Commit bad6e139 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: get rid of signed overflow in check_cpu_stall() 



Signed integer overflow is undefined by the C standard, so move
calculations to unsigned.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent b554d7de

kernel/rcutree.c

+8 −5
Original line number Diff line number Diff line
@@ -581,21 +581,24 @@ static void print_cpu_stall(struct rcu_state *rsp) 


static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)

{

	long delta;

	unsigned long j;

	unsigned long js;

	struct rcu_node *rnp;



	if (rcu_cpu_stall_suppress)

		return;

	delta = jiffies - ACCESS_ONCE(rsp->jiffies_stall);

	j = ACCESS_ONCE(jiffies);

	js = ACCESS_ONCE(rsp->jiffies_stall);

	rnp = rdp->mynode;

	if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && delta >= 0) {

	if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) {



		/* We haven't checked in, so go dump stack. */

		print_cpu_stall(rsp);



	} else if (rcu_gp_in_progress(rsp) && delta >= RCU_STALL_RAT_DELAY) {

	} else if (rcu_gp_in_progress(rsp) &&

		   ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY)) {



		/* They had two time units to dump stack, so complain. */

		/* They had a few time units to dump stack, so complain. */

		print_other_cpu_stall(rsp);

	}

}