Thread (64 messages) flat view 64 messages, 4 authors, 2016-06-03

[PATCH 01/16] clk: fix critical clock locking

From: Maxime Ripard <hidden>
Date: 2016-05-13 07:50:00
Also in: linux-clk

Hi Stephen,

On Mon, May 09, 2016 at 03:11:46PM -0700, Stephen Boyd wrote:
On 05/08, Maxime Ripard wrote:
quoted
The critical clock handling in __clk_core_init isn't taking the enable lock
before calling clk_core_enable, which in turns triggers the warning in the
lockdep_assert_held call in that function when lockep is enabled.

Add the calls to clk_enable_lock/unlock to make sure it doesn't happen.

Fixes: 32b9b1096186 ("clk: Allow clocks to be marked as CRITICAL")
Signed-off-by: Maxime Ripard <redacted>
---
Why is this patch hiding in this series?
Sorry, I discovered it while working on this, and somehow it slipped
in there. I'll resend it separately.
quoted
 drivers/clk/clk.c | 7 +++++++
 1 file changed, 7 insertions(+)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index ce39add5a258..16a38df3c688 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2404,8 +2404,15 @@ static int __clk_core_init(struct clk_core *core)
 		core->ops->init(core->hw);
 
 	if (core->flags & CLK_IS_CRITICAL) {
+		unsigned long flags;
+
+		clk_prepare_lock();
 		clk_core_prepare(core);
+		clk_prepare_unlock();
It looks like we already hold the prepare lock at this point.
You're right. I thought I removed it, but obviously I didn't.

I'll send a v2.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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