selftests/bpf: Test RCU pointer invalidation after spin unlock

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The verifier previously accepted a task kptr after the final spin unlock
ended its RCU protection in a sleepable program. The pointer could then be
used after the task was freed.

Add a negative test for that case. Add positive controls showing that the
pointer remains valid in a non-sleepable program and while an explicit RCU
read-side section is still active.

Assisted-by: Codex:gpt-5.6-sol
Assisted-by: ChatGPT:GPT-5.6-Pro
Signed-off-by: Ning Ding <dingning04@gmail.com>
Link: https://lore.kernel.org/bpf/20260803112615.3362122-3-dingning04@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

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Ning Ding 2026-08-03 04:26:09 -07:00 • committed by Kumar Kartikeya Dwivedi

parent 180c700071

commit bb2df6fd89

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2

tools/testing/selftests/bpf/prog_tests/task_kfunc.c

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12

tools/testing/selftests/bpf/progs/task_kfunc_common.h

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tools/testing/selftests/bpf/progs/task_kfunc_failure.c

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tools/testing/selftests/bpf/progs/task_kfunc_success.c

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