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.]
Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:NI:NA:H5.5/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H