From: Roland Dreier Date: Mon, 13 Nov 2006 17:38:07 +0000 (-0800) Subject: IB/mad: Fix race between cancel and receive completion X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=39798695b4bcc7b145f8910ca56195808d3a7637;p=linux-beck.git IB/mad: Fix race between cancel and receive completion 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 --- diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c index 493f4c65c7a2..a72bcea46ff6 100644 --- a/drivers/infiniband/core/mad.c +++ b/drivers/infiniband/core/mad.c @@ -1750,7 +1750,7 @@ ib_find_send_mad(struct ib_mad_agent_private *mad_agent_priv, */ (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; } /*