lkml.org 
[lkml]   [2007]   [Feb]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 09/18] IB/mad: Fix race between cancel and receive completion
-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Roland Dreier <rdreier@cisco.com>
When ib_cancel_mad() is called, it puts the canceled send on a list
and schedules a "flushed" callback from process context. However,
this leaves a window where a receive completion could be processed
before the send is fully flushed.

This is fine, except that ib_find_send_mad() will find the MAD and
return it to the receive processing, which results in the sender
getting both a successful receive and a "flushed" send completion for
the same request. Understandably, this confuses the sender, which is
expecting only one of these two callbacks, and leads to grief such as
a use-after-free in IPoIB.

Fix this by changing ib_find_send_mad() to return a send struct only
if the status is still successful (and not "flushed"). The search of
the send_list already had this check, so this patch just adds the same
check to the search of the wait_list.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
---
drivers/infiniband/core/mad.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-2.6.18.7.orig/drivers/infiniband/core/mad.c
+++ linux-2.6.18.7/drivers/infiniband/core/mad.c
@@ -1750,7 +1750,7 @@ ib_find_send_mad(struct ib_mad_agent_pri
*/
(is_direct(wc->recv_buf.mad->mad_hdr.mgmt_class) ||
rcv_has_same_gid(mad_agent_priv, wr, wc)))
- return wr;
+ return (wr->status == IB_WC_SUCCESS) ? wr : NULL;
}

/*
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-02-21 02:59    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site