From e47c6a3408ea6bcfc5204f23d5a5b209de6e68b9 Mon Sep 17 00:00:00 2001
From: Fengguang Wu <fengguang.wu@intel.com>
Date: Mon, 30 Jul 2012 14:39:54 -0700
Subject: [PATCH] clk: validate pointer in __clk_disable()
clk_get() returns -ENOENT on error and some careless caller might
dereference it without error checking:
In mxc_rnga_remove():
struct clk *clk = clk_get(&pdev->dev, "rng");
// ...
clk_disable(clk);
Since it's insane to audit the lots of existing and future clk users,
let's add a check in the callee to avoid kernel panic and warn about
any buggy user.
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Viresh Kumar <viresh.kumar@st.com>
Cc: viresh kumar <viresh.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/clk/clk.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index c87fdd7105609..efdfd009c2701 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -465,6 +465,9 @@ static void __clk_disable(struct clk *clk)
if (!clk)
return;
+ if (WARN_ON(IS_ERR(clk)))
+ return;
+
if (WARN_ON(clk->enable_count == 0))
return;
--
2.30.2