From: Florian Fainelli Date: Mon, 5 Dec 2016 03:22:05 +0000 (-0800) Subject: net: ep93xx_eth: Do not crash unloading module X-Git-Tag: v3.2.85~28 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f05f3a72f505ed1ab46b6a50cb1e67c0cf975545;p=pandora-kernel.git net: ep93xx_eth: Do not crash unloading module commit c823abac17926767fb50175e098f087a6ac684c3 upstream. When we unload the ep93xx_eth, whether we have opened the network interface or not, we will either hit a kernel paging request error, or a simple NULL pointer de-reference because: - if ep93xx_open has been called, we have created a valid DMA mapping for ep->descs, when we call ep93xx_stop, we also call ep93xx_free_buffers, ep->descs now has a stale value - if ep93xx_open has not been called, we have a NULL pointer for ep->descs, so performing any operation against that address just won't work Fix this by adding a NULL pointer check for ep->descs which means that ep93xx_free_buffers() was able to successfully tear down the descriptors and free the DMA cookie as well. Fixes: 1d22e05df818 ("[PATCH] Cirrus Logic ep93xx ethernet driver") Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed