From: Yanmin Zhang <yanmin_zhang@xxxxxxxxxxxxxxx> Date: Wed, 23 May 2012 11:02:03 +0800 > 1) Why does free_fib_info call call_rcu instead of releasing fi directly? > I assume other cpu might be accessing it. nexthop_nh->nh_dev is in fi. > If other cpu are accessing it, here resetting to NULL would cause other > cpu panic. Because fib trie lookups are done with RCU locking, therefore we must use RCU freeing to release the object. What I was trying to impart to you is that removing the NULL assignment is wrong and that an alternative fix is warranted (hint: consider moving something into the RCU release). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/