From: Thomas Gleixner <tglx@linutronix.de>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
syzbot <syzbot+7ffc7214b893651d52b8@syzkaller.appspotmail.com>,
syzkaller-bugs@googlegroups.com,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: WARNING in syscall_exit_to_user_mode
Date: Mon, 14 Sep 2020 22:22:59 +0200 [thread overview]
Message-ID: <87a6xsp0po.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <202009141304.811BAC4A0@keescook>
On Mon, Sep 14 2020 at 13:06, Kees Cook wrote:
> On Sun, Sep 13, 2020 at 09:54:34PM +0200, Thomas Gleixner wrote:
>> On Sat, Sep 12 2020 at 10:52, Kees Cook wrote:
>> >> ------------[ cut here ]------------
>> >> syscall 56 left IRQs disabled
>> >
>> > This WARN appears reachable. :)
>>
>> The above is hardly a problem of the new entry code. It's just detecting
>> the wreckage...
>
> Oh, well that's actually even better! :)
Of course I can't reproduce here ...
>> > I also see on the dashboard these other problems with the new entry
>> > code:
>>
>> > https://syzkaller.appspot.com/bug?extid=d4336c84ed0099fdbe47
>>
>> This one is also just the messenger. That's the
>>
>> lockdep_assert_irqs_disabled();
>>
>> in irqentry_exit() if I'm reading the reports correctly. That's a #PF
>> returning with interrupts enabled for whatever weird reason. Let me
>> stare at that...
>
> Cool; thanks.
No idea so far.
>> > https://syzkaller.appspot.com/bug?extid=c4af95386364bc59b13e
>>
>> This one is not a new entry code problem either:
>> [...]
>> The new entry code is just in the stack trace because that task was
>> preempted after a timer interrupt.
>
> This seems a bit like the first issue: it's just getting noticed now?
IIRC, I've seen such reports on older kernels as well, but not with the
new entry code in the traces.
Thanks,
tglx
next prev parent reply other threads:[~2020-09-14 20:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-11 10:39 WARNING in syscall_exit_to_user_mode syzbot
2020-09-12 17:52 ` Kees Cook
2020-09-13 19:54 ` Thomas Gleixner
2020-09-14 20:06 ` Kees Cook
2020-09-14 20:22 ` Thomas Gleixner [this message]
2020-09-13 19:40 ` Thomas Gleixner
2020-11-08 17:22 ` syzbot
2020-11-11 11:11 ` Dmitry Vyukov
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