[05/68] ocfs2_connection_find() returns pointer to bad structure

From: Greg KH
Date: Mon Feb 28 2011 - 11:52:59 EST

2.6.32-longterm review patch. If anyone has any objections, please let us know.


From: dann frazier <dann.frazier@xxxxxxxxxxxxx>

commit 226291aa4641fa13cb5dec3bcb3379faa83009e2 upstream.

If ocfs2_live_connection_list is empty, ocfs2_connection_find() will return
a pointer to the LIST_HEAD, cast as a ocfs2_live_connection. This can cause
an oops when ocfs2_control_send_down() dereferences c->oc_conn:

Call Trace:
[<ffffffffa00c2a3c>] ocfs2_control_message+0x28c/0x2b0 [ocfs2_stack_user]
[<ffffffffa00c2a95>] ocfs2_control_write+0x35/0xb0 [ocfs2_stack_user]
[<ffffffff81143a88>] vfs_write+0xb8/0x1a0
[<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[<ffffffff811442f1>] sys_write+0x51/0x80
[<ffffffff810121b2>] system_call_fastpath+0x16/0x1b

Fix by explicitly returning NULL if no match is found.

Signed-off-by: dann frazier <dann.frazier@xxxxxxxxxxxxx>
Signed-off-by: Joel Becker <joel.becker@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

fs/ocfs2/stack_user.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -191,7 +191,7 @@ static struct ocfs2_live_connection *ocf
return c;

- return c;
+ return NULL;


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