Oleg Nesterov 6d029c25b7 selftests/timers/posix_timers: Reimplement check_timer_distribution() ... check_timer_distribution() runs ten threads in a busy loop and tries to test that the kernel distributes a process posix CPU timer signal to every thread over time. There is not guarantee that this is true even after commit bcb7ee7902 ("posix-timers: Prefer delivery of signals to the current thread") because that commit only avoids waking up the sleeping process leader thread, but that has nothing to do with the actual signal delivery. As the signal is process wide the first thread which observes sigpending and wins the race to lock sighand will deliver the signal. Testing shows that this hangs on a regular base because some threads never win the race. The comment "This primarily tests that the kernel does not favour any one." is wrong. The kernel does favour a thread which hits the timer interrupt when CLOCK_PROCESS_CPUTIME_ID expires. Rewrite the test so it only checks that the group leader sleeping in join() never receives SIGALRM and the thread which burns CPU cycles receives all signals. In older kernels which do not have commit bcb7ee7902 ("posix-timers: Prefer delivery of signals to the current thread") the test-case fails immediately, the very 1st tick wakes the leader up. Otherwise it quickly succeeds after 100 ticks. CI testing wants to use newer selftest versions on stable kernels. In this case the test is guaranteed to fail. So check in the failure case whether the kernel version is less than v6.3 and skip the test result in that case. [ tglx: Massaged change log, renamed the version check helper ] Fixes: e797203fb3 ("selftests/timers/posix_timers: Test delivery of signals across threads") Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240409133802.GD29396@redhat.com		2024-04-09 17:48:19 +02:00
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crypto/chacha20-s390
cxl	cxl/test: Add support for qos_class checking	2024-02-16 23:20:34 -08:00
fault-injection
ktest	ktest: force $buildonly = 1 for 'make_warnings_file' test type	2024-03-15 12:36:19 -04:00
kunit	linux_kselftest-kunit-fixes-6.9-rc2	2024-03-29 15:35:12 -07:00
memblock	mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER	2024-01-08 15:27:15 -08:00
nvdimm	tools/testing/nvdimm: Disable "missing prototypes / declarations" warnings	2024-01-22 10:41:59 -08:00
radix-tree
scatterlist
selftests	selftests/timers/posix_timers: Reimplement check_timer_distribution()	2024-04-09 17:48:19 +02:00
vsock	vsock/test: print type for SOCK_SEQPACKET	2024-01-25 16:39:21 -08:00