From: Tero Kristo <t-kristo@xxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 067bb1741c27c8d3b74ac98c0b8fc12b31e67005 upstream. In some cases, clocks can switch their parent with clk_set_rate, for example clk_mux can do this in some cases. Current implementation of clk_change_rate uses un-safe list iteration on the clock children, which will cause wrong clocks to be parsed in case any of the clock children change their parents during the change rate operation. Fixed by using the safe list iterator instead. The problem was detected due to some divide by zero errors generated by clock init on dra7-evm board, see discussion under http://article.gmane.org/gmane.linux.ports.arm.kernel/349180 for details. Fixes: 71472c0c06cf ("clk: add support for clock reparent on set_rate") Signed-off-by: Tero Kristo <t-kristo@xxxxxx> Reported-by: Nishanth Menon <nm@xxxxxx> Signed-off-by: Mike Turquette <mturquette@xxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- drivers/clk/clk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index a004769528e6..f5966413fbb2 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1368,6 +1368,7 @@ static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long even static void clk_change_rate(struct clk *clk) { struct clk *child; + struct hlist_node *tmp; unsigned long old_rate; unsigned long best_parent_rate = 0; @@ -1391,7 +1392,11 @@ static void clk_change_rate(struct clk *clk) if (clk->notifier_count && old_rate != clk->rate) __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); - hlist_for_each_entry(child, &clk->children, child_node) { + /* + * Use safe iteration, as change_rate can actually swap parents + * for certain clock types. + */ + hlist_for_each_entry_safe(child, tmp, &clk->children, child_node) { /* Skip children who will be reparented to another clock */ if (child->new_parent && child->new_parent != clk) continue; -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html