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pinctrl: avoid reload of p state in list iteration

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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: 6e5e959dde ("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>
This commit is contained in:
Maria Yu 2023-11-15 18:28:24 +08:00 committed by Linus Walleij
parent df572eba4e
commit 4198a9b571
1 changed files with 3 additions and 3 deletions
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6
drivers/pinctrl/core.c
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@ -1262,17 +1262,17 @@ 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);