From: Bart Van Assche <bvanassche@acm.org>
To: Eric Dumazet <eric.dumazet@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org,
syzbot <syzbot+6f39a9deb697359fe520@syzkaller.appspotmail.com>,
syzkaller-bugs@googlegroups.com
Subject: Re: BUG: MAX_STACK_TRACE_ENTRIES too low! (2)
Date: Wed, 10 Jul 2019 12:09:34 -0700 [thread overview]
Message-ID: <cdfeb3f8-8dc5-aa60-2782-7b3c5110edf5@acm.org> (raw)
In-Reply-To: <47a9287d-1f02-95d5-a5cf-55f0c0d38378@gmail.com>
On 7/10/19 11:44 AM, Eric Dumazet wrote:
> If anything using workqueues in dynamically allocated objects can turn off lockdep,
> we have a serious issue.
As far as I know that issue is only hit by syzbot tests. Anyway, I see
two possible paths forward:
* Revert the patch that makes workqueues use dynamic lockdep keys and
thereby reintroduce the false positives that lockdep reports if
different workqueues share a lockdep key. I think there is agreement
that having to analyze lockdep false positives is annoying, time
consuming and something nobody likes.
* Modify lockdep such that space in its fixed size arrays that is no
longer in use gets reused. Since the stack traces saved in the
stack_trace[] array have a variable size that array will have to be
compacted to avoid fragmentation.
Did I overlook anything?
Bart.
next prev parent reply other threads:[~2019-07-10 19:09 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-29 10:42 syzbot
2019-03-30 11:10 ` syzbot
2019-03-30 21:58 ` syzbot
2019-03-31 2:17 ` Bart Van Assche
2019-07-10 5:30 ` Eric Biggers
2019-07-10 14:19 ` Bart Van Assche
2019-07-10 17:00 ` Eric Biggers
2019-07-10 17:21 ` Eric Biggers
2019-07-10 17:46 ` Bart Van Assche
2019-07-10 18:02 ` Eric Biggers
2019-07-10 18:36 ` Bart Van Assche
2019-07-10 18:44 ` Eric Dumazet
2019-07-10 19:09 ` Bart Van Assche [this message]
2019-07-10 20:47 ` Eric Dumazet
2019-07-10 21:23 ` Bart Van Assche
2019-07-10 22:09 ` Peter Zijlstra
2019-07-11 18:53 ` Bart Van Assche
2019-07-12 8:55 ` Peter Zijlstra
2019-07-12 23:03 ` Bart Van Assche
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