The patch titled Subject: o2dlm: fix NULL pointer dereference in o2dlm_blocking_ast_wrapper has been removed from the -mm tree. Its filename was o2dlm-fix-null-pointer-dereference-in-o2dlm_blocking_ast_wrapper.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Srinivas Eeda <srinivas.eeda@xxxxxxxxxx> Subject: o2dlm: fix NULL pointer dereference in o2dlm_blocking_ast_wrapper A tiny race between BAST and unlock message causes the NULL dereference. A node sends an unlock request to master and receives a response. Before processing the response it receives a BAST from the master. Since both requests are processed by different threads it creates a race. While the BAST is being processed, lock can get freed by unlock code. This patch makes bast to return immediately if lock is found but unlock is pending. The code should handle this race. We also have to fix master node to skip sending BAST after receiving unlock message. Below is the crash stack BUG: unable to handle kernel NULL pointer dereference at 0000000000000048 IP: [<ffffffffa015e023>] o2dlm_blocking_ast_wrapper+0xd/0x16 [<ffffffffa034e3db>] dlm_do_local_bast+0x8e/0x97 [ocfs2_dlm] [<ffffffffa034f366>] dlm_proxy_ast_handler+0x838/0x87e [ocfs2_dlm] [<ffffffffa0308abe>] o2net_process_message+0x395/0x5b8 [ocfs2_nodemanager] [<ffffffffa030aac8>] o2net_rx_until_empty+0x762/0x90d [ocfs2_nodemanager] [<ffffffff81071802>] worker_thread+0x14d/0x1ed [akpm@xxxxxxxxxxxxxxxxxxxx: coding-style fixes] Signed-off-by: Srinivas Eeda <srinivas.eeda@xxxxxxxxxx> Reviewed-by: Mark Fasheh <mfasheh@xxxxxxx> Cc: Joel Becker <jlbec@xxxxxxxxxxxx> Cc: Joseph Qi <joseph.qi@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/ocfs2/dlm/dlmast.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff -puN fs/ocfs2/dlm/dlmast.c~o2dlm-fix-null-pointer-dereference-in-o2dlm_blocking_ast_wrapper fs/ocfs2/dlm/dlmast.c --- a/fs/ocfs2/dlm/dlmast.c~o2dlm-fix-null-pointer-dereference-in-o2dlm_blocking_ast_wrapper +++ a/fs/ocfs2/dlm/dlmast.c @@ -385,8 +385,12 @@ int dlm_proxy_ast_handler(struct o2net_m head = &res->granted; list_for_each_entry(lock, head, list) { - if (lock->ml.cookie == cookie) + /* if lock is found but unlock is pending ignore the bast */ + if (lock->ml.cookie == cookie) { + if (lock->unlock_pending) + break; goto do_ast; + } } mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, " _ Patches currently in -mm which might be from srinivas.eeda@xxxxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html