diff options
| author | Gui-Dong Han <hanguidong02@gmail.com> | 2026-02-03 11:19:43 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2026-02-03 22:22:37 +0100 |
| commit | 5c9ecd8e6437cd55a38ea4f1e1d19cee8e226cb8 (patch) | |
| tree | b8fcbe32593b687f8d58f8b5ff7ea0c0811a7490 | |
| parent | 75ce02f4bc9a8b8350b6b1b01872467b0cc960cc (diff) | |
PM: sleep: wakeirq: harden dev_pm_clear_wake_irq() against races
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: 4990d4fe327b ("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>
| -rw-r--r-- | drivers/base/power/wakeirq.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c index 8aa28c08b289..c0809d18fc54 100644 --- a/drivers/base/power/wakeirq.c +++ b/drivers/base/power/wakeirq.c @@ -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) + spin_lock_irqsave(&dev->power.lock, flags); + wirq = dev->power.wakeirq; + if (!wirq) { + spin_unlock_irqrestore(&dev->power.lock, flags); return; + } - spin_lock_irqsave(&dev->power.lock, flags); device_wakeup_detach_irq(dev); dev->power.wakeirq = NULL; spin_unlock_irqrestore(&dev->power.lock, flags); |