clk: Really fix deadlock with mmap_sem

bebarino · Michael Turquette · commit 89f7e9de59bf · 2014-12-15T17:02:06.000-08:00
Commit 6314b67 (clk: Don't hold prepare_lock across debugfs creation, 2014-09-04) forgot to update one place where we hold the prepare_lock while creating debugfs directories. This means we still have the chance of a deadlock that the commit was trying to fix. Actually fix it by moving the debugfs creation outside the prepare_lock. Cc: <stable@vger.kernel.org> # 3.18 Reported-by: Russell King <rmk+kernel@arm.linux.org.uk> Fixes: 6314b67 "clk: Don't hold prepare_lock across debugfs creation" Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Michael Turquette <mturquette@linaro.org> [mturquette@linaro.org: removed lockdep_assert]
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
@@ -240,7 +240,6 @@ static const struct file_operations clk_dump_fops = {
 	.release	= single_release,
 };
 
-/* caller must hold prepare_lock */
 static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
 {
 	struct dentry *d;
@@ -1944,7 +1943,6 @@ int __clk_init(struct device *dev, struct clk *clk)
 	else
 		clk->rate = 0;
 
-	clk_debug_register(clk);
 	/*
 	 * walk the list of orphan clocks and reparent any that are children of
 	 * this clock
@@ -1979,6 +1977,9 @@ int __clk_init(struct device *dev, struct clk *clk)
 out:
 	clk_prepare_unlock();
 
+	if (!ret)
+		clk_debug_register(clk);
+
 	return ret;
 }
 
