diff options
author | Tushar Behera <tushar.behera@linaro.org> | 2012-09-07 11:31:05 +0530 |
---|---|---|
committer | Tushar Behera <tushar.behera@linaro.org> | 2012-09-07 11:31:05 +0530 |
commit | fb28eb40d34a2a084f3c2d9d6fbae1accf237f7f (patch) | |
tree | af8649af0a3911bc202fa65300831e92446ac0f7 | |
parent | 6d82c3687a61b83784f5fa6cb3e62b30a3de3fe3 (diff) |
ARM: SAMSUNG: Use spin_lock_{irqsave,irqrestore} in clk_set_ratesamsung-lt-v3.6-rc4
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>
-rw-r--r-- | arch/arm/plat-samsung/clock.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm/plat-samsung/clock.c b/arch/arm/plat-samsung/clock.c index 8b086f6139b..3803dc9e07f 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; } |