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.
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Oct 6, 2025 | Oct 6, 2025 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Oct 4, 2025 |
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