netdev - [PATCH 3/5] sched/preempt: cond_resched_softirq() must check for softirq

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Date:	Wed, 15 Jun 2016 15:42:04 +0200
From:	Paolo Abeni <pabeni@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>,
	netdev@...r.kernel.org
Subject: [PATCH 3/5] sched/preempt: cond_resched_softirq() must check for softirq

Currently cond_resched_softirq() fails to reschedule if there
are pending softirq but no other running process. This happens
i.e. when receiving an interrupt with local bh disabled.

Reported-by: Eric Dumazet <eric.dumazet@...il.com>
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@...essinduktion.org>
---
 kernel/sched/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7f2cae4..788625f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4837,7 +4837,8 @@ int __sched __cond_resched_softirq(void)
 {
 	BUG_ON(!in_softirq());
 
-	if (should_resched(SOFTIRQ_DISABLE_OFFSET)) {
+	if (should_resched(SOFTIRQ_DISABLE_OFFSET) ||
+	    local_softirq_pending()) {
 		local_bh_enable();
 		preempt_schedule_common();
 		local_bh_disable();
-- 
1.8.3.1