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PM: sleep: wakeirq: harden dev_pm_clear_wake_irq() against races

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dev_pm_clear_wake_irq() currently uses a dangerous pattern where
dev->power.wakeirq is read and checked for NULL outside the lock.
If two callers invoke this function concurrently, both might see
a valid pointer and proceed. This could result in a double-free
when the second caller acquires the lock and tries to release the
same object.

Address this by removing the lockless check of dev->power.wakeirq.
Instead, acquire dev->power.lock immediately to ensure the check and
the subsequent operations are atomic. If dev->power.wakeirq is NULL
under the lock, simply unlock and return. This guarantees that
concurrent calls cannot race to free the same object.

Based on a quick scan of current users, I did not find an actual bug as
drivers seem to rely on their own synchronization. However, since
asynchronous usage patterns exist (e.g., in
drivers/net/wireless/ti/wlcore), I believe a race is theoretically
possible if the API is used less carefully in the future. This change
hardens the API to be robust against such cases.

Fixes: 4990d4fe32 ("PM / Wakeirq: Add automated device wake IRQ handling")
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Link: https://patch.msgid.link/20260203031943.1924-1-hanguidong02@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Gui-Dong Han 2026-02-03 11:19:43 +08:00 committed by Rafael J. Wysocki
parent 75ce02f4bc
commit 5c9ecd8e64
1 changed files with 7 additions and 4 deletions
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11
drivers/base/power/wakeirq.c
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@ -83,13 +83,16 @@ EXPORT_SYMBOL_GPL(dev_pm_set_wake_irq);
*/
void dev_pm_clear_wake_irq(struct device *dev)
{
struct wake_irq *wirq = dev->power.wakeirq;
struct wake_irq *wirq;
unsigned long flags;
if (!wirq)
return;
spin_lock_irqsave(&dev->power.lock, flags);
wirq = dev->power.wakeirq;
if (!wirq) {
spin_unlock_irqrestore(&dev->power.lock, flags);
return;
}
device_wakeup_detach_irq(dev);
dev->power.wakeirq = NULL;
spin_unlock_irqrestore(&dev->power.lock, flags);