CVE-2026-31567

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

PM: sleep: Drop spurious WARN_ON() from pm_restore_gfp_mask()

Commit 35e4a69b2003f (PM: sleep: Allow pm_restrict_gfp_mask() stacking) introduced refcount-based GFP mask management that warns when pm_restore_gfp_mask() is called with saved_gfp_count == 0.

Some hibernation paths call pm_restore_gfp_mask() defensively where the GFP mask may or may not be restricted depending on the execution path. For example, the uswsusp interface invokes it in SNAPSHOT_CREATE_IMAGE, SNAPSHOT_UNFREEZE, and snapshot_release(). Before the stacking change this was a silent no-op; it now triggers a spurious WARNING.

Remove the WARN_ON() wrapper from the !saved_gfp_count check while retaining the check itself, so that defensive calls remain harmless without producing false warnings.

[ rjw: Subject tweak ]

Weakness

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

Affected Software

Extended Description

While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.

Potential Mitigations

References

• https://git.kernel.org/stable/c/3025ca5daa9d682b629c0c958b538e41deeb559d
• https://git.kernel.org/stable/c/a8d51efb5929ae308895455a3e496b5eca2cd143
• https://git.kernel.org/stable/c/f19d1323aa3dd7ead469aef47d9085f8939565d9