Bug 2502525 (CVE-2026-64163)

Summary: CVE-2026-64163 kernel: test_kprobes: clear kprobes between test runs
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's kprobes test module. Improper cleanup of kprobes and kretprobes (kernel probes used for debugging and tracing) between test runs can lead to registration failures. Repeated execution of the kprobes sanity tests can cause the kernel to crash, resulting in a denial of service. This vulnerability affects the stability of the kernel when running these specific diagnostic tests.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-07-19 17:04:18 UTC
In the Linux kernel, the following vulnerability has been resolved:

test_kprobes: clear kprobes between test runs

Running the kprobes sanity tests twice makes all tests fail and
eventually crashes the kernel.

[root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run
...
   # Totals: pass:5 fail:0 skip:0 total:5
   ok 1 kprobes_test
[root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run
...
  # test_kprobe: EXPECTATION FAILED at lib/tests/test_kprobes.c:64
  Expected 0 == register_kprobe(&kp), but
      register_kprobe(&kp) == -22 (0xffffffffffffffea)
...
  Unable to handle kernel paging request ...

The testsuite defines several kprobes and kretprobes as static variables
that are preserved across test runs.

After register_kprobe and unregister_kprobe, a kprobe contains some
leftover data that must be cleared before the kprobe can be registered
again. The tests are setting symbol_name to define the probe location.
Address and flags must be cleared.

The existing code clears some of the probes between subsequent tests, but
not between two test runs. The leftover data from a previous test run
makes the registrations fail in the next run.

Move the cleanups for all kprobes into kprobes_test_init, this function
is called before each single test (including the first test of a test
run).