Commit-ID: d4a19eb3b15a4ba98f627182f48d5bc0cffae670
Gitweb: http://git.kernel.org/tip/d4a19eb3b15a4ba98f627182f48d5bc0cffae670
Author: Matthias Brugger <matthias.bgg@xxxxxxxxx>
AuthorDate: Thu, 19 Feb 2015 11:41:33 +0100
Committer: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
CommitDate: Wed, 25 Feb 2015 10:28:49 +0100
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@xxxxxxxxx>
Signed-off-by: Matthias Brugger <matthias.bgg@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
---
drivers/clocksource/mtk_timer.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
index 32a3d25..68ab423 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:
--
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