Question: What is CVE-2025-21645?
Answer: CVE-2025-21645 is a vulnerability classified as nan with a CVSS score of nan. It falls under nan and affects the system as follows: 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.]