Commit 1eaa188f authored Nov 15, 2023 by Maria Yu Committed by Greg Kroah-Hartman Dec 08, 2023

pinctrl: avoid reload of p state in list iteration



commit 4198a9b571065978632276264e01d71d68000ac5 upstream.

When in the list_for_each_entry iteration, reload of p->state->settings
with a local setting from old_state will turn the list iteration into an
infinite loop.

The typical symptom when the issue happens, will be a printk message like:

  "not freeing pin xx (xxx) as part of deactivating group xxx - it is
already used for some other setting".

This is a compiler-dependent problem, one instance occurred using Clang
version 10.0 on the arm64 architecture with linux version 4.19.

Fixes: 6e5e959d ("pinctrl: API changes to support multiple states per device")
Signed-off-by: Maria Yu <quic_aiquny@quicinc.com>
Cc:  <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20231115102824.23727-1-quic_aiquny@quicinc.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 40532b29

drivers/pinctrl/core.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -1237,17 +1237,17 @@ static void pinctrl_link_add(struct pinctrl_dev *pctldev,
		static int pinctrl_commit_state(struct pinctrl p, struct pinctrl_state state)
		{
		struct pinctrl_setting setting, setting2;
		struct pinctrl_state *old_state = p->state;
		struct pinctrl_state *old_state = READ_ONCE(p->state);
		int ret;

		if (p->state) {
		if (old_state) {
		/*
		* For each pinmux setting in the old state, forget SW's record
		* of mux owner for that pingroup. Any pingroups which are
		* still owned by the new state will be re-acquired by the call
		* to pinmux_enable_setting() in the loop below.
		*/
		list_for_each_entry(setting, &p->state->settings, node) {
		list_for_each_entry(setting, &old_state->settings, node) {
		if (setting->type != PIN_MAP_TYPE_MUX_GROUP)
		continue;
		pinmux_disable_setting(setting);