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@xxxxxxxxxx>
---
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 65c5eca..9b71719 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;
}
--
1.7.4.1
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