CVE-2026-98587

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

firewire: cdev: fix back-transition for iso_resource_auto client resource

The todo member of iso_resource_auto structure represents the state of the client resource and normally transitions in the following order:

ISO_RES_AUTO_ALLOC -> ISO_RES_AUTO_REALLOC -> ISO_RES_AUTO_DEALLOC

However, concurrent access from the work item and the file descriptor release function can cause the state to transition backwards from ISO_RES_AUTO_DEALLOC to ISO_RES_AUTO_REALLOC.

Prevent the back-transition by checking the current state before updating it in the work item.