fprobe: Release rethook after the ftrace_ops is unregistered

Summary

In the Linux kernel, the following vulnerability has been resolved: fprobe: Release rethook after the ftrace_ops is unregistered While running bpf selftests it's possible to get following fault: general protection fault, probably for non-canonical address \ 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI ... Call Trace: <TASK> fprobe_handler+0xc1/0x270 ? __pfx_bpf_testmod_init+0x10/0x10 ? __pfx_bpf_testmod_init+0x10/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_testmod_init+0x22/0x80 ? do_one_initcall+0x63/0x2e0 ? rcu_is_watching+0xd/0x40 ? kmalloc_trace+0xaf/0xc0 ? do_init_module+0x60/0x250 ? __do_sys_finit_module+0xac/0x120 ? do_syscall_64+0x37/0x90 ? entry_SYSCALL_64_after_hwframe+0x72/0xdc </TASK> In unregister_fprobe function we can't release fp->rethook while it's possible there are some of its users still running on another cpu. Moving rethook_free call after fp->ops is unregistered with unregister_ftrace_function call.

Timeline

1. Oct 4, 2025, 3:17 PM UTCCVE published
2. Oct 15, 2026, 9:35 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 15, 2026, 9:41 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 5b0ab78998e32564a011b14c4c7f9c81e2d42b9d · fixed in ce3ec57faff559ccae1e0150c1f077eb2df648a4; From 5b0ab78998e32564a011b14c4c7f9c81e2d42b9d · fixed in 03d63255a5783243c110aec5e6ae2f1475c3be76; From 5b0ab78998e32564a011b14c4c7f9c81e2d42b9d · fixed in 5f81018753dfd4989e33ece1f0cb6b8aae498b82

• Linux Linux

  5.18

• KernelLinux

  From 5.18.0 · fixed in 6.1.40; From 6.2.0 · fixed in 6.4.5

References 3