| From d9c6067e9a297172b790f4527b16f76b329f303a Mon Sep 17 00:00:00 2001 |
| From: Joonyoung Shim <jy0922.shim@samsung.com> |
| Date: Tue, 17 Jan 2017 13:54:36 +0900 |
| Subject: [PATCH] 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: 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> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c |
| index 41840d02c331..3845c9ab7e39 100644 |
| --- a/drivers/clocksource/exynos_mct.c |
| +++ b/drivers/clocksource/exynos_mct.c |
| @@ -491,6 +491,7 @@ static int exynos4_mct_dying_cpu(unsigned int cpu) |
| 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]); |
| } |
| -- |
| 2.10.1 |
| |