This is a note to let you know that I've just added the patch titled

    clk: Check parent for NULL in clk_change_rate

to the 3.4-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     clk-check-parent-for-null-in-clk_change_rate.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From bf47b4fd8f9f81cd5ce40e1945c6334d088226d1 Mon Sep 17 00:00:00 2001
From: Pawel Moll <[email protected]>
Date: Fri, 8 Jun 2012 14:04:06 +0100
Subject: clk: Check parent for NULL in clk_change_rate

From: Pawel Moll <[email protected]>

commit bf47b4fd8f9f81cd5ce40e1945c6334d088226d1 upstream.

clk_change_rate() is accessing parent's rate without checking
if the parent exists at all. In case of root clocks this will
cause NULL pointer dereference.

This patch follows what clk_calc_new_rates() does in such
situation.

Signed-off-by: Pawel Moll <[email protected]>
Signed-off-by: Mike Turquette <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/clk/clk.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -834,18 +834,21 @@ static void clk_change_rate(struct clk *
 {
        struct clk *child;
        unsigned long old_rate;
+       unsigned long best_parent_rate = 0;
        struct hlist_node *tmp;
 
        old_rate = clk->rate;
 
+       if (clk->parent)
+               best_parent_rate = clk->parent->rate;
+
        if (clk->ops->set_rate)
                clk->ops->set_rate(clk->hw, clk->new_rate);
 
        if (clk->ops->recalc_rate)
-               clk->rate = clk->ops->recalc_rate(clk->hw,
-                               clk->parent->rate);
+               clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
        else
-               clk->rate = clk->parent->rate;
+               clk->rate = best_parent_rate;
 
        if (clk->notifier_count && old_rate != clk->rate)
                __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);


Patches currently in stable-queue which might be from [email protected] are

queue-3.4/clk-check-parent-for-null-in-clk_change_rate.patch
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