From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
oleg@redhat.com, sbw@mit.edu,
Himangi Saraogi <himangi774@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 09/19] rcu: Protect uses of ->jiffies_stall with ACCESS_ONCE()
Date: Mon, 28 Apr 2014 16:56:22 -0700 [thread overview]
Message-ID: <1398729392-15087-9-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1398729392-15087-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: Himangi Saraogi <himangi774@gmail.com>
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>
---
kernel/rcu/tiny_plugin.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h
index 431528520562..858c56569127 100644
--- a/kernel/rcu/tiny_plugin.h
+++ b/kernel/rcu/tiny_plugin.h
@@ -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)
--
1.8.1.5
next prev parent reply other threads:[~2014-04-28 23:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-28 23:56 [PATCH tip/core/rcu 0/3] Miscellaneous fixes for 3.16 Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 01/19] rcu: Protect ->gp_flags accesses with ACCESS_ONCE() Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 02/19] rcu: Fix incorrect notes for code Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 03/19] rcu: Print negatives for stall-warning counter wraparound Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 04/19] rcu: Update cpu_needs_another_gp() for futures from non-NOCB CPUs Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 05/19] rcu: Remove unused rcu_data structure field Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 06/19] rcu: Protect uses of jiffies_stall field with ACCESS_ONCE() Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 07/19] rcu: Make callers awaken grace-period kthread Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 08/19] rcu: Remove "extern" from function declaration in include/linux/rcupdate.h Paul E. McKenney
2014-04-28 23:56 ` Paul E. McKenney [this message]
2014-04-28 23:56 ` [PATCH tip/core/rcu 10/19] rcu: Add event tracing to dyntick_save_progress_counter() Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 11/19] rcu: Replace NR_CPUS with nr_cpu_ids Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 12/19] rcu: Consolidate kfree_call_rcu() to use rcu_state pointer Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 13/19] rcu: Merge rcu_sched_force_quiescent_state() with rcu_force_quiescent_state() Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 14/19] rcu: Document RCU_INIT_POINTER()'s lack of ordering guarantees Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 15/19] rcu: Bind RCU grace-period kthreads if NO_HZ_FULL Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 16/19] rcu: Make large and small sysidle systems use same state machine Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 17/19] rcu: Remove duplicate resched_cpu() declaration Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 18/19] rcu: Replace __this_cpu_ptr() uses with raw_cpu_ptr() Paul E. McKenney
2014-04-28 23:56 ` [PATCH tip/core/rcu 19/19] softirq: A single rcu_bh_qs() call per softirq set is enough Paul E. McKenney
2014-04-29 3:23 ` [PATCH tip/core/rcu 0/3] Miscellaneous fixes for 3.16 Josh Triplett
2014-04-29 15:46 ` Paul E. McKenney
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