From: Patrick McHardy Date: Thu, 30 Aug 2012 07:01:30 +0000 (+0000) Subject: IPoIB: Fix use-after-free of multicast object X-Git-Tag: omap-for-v3.7-rc1/fixes-cpufreq-signed~42^2^3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bea1e22df494a729978e7f2c54f7bda328f74bc3;p=pandora-kernel.git IPoIB: Fix use-after-free of multicast object Fix a crash in ipoib_mcast_join_task(). (with help from Or Gerlitz) Commit c8c2afe360b7 ("IPoIB: Use rtnl lock/unlock when changing device flags") added a call to rtnl_lock() in ipoib_mcast_join_task(), which is run from the ipoib_workqueue, and hence the workqueue can't be flushed from the context of ipoib_stop(). In the current code, ipoib_stop() (which doesn't flush the workqueue) calls ipoib_mcast_dev_flush(), which goes and deletes all the multicast entries. This takes place without any synchronization with a possible running instance of ipoib_mcast_join_task() for the same ipoib device, leading to a crash due to NULL pointer dereference. Fix this by making sure that the workqueue is flushed before ipoib_mcast_dev_flush() is called. To make that possible, we move the RTNL-lock wrapped code to ipoib_mcast_join_finish(). Signed-off-by: Patrick McHardy Cc: Signed-off-by: Roland Dreier --- Reading git-diff-tree failed