From: Seth Forshee <seth.forshee@canonical.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Kernel Mailing List <linux-kernel@vger.kernel.org>,
fuse-devel <fuse-devel@lists.sourceforge.net>,
lxc-devel@lists.linuxcontainers.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
Serge Hallyn <serge.hallyn@ubuntu.com>,
"Michael H. Warfield" <mhw@wittsend.com>,
Seth Forshee <seth.forshee@canonical.com>
Subject: Re: [PATCH 1/3] fuse/dev: Fix unbalanced calls to kunmap_atomic() during splice I/O
Date: Mon, 21 Jul 2014 07:18:54 -0500 [thread overview]
Message-ID: <20140721121854.GA111224@ubuntu-hedt> (raw)
In-Reply-To: <CAJfpegt7BRgnHZWR8TbgnXx7+Xey3CS98i1UUdjm4C2G1u6RGg@mail.gmail.com>
On Fri, Jul 18, 2014 at 05:21:55PM +0200, Miklos Szeredi wrote:
> On Mon, Jul 14, 2014 at 9:18 PM, Seth Forshee
> <seth.forshee@canonical.com> wrote:
> > fuse_copy_finish() assumes that mapaddr in fuse_copy_state refers
> > to a valid mapping if currbuf is non-NULL, but this isn't always
> > true when moving pages for splice I/O. This results in an
> > unbalanced call to kunmap_atomic() and thus an unbalanced
> > decrement of the preempt count. Avoid this by checking that
> > mapaddr is non-NULL before calling kunmap_atomic().
>
> I guess this is obsoleted by:
>
> c55a01d360af fuse: avoid scheduling while atomic
>
> which moves the kmap/kunmap closer to the actual use of the mapping.
>
> Can you please verify?
Yes, that commit does seem to fix the problem.
next prev parent reply other threads:[~2014-07-21 12:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-14 19:18 [PATCH 0/3] fuse: Allow mounts in containers Seth Forshee
2014-07-14 19:18 ` [PATCH 1/3] fuse/dev: Fix unbalanced calls to kunmap_atomic() during splice I/O Seth Forshee
2014-07-18 15:21 ` Miklos Szeredi
2014-07-21 12:18 ` Seth Forshee [this message]
2014-07-14 19:18 ` [PATCH 2/3] fuse: Translate pid making a request into the server's pid namespace Seth Forshee
2014-07-18 15:29 ` Miklos Szeredi
2014-07-14 19:18 ` [PATCH 3/3] fuse: Allow mounts from user namespaces Seth Forshee
2014-07-18 15:33 ` Miklos Szeredi
2014-07-21 12:47 ` Seth Forshee
2014-07-21 13:09 ` Miklos Szeredi
2014-07-21 14:34 ` Seth Forshee
2014-07-21 18:02 ` Eric W. Biederman
2014-07-22 3:30 ` Seth Forshee
2014-07-25 19:46 ` Seth Forshee
2014-07-26 16:27 ` Miklos Szeredi
2014-08-15 13:15 ` Seth Forshee
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