selftests: add tests for pidfd_send_signal()

2019-03-05T16:04:33Z

As suggested by Andrew Morton in [1] add selftests for the new sys_pidfd_send_signal() syscall: /* test_pidfd_send_signal_syscall_support */ Test whether the pidfd_send_signal() syscall is supported and the tests can be run or need to be skipped. /* test_pidfd_send_signal_simple_success */ Test whether sending a signal via a pidfd works. /* test_pidfd_send_signal_exited_fail */ Verify that sending a signal to an already exited process fails with ESRCH. /* test_pidfd_send_signal_recycled_pid_fail */ Verify that a recycled pid cannot be signaled via a pidfd referring to an already exited process that had the same pid (cf. [2], [3]). [1]: https://lore.kernel.org/lkml/20181228152012.dbf0508c2508138efc5f2bbe@linux-foundation.org/ [2]: https://lore.kernel.org/lkml/20181230210245.GA30252@mail.hallyn.com/ [3]: https://lore.kernel.org/lkml/20181230232711.7aayb7vnhogbv4co@brauner.io/ Cc: Arnd Bergmann Cc: "Eric W. Biederman" Cc: Kees Cook Cc: Jann Horn Cc: Andy Lutomirsky Cc: Andrew Morton Cc: Oleg Nesterov Cc: Aleksa Sarai Cc: Al Viro Cc: Florian Weimer Signed-off-by: Christian Brauner Reviewed-by: Tycho Andersen Acked-by: Serge Hallyn

linux/tools/testing/selftests/pidfd, branch v5.1

selftests: add tests for pidfd_send_signal()