I'm also not quite sure how to fix that without globally serializing
everything, which would be super unhappy.
next prev parent reply other threads:[~2021-11-29 18:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-03 7:55 syzbot
2021-11-27 17:11 ` syzbot
[not found] ` <20211128030309.1897-1-hdanton@sina.com>
2021-11-29 6:59 ` Dmitry Vyukov
[not found] ` <20211129131328.1960-1-hdanton@sina.com>
2021-11-29 14:15 ` Dmitry Vyukov
2021-11-29 14:59 ` Peter Zijlstra [this message]
2021-11-29 17:03 ` Dmitry Vyukov
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