CVE-2025-21645 platform/x86/amd/pmc: Only disable IRQ1 wakeup where i8042 actually enabled it
A logic error in the AMD PMC driver causes an unbalanced IRQ wake disable warning during hibernation, potentially leading to system instability or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-21645?
CVE-2025-21645 is a medium-severity denial of service vulnerability in Linux kernel, published on 19 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
platform/x86/amd/pmc: Only disable IRQ1 wakeup where i8042 actually enabled it
Wakeup for IRQ1 should be disabled only in cases where i8042 had actually enabled it, otherwise "wake_depth" for this IRQ will try to drop below zero and there will be an unpleasant WARN() logged:
kernel: atkbd serio0: Disabling IRQ1 wakeup source to avoid platform firmware bug kernel: ------------[ cut here ]------------ kernel: Unbalanced IRQ 1 wake disable kernel: WARNING: CPU: 10 PID: 6431 at kernel/irq/manage.c:920 irq_set_irq_wake+0x147/0x1a0
The PMC driver uses DEFINE_SIMPLE_DEV_PM_OPS() to define its dev_pm_ops which sets amd_pmc_suspend_handler() to the .suspend, .freeze, and .poweroff handlers. i8042_pm_suspend(), however, is only set as the .suspend handler.
Fix the issue by call PMC suspend handler only from the same set of dev_pm_ops handlers as i8042_pm_suspend(), which currently means just the .suspend handler.
To reproduce this issue try hibernating (S4) the machine after a fresh boot without putting it into s2idle first.
[ij: edited the commit message.]
Which versions are affected by CVE-2025-21645?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21645?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-21645 being exploited?
There is no known exploitation of CVE-2025-21645 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21645, DEBIAN-CVE-2025-21645, GHSA-2phg-f479-57pq, ROOT-OS-DEBIAN-12-CVE-2025-21645, UBUNTU-CVE-2025-21645.