drm/amd/display: Fix ISM dc_lock deadlock during suspend
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No sign of exploitation. No public exploitation artifact known so far.
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exploitation probability
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observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix ISM dc_lock deadlock during suspend
[Why]
System hang observed during suspend/resume while video is playing.
amdgpu_dm_ism_disable() is called under dc_lock and waits for ISM
delayed work via disable_delayed_work_sync(). The work handlers
themselves take dc_lock, producing an ABBA deadlock when a worker is
in flight at suspend time.
[How]
Split the disable path into two phases with opposite locking
contracts:
1. amdgpu_dm_ism_disable() -- quiesces workers, must NOT hold
dc_lock.
2. amdgpu_dm_ism_force_full_power() (new) -- drives the ISM FSM
back to FULL_POWER_RUNNING, must hold dc_lock.
Affected products
Linux · Linux