ocfs2: subsystem.su_mutex is required while accessing the item->ci_parent
The subsystem.su_mutex is required while accessing the item->ci_parent, otherwise, NULL pointer dereference to the item->ci_parent will be triggered in the following situation: add node delete node sys_write vfs_write configfs_write_file o2nm_node_store o2nm_node_local_write do_rmdir vfs_rmdir configfs_rmdir mutex_lock(&subsys->su_mutex); unlink_obj item->ci_group = NULL; item->ci_parent = NULL; to_o2nm_cluster_from_node node->nd_item.ci_parent->ci_parent BUG since of NULL pointer dereference to nd_item.ci_parent Moreover, the o2nm_cluster also should be protected by the subsystem.su_mutex. [alex.chen@huawei.com: v2] Link: http://lkml.kernel.org/r/59EEAA69.9080703@huawei.com Link: http://lkml.kernel.org/r/59E9B36A.10700@huawei.com Signed-off-by:Alex Chen <alex.chen@huawei.com> Reviewed-by:
Jun Piao <piaojun@huawei.com> Reviewed-by:
Joseph Qi <jiangqi903@gmail.com> Cc: Mark Fasheh <mfasheh@versity.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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3e4c56d4
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