CVE-2026-53278arm_mpam: Check whether the config array is allocated before destroying it

Official description

In the Linux kernel, the following vulnerability has been resolved: arm_mpam: Check whether the config array is allocated before destroying it __destroy_component_cfg() is called to free the configuration array. It uses the embedded 'garbage' structure, which means the array has to be allocated. If __destroy_component_cfg() is called from mpam_disable() before the configuration was ever allocated, then a NULL pointer is dereferenced. Check for this case and return early if the configuration is not allocated. __destroy_component_cfg() also frees the mbwu_state as this is allocated by __allocate_component_cfg(). As the mbwu_state is allocated after comp->cfg is set, and is also under mpam_list_lock, only the first pointer needs checking.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/8eb6dc76eeae5302c0d885906a0e469ef9630a59
• https://git.kernel.org/stable/c/6ccbb613b42a1f1ba7bfd547a148f644a902a25c