rcu: Protect uses of ->jiffies_stall with ACCESS_ONCE() (af952b91) · Commits · 戴 / test

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:

Himangi Saraogi <himangi774@gmail.com> Signed-off-by:

Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:

Josh Triplett <josh@joshtriplett.org>

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)

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