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From: Dmitry Vyukov <dvyukov@google.com>
To: Jiri Kosina <jikos@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Konstantin Khlebnikov <koct9i@gmail.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>, Takashi Iwai <tiwai@suse.de>,
	syzkaller <syzkaller@googlegroups.com>,
	Kostya Serebryany <kcc@google.com>,
	Alexander Potapenko <glider@google.com>,
	Sasha Levin <sasha.levin@oracle.com>
Subject: Re: mm: uninterruptable tasks hanged on mmap_sem
Date: Tue, 2 Feb 2016 22:29:46 +0100	[thread overview]
Message-ID: <CACT4Y+ZYGHA5K0JPVOJa2bNiWgQPq1Z3QRjX70LZDH9bME9jnw@mail.gmail.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1602022222060.22727@cbobk.fhfr.pm>

On Tue, Feb 2, 2016 at 10:24 PM, Jiri Kosina <jikos@kernel.org> wrote:
> On Tue, 2 Feb 2016, Dmitry Vyukov wrote:
>
>> Original log from fuzzer contained the following WARNING in
>> mm/rmap.c:412. But when I tried to reproduce it, I hit these hanged
>> processes instead. I can't reliably detect what program triggered
>> what. So it may be related, or maybe a separate issue.
>>
>> ------------[ cut here ]------------
>> kernel BUG at mm/rmap.c:412!
>
> Are you by any chance in this test sending signals to the fuzzer?
>
> If so, the bug I just fixed in floppy driver can cause all kinds of memory
> corruptions in case you're running multithreaded accessess to /dev/fd0 and
> sending singals to the threads that are trying to access /dev/fd0 at the
> same time.
>
> Could you please double check that the other floppy fix I've sent you a
> couple days ago doesn't fix this as well? (this test makes sense only if
> signals are involved though).

I have "floppy: fix lock_fdc() signal handling" applied (the final,
second version).
The process is multithreaded and it can well receive SIGKILLs.

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  reply	other threads:[~2016-02-02 21:30 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-02 20:59 Dmitry Vyukov
2016-02-02 21:08 ` Jiri Kosina
2016-02-02 21:14   ` Dmitry Vyukov
2016-02-02 21:20     ` Dmitry Vyukov
2016-02-02 21:24       ` Jiri Kosina
2016-02-02 21:29         ` Dmitry Vyukov [this message]
2016-02-03 13:11 ` Jiri Kosina
2016-02-03 13:18   ` Dmitry Vyukov
2016-02-03 23:34 ` Jiri Kosina
2016-02-04 21:22 ` [PATCH] floppy: refactor open() flags handling (was Re: mm: uninterruptable tasks hanged on mmap_sem) Jiri Kosina
2016-02-05 13:43   ` Dmitry Vyukov
2016-02-05 13:51     ` [PATCH v2] " Jiri Kosina
2016-02-05 14:26       ` Dmitry Vyukov
2016-02-05 16:40         ` Jiri Kosina
2016-02-05 21:16           ` Dmitry Vyukov

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