[RFC 0/1] KVM: selftests: rseq_test: use vdso_getcpu() instead of syscall()

Robert Hoo
2022-11-02T02:01:48Z

Recently, our QA often meet the test assert failure in KVM selftest rseq_test.
e.g.
==== Test Assertion Failure ====
rseq_test.c:273: i > (NR_TASK_MIGRATIONS / 2)
pid=391366 tid=391366 errno=4 - Interrupted system call
1 0x00000000004027dd: main at rseq_test.c:272
2 0x00007f7fc383ad84: ?? ??:0
3 0x000000000040286d: _start at ??:?
Only performed 32083 KVM_RUNs, task stalled too much?

Though this is not a bug [1], passing this assert means the race condition
can be more hit, which is the original purpose of this test case design.

[1] https://lore.kernel.org/kvm/YvwYxeE4vc%2FSrbil@google.com/

Robert Hoo (1):
KVM: selftests: rseq_test: use vdso_getcpu() instead of syscall()

tools/testing/selftests/kvm/rseq_test.c | 32 ++++++++++++++++++-------
1 file changed, 24 insertions(+), 8 deletions(-)

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2.31.1