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authorTushar Behera <tushar.behera@linaro.org>2012-09-18 10:05:34 +0900
committerKukjin Kim <kgene.kim@samsung.com>2012-09-18 10:05:34 +0900
commitd6838a62b4d36d3e2791cffe155586973b20a381 (patch)
tree7eda3f38919335cd1e06873259ee2d1b21b30792 /arch
parentdbc5e1e89aafd484ad279ec6b9267dcd2c67df3f (diff)
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ARM: SAMSUNG: Use spin_lock_{irqsave,irqrestore} in clk_set_rate
The spinlock clocks_lock can be held during ISR, hence it is not safe to hold that lock with disabling interrupts. It fixes following potential deadlock. ========================================================= [ INFO: possible irq lock inversion dependency detected ] 3.6.0-rc4+ #2 Not tainted --------------------------------------------------------- swapper/0/1 just changed the state of lock: (&(&host->lock)->rlock){-.....}, at: [<c027fb0d>] sdhci_irq+0x15/0x564 but this lock took another, HARDIRQ-unsafe lock in the past: (clocks_lock){+.+...} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(clocks_lock); local_irq_disable(); lock(&(&host->lock)->rlock); lock(clocks_lock); <Interrupt> lock(&(&host->lock)->rlock); *** DEADLOCK *** Signed-off-by: Tushar Behera <tushar.behera@linaro.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/plat-samsung/clock.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm/plat-samsung/clock.c b/arch/arm/plat-samsung/clock.c
index 80eacca4682..d1116e2dfbe 100644
--- a/arch/arm/plat-samsung/clock.c
+++ b/arch/arm/plat-samsung/clock.c
@@ -144,6 +144,7 @@ long clk_round_rate(struct clk *clk, unsigned long rate)
int clk_set_rate(struct clk *clk, unsigned long rate)
{
+ unsigned long flags;
int ret;
if (IS_ERR(clk))
@@ -159,9 +160,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
if (clk->ops == NULL || clk->ops->set_rate == NULL)
return -EINVAL;
- spin_lock(&clocks_lock);
+ spin_lock_irqsave(&clocks_lock, flags);
ret = (clk->ops->set_rate)(clk, rate);
- spin_unlock(&clocks_lock);
+ spin_unlock_irqrestore(&clocks_lock, flags);
return ret;
}