🛡️ CVE-2023-52498 — kernel

PM: sleep: Fix possible deadlocks in core system-wide PM code

In the Linux kernel, the following vulnerability has been resolved:

PM: sleep: Fix possible deadlocks in core system-wide PM code

It is reported that in low-memory situations the system-wide resume core

code deadlocks, because async_schedule_dev() executes its argument

function synchronously if it cannot allocate memory (and not only in

that case) and that function attempts to acquire a mutex that is already

held. Executing the argument function synchronously from within

dpm_async_fn() may also be problematic for ordering reasons (it may

cause a consumer device's resume callback to be invoked before a

requisite supplier device's one, for example).

Address this by changing the code in question to use

async_schedule_dev_nocall() for scheduling the asynchronous

execution of device suspend and resume functions and to directly

run them synchronously if async_schedule_dev_nocall() returns false.