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authorJoonyoung Shim <jy0922.shim@samsung.com>2017-01-17 13:54:36 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-26 08:23:48 +0100
commit098b62b757a4303f576a6d2bb8f11d0ad93797d1 (patch)
tree1fbc7a586d6490b3ed4edaf2f8953440ccc7bba7 /drivers
parenta07563c3cf05ead6e08c50513a386261c93b8f33 (diff)
clocksource/exynos_mct: Clear interrupt when cpu is shut down
commit bc7c36eedb0c7004aa06c2afc3c5385adada8fa3 upstream. 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: 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/clocksource/exynos_mct.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index ff44082a0827..47f8aafe3344 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -482,6 +482,7 @@ static void exynos4_local_timer_stop(struct mct_clock_event_device *mevt)
if (mct_int_type == MCT_INT_SPI) {
if (evt->irq != -1)
disable_irq_nosync(evt->irq);
+ exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
} else {
disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
}