From d6838a62b4d36d3e2791cffe155586973b20a381 Mon Sep 17 00:00:00 2001 From: Tushar Behera Date: Tue, 18 Sep 2012 10:05:34 +0900 Subject: [PATCH] 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: [] 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); lock(&(&host->lock)->rlock); *** DEADLOCK *** Signed-off-by: Tushar Behera Signed-off-by: Kukjin Kim --- arch/arm/plat-samsung/clock.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm/plat-samsung/clock.c b/arch/arm/plat-samsung/clock.c index 80eacca4682a..d1116e2dfbea 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; } -- 2.39.2