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

Steven Rostedt
2016-07-12T16:58:16Z

[-- Attachment #1: 0005-arm-lazy-preempt-correct-resched-condition.patch --]
[-- Type: text/plain, Size: 1193 bytes --]

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