CVE-2026-89749

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

tracing: Fix crash passing ERR_PTR to kthread_stop()

event_test_stuff() calls kthread_run() and unconditionally passes the
returned task_struct pointer to kthread_stop(). kthread_run() returns an
error pointer such as ERR_PTR(-ENOMEM) when kthread creation fails, for
example under memory pressure during the boot-time event self-test.
kthread_stop() then dereferences the invalid pointer, crashing the kernel.

Check the result of kthread_run() before passing it to kthread_stop(). Use
WARN_ON() so that a failure to create the self-test thread does not go
unnoticed, matching the ring-buffer self-test fix in commit
91542863abad ("ring-buffer: Fix crash passing ERR_PTR to kthread_stop()").