915b7f6f9a
This test triggers a TM Bad Thing by raising a signal in transactional state and forcing a pagefault to happen in kernelspace when the kernel signal handling code first touches the user signal stack. This is inspired by the test tm-signal-context-force-tm but uses userfaultfd to make the test deterministic. While this test always triggers the bug in one run, I had to execute tm-signal-context-force-tm several times (the test runs 5000 times each execution) to trigger the same bug. tm-signal-context-force-tm is kept instead of replaced because, while this test is more reliable and triggers the same bug, tm-signal-context-force-tm has a better coverage, in the sense that by running the test several times it might trigger the pagefault and/or be preempted at different places. v3: skip test if userfaultfd is unavailable. Signed-off-by: Gustavo Luiz Duarte <gustavold@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200211033831.11165-2-gustavold@linux.ibm.com