clocksource/exynos_mct: Clear interrupt when cpu is shut down
authorJoonyoung Shim <jy0922.shim@samsung.com>
Tue, 17 Jan 2017 04:54:36 +0000 (13:54 +0900)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 17 Jan 2017 09:08:38 +0000 (10:08 +0100)
commitbc7c36eedb0c7004aa06c2afc3c5385adada8fa3
tree14ce1ae3cce8013aa4bc46297f6370ec0527be78
parent49def1853334396f948dcb4cedb9347abb318df5
clocksource/exynos_mct: Clear interrupt when cpu is shut down

When a CPU goes offline a potentially pending timer interrupt is not
cleared. When the CPU comes online again then the pending interrupt is
delivered before the per cpu clockevent device is initialized. As a
consequence the tick interrupt handler dereferences a NULL pointer.

[   51.251378] Unable to handle kernel NULL pointer dereference at virtual address 00000040
[   51.289348] task: ee942d00 task.stack: ee960000
[   51.293861] PC is at tick_periodic+0x38/0xb0
[   51.298102] LR is at tick_handle_periodic+0x1c/0x90

Clear the pending interrupt in the cpu dying path.

Fixes: 56a94f13919c ("clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier")
Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: linux-samsung-soc@vger.kernel.org
Cc: cw00.choi@samsung.com
Cc: daniel.lezcano@linaro.org
Cc: stable@vger.kernel.org
Cc: javier@osg.samsung.com
Cc: kgene@kernel.org
Cc: krzk@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1484628876-22065-1-git-send-email-jy0922.shim@samsung.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
drivers/clocksource/exynos_mct.c