tree aabd6397c35daee20d579507f4c5256e88e813ec
parent a937536b868b8369b98967929045f1df54234323
author Ming Lei <ming.lei@canonical.com> 1363793124 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1363823622 -0700

sysfs: fix race between readdir and lseek

While readdir() is running, lseek() may set filp->f_pos as zero,
then may leave filp->private_data pointing to one sysfs_dirent
object without holding its reference counter, so the sysfs_dirent
object may be used after free in next readdir().

This patch holds inode->i_mutex to avoid the problem since
the lock is always held in readdir path.

Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>