From: Roland Dreier Date: Thu, 25 Sep 2008 22:28:08 +0000 (-0700) Subject: IPoIB: Fix crash when path record fails after path flush X-Git-Tag: v2.6.27-rc8~18 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=6ef190cc92e33565accff6a320f0e7d90480bfe7;p=linux-2.6-omap-h63xx.git IPoIB: Fix crash when path record fails after path flush Commit ee1e2c82 ("IPoIB: Refresh paths instead of flushing them on SM change events") changed how paths are flushed on an SM event. This change introduces a problem if the path record query triggered by fails, causing path->ah to become NULL. A later successful path query will then trigger WARN_ON() in path_rec_completion(), and crash because path->ah has already been freed, so the ipoib_put_ah() inside the lock in path_rec_completion() may actually drop the last reference (contrary to the comment that claims this is safe). Fix this by updating path->ah and freeing old_ah only when the path record query is successful. This prevents the neighbour AH and that path AH from getting out of sync. This fixes Reported-by: Rabah Salem Debugged-by: Eli Cohen Signed-off-by: Roland Dreier Signed-off-by: Linus Torvalds --- diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c index 1b1df5cc411..e9ca3cb57d5 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c @@ -404,7 +404,7 @@ static void path_rec_completion(int status, struct net_device *dev = path->dev; struct ipoib_dev_priv *priv = netdev_priv(dev); struct ipoib_ah *ah = NULL; - struct ipoib_ah *old_ah; + struct ipoib_ah *old_ah = NULL; struct ipoib_neigh *neigh, *tn; struct sk_buff_head skqueue; struct sk_buff *skb; @@ -428,12 +428,12 @@ static void path_rec_completion(int status, spin_lock_irqsave(&priv->lock, flags); - old_ah = path->ah; - path->ah = ah; - if (ah) { path->pathrec = *pathrec; + old_ah = path->ah; + path->ah = ah; + ipoib_dbg(priv, "created address handle %p for LID 0x%04x, SL %d\n", ah, be16_to_cpu(pathrec->dlid), pathrec->sl);