In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure
When bpf_trampoline_update() fails before modify_fentry_multi()/
unregister_fentry_multi() is called, cur_image is unchanged
(cur_image == old_image) and ftrace still calls into it. Freeing
old_image in that case causes a UAF.
Only free old_image when it differs from cur_image.
