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 irqsetirq_wake+0x147/0x1a0
The PMC driver uses DEFINESIMPLEDEVPMOPS() to define its devpmops which sets amdpmcsuspendhandler() to the .suspend, .freeze, and .poweroff handlers. i8042pm_suspend(), however, is only set as the .suspend handler.
Fix the issue by call PMC suspend handler only from the same set of devpmops handlers as i8042pmsuspend(), 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.]