From: Andrew Morton <akpm@linux-foundation.org>
To: Maxim Patlasov <mpatlasov@parallels.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>,
Roman Gushchin <klamm@yandex-team.ru>,
<fuse-devel@lists.sourceforge.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Miklos Szeredi <miklos@szeredi.hu>
Subject: Re: [fuse-devel] [PATCH] fuse: break infinite loop in fuse_fill_write_pages()
Date: Fri, 2 Oct 2015 15:04:40 -0700 [thread overview]
Message-ID: <20151002150440.e691f6c81619794f8a947263@linux-foundation.org> (raw)
In-Reply-To: <560EDAB1.5090605@parallels.com>
On Fri, 2 Oct 2015 12:27:45 -0700 Maxim Patlasov <mpatlasov@parallels.com> wrote:
> On 10/02/2015 04:21 AM, Konstantin Khlebnikov wrote:
> > Bump. Add more peopple in CC.
> >
> > On Mon, Sep 21, 2015 at 1:02 PM, Roman Gushchin <klamm@yandex-team.ru> wrote:
> >> I got a report about unkillable task eating CPU. Thge further
> >> investigation shows, that the problem is in the fuse_fill_write_pages()
> >> function. If iov's first segment has zero length, we get an infinite
> >> loop, because we never reach iov_iter_advance() call.
>
> iov_iter_copy_from_user_atomic() eventually calls iterate_iovec(). The
> latter silently consumes zero-length iov. So I don't think "iov's first
> segment has zero length" can cause infinite loop.
I'm suspecting it got stuck because local variable `bytes' is zero, so
the code does `goto again' repeatedly.
Or maybe not. A more complete description of the bug would help.
next prev parent reply other threads:[~2015-10-02 22:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-21 10:02 Roman Gushchin
2015-10-02 11:21 ` Konstantin Khlebnikov
2015-10-02 19:27 ` [fuse-devel] " Maxim Patlasov
2015-10-02 22:04 ` Andrew Morton [this message]
2015-10-03 1:58 ` Konstantin Khlebnikov
2015-10-05 18:37 ` Maxim Patlasov
2015-10-12 13:33 ` [PATCH v2] " Roman Gushchin
2015-11-10 14:41 ` Miklos Szeredi
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