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authorMatthias Brugger <matthias.bgg@gmail.com>2015-02-19 13:41:33 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2015-02-25 12:28:49 +0300
commitd4a19eb3b15a4ba98f627182f48d5bc0cffae670 (patch)
treeba55b0edb3f786383a00f7700906ea455e141075 /drivers/clocksource
parenta8b1b9fc927400045fb7631d5b12093aaf5d939d (diff)
downloadlinux-d4a19eb3b15a4ba98f627182f48d5bc0cffae670.tar.xz
clocksource: mtk: Fix race conditions in probe code
We have two race conditions in the probe code which could lead to a null pointer dereference in the interrupt handler. The interrupt handler accesses the clockevent device, which may not yet be registered. First race condition happens when the interrupt handler gets registered before the interrupts get disabled. The second race condition happens when the interrupts get enabled, but the clockevent device is not yet registered. Fix that by disabling the interrupts before we register the interrupt and enable the interrupts after the clockevent device got registered. Reported-by: Gongbae Park <yongbae2@gmail.com> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/mtk_timer.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
index 32a3d25795d3..68ab42356d0e 100644
--- a/drivers/clocksource/mtk_timer.c
+++ b/drivers/clocksource/mtk_timer.c
@@ -224,6 +224,8 @@ static void __init mtk_timer_init(struct device_node *node)
}
rate = clk_get_rate(clk);
+ mtk_timer_global_reset(evt);
+
if (request_irq(evt->dev.irq, mtk_timer_interrupt,
IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
pr_warn("failed to setup irq %d\n", evt->dev.irq);
@@ -232,8 +234,6 @@ static void __init mtk_timer_init(struct device_node *node)
evt->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
- mtk_timer_global_reset(evt);
-
/* Configure clock source */
mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN);
clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC),
@@ -241,10 +241,11 @@ static void __init mtk_timer_init(struct device_node *node)
/* Configure clock event */
mtk_timer_setup(evt, GPT_CLK_EVT, TIMER_CTRL_OP_REPEAT);
- mtk_timer_enable_irq(evt, GPT_CLK_EVT);
-
clockevents_config_and_register(&evt->dev, rate, 0x3,
0xffffffff);
+
+ mtk_timer_enable_irq(evt, GPT_CLK_EVT);
+
return;
err_clk_disable: