[PATCH RT 5/8] arm: lazy preempt: correct resched condition

From	Steven Rostedt <rostedt@goodmis.org>
Newsgroups	linux.kernel
Subject	[PATCH RT 5/8] arm: lazy preempt: correct resched condition
Date	2016-07-12 19:00 +0200
Message-ID	<rU9cm-7AG-19@gated-at.bofh.it> (permalink)
References	<rU9cm-7AG-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

3.10.102-rt113-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

If we get out of preempt_schedule_irq() then we check for NEED_RESCHED
and call the former function again if set because the preemption counter
has be zero at this point.
However the counter for lazy-preempt might not be zero therefore we have
to check the counter before looking at the need_resched_lazy flag.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/arm/kernel/entry-armv.S | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 9b51e3faff52..06be94212de9 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -234,7 +234,11 @@ svc_preempt:
 	bne	1b
 	tst	r0, #_TIF_NEED_RESCHED_LAZY
 	moveq	pc, r8				@ go again
-	b	1b
+	ldr	r0, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
+	teq	r0, #0				@ if preempt lazy count != 0
+	beq	1b
+	mov	pc, r8				@ go again
+
 #endif
 
 __und_fault:
-- 
2.8.1

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

[PATCH RT 5/8] arm: lazy preempt: correct resched condition Steven Rostedt <rostedt@goodmis.org> - 2016-07-12 19:00 +0200

csiph-web