On Wed, Oct 17, 2012 at 05:45:36PM +0900, Jun'ichi Nomura wrote: > blk_put_rl() does not call blkg_put() for q->root_rl because we > don't take request list reference on q->root_blkg. > However, if root_blkg is once attached then detached (freed), > blk_put_rl() is confused by the bogus pointer in q->root_blkg. > > For example, with !CONFIG_BLK_DEV_THROTTLING && > CONFIG_CFQ_GROUP_IOSCHED, > switching IO scheduler from cfq to deadline will cause system stall > after the following warning with 3.6: ... > This patch clears q->root_blkg and q->root_rl.blkg when root blkg > is destroyed. > > Signed-off-by: Jun'ichi Nomura <j-nom...@ce.jp.nec.com> > Acked-by: Vivek Goyal <vgo...@redhat.com> > Cc: Tejun Heo <t...@kernel.org> > Cc: Jens Axboe <ax...@kernel.dk>
Acked-by: Tejun Heo <t...@kernel.org> Jens, this one needs Cc: stable. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/