CVE-2026-64163: test_kprobes: clear kprobes between test runs

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

testkprobes: 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/kprobestest/run ... # Totals: pass:5 fail:0 skip:0 total:5 ok 1 kprobestest [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobestest/run ... # testkprobe: EXPECTATION FAILED at lib/tests/testkprobes.c:64 Expected 0 == registerkprobe(&kp), but registerkprobe(&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 registerkprobe and unregisterkprobe, a kprobe contains some leftover data that must be cleared before the kprobe can be registered again. The tests are setting symbolname 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 kprobestestinit, this function is called before each single test (including the first test of a test run).