linux-kernel - [PATCH AUTOSEL 6.12 05/26] power: supply: collie: Fix wakeup source leaks on device unbind

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Message-Id: <20250530124012.2575409-5-sashal@kernel.org>
Date: Fri, 30 May 2025 08:39:51 -0400
From: Sasha Levin <sashal@...nel.org>
To: patches@...ts.linux.dev,
	stable@...r.kernel.org
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Sebastian Reichel <sebastian.reichel@...labora.com>,
	Sasha Levin <sashal@...nel.org>,
	sre@...nel.org,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH AUTOSEL 6.12 05/26] power: supply: collie: Fix wakeup source leaks on device unbind

From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

[ Upstream commit c73d19f89cb03c43abbbfa3b9caa1b8fc719764c ]

Device can be unbound, so driver must also release memory for the wakeup
source.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Link: https://lore.kernel.org/r/20250406202730.55096-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---

Perfect! This confirms the pattern. Now let me analyze the commit:
**YES** This commit should be backported to stable kernel trees. Here's
my extensive analysis: ## Justification for Backporting ### 1. **Bug Fix
Nature** The commit fixes a resource leak bug where wakeup sources are
not properly cleaned up when the device is unbound. This is a clear bug
fix that affects system resource management. ### 2. **Matching Pattern
with Similar Commits** This commit follows the exact same pattern as the
similar commits marked "YES" for backporting: - **Similar Commit #1
(gpio: mpc8xxx)** and **Similar Commit #3 (gpio: zynq)** both have
identical commit messages and fix the same type of wakeup source leak by
adding `device_init_wakeup(&pdev->dev, 0)` in the remove function. - All
these commits are from the same author (Krzysztof Kozlowski) and have
`Cc: stable@...r.kernel.org` in their commit messages, indicating
explicit intention for stable tree inclusion. ### 3. **Code Analysis**
The code change is minimal and surgical: - **Single line addition**:
`device_init_wakeup(&ucb->dev, 0);` in the `collie_bat_remove()`
function - **Proper cleanup ordering**: The line is added at the
beginning of the remove function, which is the correct place for
resource cleanup - **Symmetric operation**: The probe function calls
`device_init_wakeup(&ucb->dev, 1)` at line 414, and now the remove
function properly disables it with `device_init_wakeup(&ucb->dev, 0)`
### 4. **Resource Leak Prevention** From examining the kernel tree, I
can see that: - The probe function enables wakeup with
`device_init_wakeup(&ucb->dev, 1)` - Without this fix, when the driver
is unbound, the wakeup source memory is leaked - This follows the
established pattern seen in other drivers like gpio-zynq.c where
`device_init_wakeup(&pdev->dev, 0)` is called in remove functions ### 5.
**Low Risk Assessment** - **Minimal scope**: Only affects the collie
battery driver cleanup path - **No functional changes**: Doesn't change
driver behavior, only fixes resource cleanup - **No architectural
changes**: Single line addition for proper resource management - **No
new features**: Pure bug fix ### 6. **Stable Tree Criteria Compliance**
- ✅ **Important bug fix**: Prevents resource leaks - ✅ **Minimal risk**:
Single line, well-understood API call - ✅ **No new features**: Only
fixes cleanup - ✅ **Small and contained**: Confined to one driver's
remove function - ✅ **Clear side effects**: Only positive effect of
proper resource cleanup ### 7. **Explicit Stable Tree Intent** The
commit message doesn't include `Cc: stable@...r.kernel.org`, but the
similar commits #1 and #3 from the same author fixing identical issues
do have this tag, suggesting this is part of a series addressing wakeup
source leaks across multiple drivers. The fix is essential for proper
resource management and follows established kernel patterns for wakeup
source cleanup during device unbinding.

 drivers/power/supply/collie_battery.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/power/supply/collie_battery.c b/drivers/power/supply/collie_battery.c
index 68390bd1004f0..3daf7befc0bf6 100644
--- a/drivers/power/supply/collie_battery.c
+++ b/drivers/power/supply/collie_battery.c
@@ -440,6 +440,7 @@ static int collie_bat_probe(struct ucb1x00_dev *dev)
 
 static void collie_bat_remove(struct ucb1x00_dev *dev)
 {
+	device_init_wakeup(&ucb->dev, 0);
 	free_irq(gpiod_to_irq(collie_bat_main.gpio_full), &collie_bat_main);
 	power_supply_unregister(collie_bat_bu.psy);
 	power_supply_unregister(collie_bat_main.psy);
-- 
2.39.5