From: Li Zefan <lizefan@huawei.com>
Date: Fri, 19 Apr 2013 06:09:52 +0000 (-0700)
Subject: cgroup: fix broken file xattrs
X-Git-Tag: omap-for-v3.10/dt-fixes-for-merge-window~124^2~5
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=712317ad97f41e738e1a19aa0a6392a78a84094e;p=pandora-kernel.git

cgroup: fix broken file xattrs

We should store file xattrs in struct cfent instead of struct cftype,
because cftype is a type while cfent is object instance of cftype.

For example each cgroup has a tasks file, and each tasks file is
associated with a uniq cfent, but all those files share the same
struct cftype.

Alexey Kodanev reported a crash, which can be reproduced:

  # mount -t cgroup -o xattr /sys/fs/cgroup
  # mkdir /sys/fs/cgroup/test
  # setfattr -n trusted.value -v test_value /sys/fs/cgroup/tasks
  # rmdir /sys/fs/cgroup/test
  # umount /sys/fs/cgroup
  oops!

In this case, simple_xattrs_free() will free the same struct simple_xattrs
twice.

tj: Dropped unused local variable @cft from cgroup_diput().

Cc: <stable@vger.kernel.org> # 3.8.x
Reported-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---

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