From: Tejun Heo <tj@kernel.org>
Date: Tue, 10 Dec 2013 15:22:30 +0000 (-0500)
Subject: sysfs: fix use-after-free in sysfs_kill_sb()
X-Git-Tag: v3.14-rc1~151^2~57
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a7560a0132cfc93b25d2df1d277a078a05220cf4;p=pandora-kernel.git

sysfs: fix use-after-free in sysfs_kill_sb()

While restructuring the [u]mount path, 4b93dc9b1c68 ("sysfs, kernfs:
prepare mount path for kernfs") incorrectly updated sysfs_kill_sb() so
that it first kills super_block and then tries to dereference its
namespace tag to drop it.  Fix it by caching namespace tag before
killing the superblock and then drop the cached namespace tag.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Tested-by: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/g/20131205031051.GC5135@yliu-dev.sh.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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