[PATCH AUTOSEL 6.19-6.12] power: sequencing: fix missing state_lock in pwrseq_power_on() error path

[PATCH AUTOSEL 6.19-6.12] power: sequencing: fix missing state_lock in pwrseq_power_on() error path

[Sasha Levin]

From: Ziyi Guo <n7l8m4@u.northwestern.edu>

[ Upstream commit e1dccb485c2876ac1318f36ccc0155416c633a48 ]

pwrseq_power_on() calls pwrseq_unit_disable() when the
post_enable callback fails. However, this call is outside the
scoped_guard(mutex, &pwrseq->state_lock) block that ends.

pwrseq_unit_disable() has lockdep_assert_held(&pwrseq->state_lock),
which will fail when called from this error path.

Add the scoped_guard block to cover the post_enable callback and its
error handling to ensure the lock is held when pwrseq_unit_disable() is
called.

Signed-off-by: Ziyi Guo <n7l8m4@u.northwestern.edu>
Link: https://patch.msgid.link/20260130182651.1576579-1-n7l8m4@u.northwestern.edu
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

The power sequencing core was introduced in v6.11. So this fix is
relevant for stable trees v6.11.y and later (6.12.y, 6.13.y, etc.).

### 8. SELF-CONTAINEDNESS

This is a completely self-contained fix. It doesn't depend on any other
patches. It simply wraps two existing lines of code with the appropriate
lock scope.

### VERDICT

**Meets stable criteria:**
- **Obviously correct**: Yes — the lock is required (enforced by
  `lockdep_assert_held`), and it was missing.
- **Fixes a real bug**: Yes — lockdep assertion failure and potential
  race condition.
- **Small and contained**: Yes — 6 lines changed in 1 file.
- **No new features**: Correct — purely a locking fix.
- **Low regression risk**: Adding a lock that was already required by
  the callee.

The fix is small, surgical, obviously correct, and fixes a real locking
bug that would trigger lockdep warnings and could lead to race
conditions. It meets all stable kernel criteria.

**YES**

 drivers/power/sequencing/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/power/sequencing/core.c b/drivers/power/sequencing/core.c
index 190564e559885..1fcf0af7cc0bb 100644
--- a/drivers/power/sequencing/core.c
+++ b/drivers/power/sequencing/core.c
@@ -914,8 +914,10 @@ int pwrseq_power_on(struct pwrseq_desc *desc)
 	if (target->post_enable) {
 		ret = target->post_enable(pwrseq);
 		if (ret) {
-			pwrseq_unit_disable(pwrseq, unit);
-			desc->powered_on = false;
+			scoped_guard(mutex, &pwrseq->state_lock) {
+				pwrseq_unit_disable(pwrseq, unit);
+				desc->powered_on = false;
+			}
 		}
 	}
 
-- 
2.51.0