Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit af952b91 authored by Himangi Saraogi's avatar Himangi Saraogi Committed by Paul E. McKenney
Browse files

rcu: Protect uses of ->jiffies_stall with ACCESS_ONCE() 



Some of the accesses to the rcu_state structure's ->jiffies_stall
field are unprotected. This patch protects them with ACCESS_ONCE().
The following coccinelle script was used to acheive this:
/* coccinelle script to protect uses of ->jiffies_stall with ACCESS_ONCE() */
@@
identifier a;
@@
(
	ACCESS_ONCE(a->jiffies_stall)
|
-	a->jiffies_stall
+	ACCESS_ONCE(a->jiffies_stall)
)

Signed-off-by: default avatarHimangi Saraogi <himangi774@gmail.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent a235c091

kernel/rcu/tiny_plugin.h

+4 −4
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ static void check_cpu_stall(struct rcu_ctrlblk *rcp) 
		return;

	rcp->ticks_this_gp++;

	j = jiffies;

	js = rcp->jiffies_stall;

	js = ACCESS_ONCE(rcp->jiffies_stall);

	if (*rcp->curtail && ULONG_CMP_GE(j, js)) {

		pr_err("INFO: %s stall on CPU (%lu ticks this GP) idle=%llx (t=%lu jiffies q=%ld)\n",

		       rcp->name, rcp->ticks_this_gp, rcu_dynticks_nesting,
@@ -152,17 +152,17 @@ static void check_cpu_stall(struct rcu_ctrlblk *rcp) 
		dump_stack();

	}

	if (*rcp->curtail && ULONG_CMP_GE(j, js))

		rcp->jiffies_stall = jiffies +

		ACCESS_ONCE(rcp->jiffies_stall) = jiffies +

			3 * rcu_jiffies_till_stall_check() + 3;

	else if (ULONG_CMP_GE(j, js))

		rcp->jiffies_stall = jiffies + rcu_jiffies_till_stall_check();

		ACCESS_ONCE(rcp->jiffies_stall) = jiffies + rcu_jiffies_till_stall_check();

}



static void reset_cpu_stall_ticks(struct rcu_ctrlblk *rcp)

{

	rcp->ticks_this_gp = 0;

	rcp->gp_start = jiffies;

	rcp->jiffies_stall = jiffies + rcu_jiffies_till_stall_check();

	ACCESS_ONCE(rcp->jiffies_stall) = jiffies + rcu_jiffies_till_stall_check();

}



static void check_cpu_stalls(void)