From: Paul E. McKenney Date: Thu, 5 Jan 2012 22:44:39 +0000 (-0800) Subject: rcu: Add diagnostic for misaligned rcu_head structures X-Git-Tag: firefly_0821_release~3680^2~3355^2^2~44 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0bb7b59d6e2b8440cd7097097dd4bbfc4d76ed07;p=firefly-linux-kernel-4.4.55.git rcu: Add diagnostic for misaligned rcu_head structures The push for energy efficiency will require that RCU tag rcu_head structures to indicate whether or not their invocation is time critical. This tagging is best carried out in the bottom bits of the ->next pointers in the rcu_head structures. This tagging requires that the rcu_head structures be properly aligned, so this commit adds the required diagnostics. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 3cf713a724c1..570f7530f4b3 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1707,6 +1707,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), unsigned long flags; struct rcu_data *rdp; + WARN_ON_ONCE((unsigned long)head & 0x3); /* Misaligned rcu_head! */ debug_rcu_head_queue(head); head->func = func; head->next = NULL;