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From: Miklos Szeredi <miklos@szeredi.hu>
To: Seth Forshee <seth.forshee@canonical.com>
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>
Subject: Re: [PATCH 1/3] fuse/dev: Fix unbalanced calls to kunmap_atomic() during splice I/O
Date: Fri, 18 Jul 2014 17:21:55 +0200	[thread overview]
Message-ID: <CAJfpegt7BRgnHZWR8TbgnXx7+Xey3CS98i1UUdjm4C2G1u6RGg@mail.gmail.com> (raw)
In-Reply-To: <1405365496-58404-2-git-send-email-seth.forshee@canonical.com>

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?

Thanks,
Miklos

  reply	other threads:[~2014-07-18 15:21 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 [this message]
2014-07-21 12:18     ` Seth Forshee
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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