diff options
author | Tushar Behera <tushar.behera@linaro.org> | 2012-09-18 01:05:34 (GMT) |
---|---|---|
committer | Kukjin Kim <kgene.kim@samsung.com> | 2012-09-18 01:05:34 (GMT) |
commit | d6838a62b4d36d3e2791cffe155586973b20a381 (patch) | |
tree | 7eda3f38919335cd1e06873259ee2d1b21b30792 | |
parent | dbc5e1e89aafd484ad279ec6b9267dcd2c67df3f (diff) | |
download | linux-fsl-qoriq-d6838a62b4d36d3e2791cffe155586973b20a381.tar.xz |
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>
-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 80eacca..d1116e2 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; } |