Deadlock Affecting kernel-rt package, versions *

Note: Versions mentioned in the description apply only to the upstream kernel-rt package and not the kernel-rt package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

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.

• https://access.redhat.com/security/cve/CVE-2023-52498
• https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
• https://git.kernel.org/stable/c/7839d0078e0d5e6cc2fa0b0dfbee71de74f1e557
• https://git.kernel.org/stable/c/9bd3dce27b01c51295b60e1433e1dadfb16649f7
• https://git.kernel.org/stable/c/a1d62c775b07213c73f81ae842424c74dd14b5f0
• https://git.kernel.org/stable/c/e1c9d32c98309ae764893a481552d3f99d46cb34
• https://git.kernel.org/stable/c/e681e29d1f59a04ef773296e4bebb17b1b79f8fe
• https://git.kernel.org/stable/c/f46eb832389f162ad13cb780d0b8cde93641990d