From: Andy Lutomirski <luto@amacapital.net>
To: Stas Sergeev <stsp@list.ru>, Brian Gerst <brgerst@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Borislav Petkov <bp@alien8.de>,
Stas Sergeev <stsp@users.sourceforge.net>
Subject: Re: 4.3 regression: task_work corruption in vm86 mode?
Date: Fri, 30 Oct 2015 22:43:30 -0700 [thread overview]
Message-ID: <CALCETrWUmL5bPyxR0gvchtn433hdnSqOuRdBjFsqJqa_xbtBnw@mail.gmail.com> (raw)
In-Reply-To: <CALCETrUY51E290QYob+RMoKAzJCfo+y5-D2nithM1Bo2zOwoMw@mail.gmail.com>
On Fri, Oct 30, 2015 at 6:44 PM, Andy Lutomirski <luto@amacapital.net> wrote:
> Hi all-
>
> In 4.3-rc7, running dosemu2 (https://github.com/stsp/dosemu2/) oopses
> the system very quickly, as long as CONFIG_VM86=y. It blows up
> because snd_seq_delete_port walks ports_list_head, finds two valid
> ports, and then starts finding obviously invalid pointers in the list.
>
> git bisect blames:
>
> commit 5ed92a8ab71f8865ba07811429c988c72299b315
> Author: Brian Gerst <brgerst@gmail.com>
> Date: Wed Jul 29 01:41:19 2015 -0400
>
> x86/vm86: Use the normal pt_regs area for vm86
>
> I haven't spotted the problem yet. It seems to happen when
> task_work_run fires in get_signal, which happens before
> save_v86_state. I'm not entirely sure what causes task work to be
> scheduled at all while in v86 land. Could we somehow be processing
> task_work later than we should?
>
Nope, the bug has nothing to do with task_work. Patches sent.
--Andy
next prev parent reply other threads:[~2015-10-31 5:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-31 1:44 4.3 regression: task_work corruption in vm86 mode? Andy Lutomirski
2015-10-31 5:43 ` Andy Lutomirski [this message]
2015-10-31 11:50 ` Stas Sergeev
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