linux/tools/testing/selftests/kselftest.h

490 lines
12 KiB

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 bcb7ee79029d ("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 bcb7ee79029d ("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: e797203fb3ba ("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 15:38:03 +02:00
selftests:resctrl: Fix build failure on archs without __cpuid_count() When resctrl is built on architectures without __cpuid_count() support, build fails. resctrl uses __cpuid_count() defined in kselftest.h. Even though the problem is seen while building resctrl on aarch64, this error can be seen on any platform that doesn't support CPUID. CPUID is a x86/x86-64 feature and code paths with CPUID asm commands will fail to build on all other architectures. All others tests call __cpuid_count() do so from x86/x86_64 code paths when _i386__ or __x86_64__ are defined. resctrl is an exception. Fix the problem by defining __cpuid_count() only when __i386__ or __x86_64__ are defined in kselftest.h and changing resctrl to call __cpuid_count() only when __i386__ or __x86_64__ are defined. In file included from resctrl.h:24, from cat_test.c:11: In function ‘arch_supports_noncont_cat’, inlined from ‘noncont_cat_run_test’ at cat_test.c:326:6: ../kselftest.h:74:9: error: impossible constraint in ‘asm’ 74 | __asm__ __volatile__ ("cpuid\n\t" \ | ^~~~~~~ cat_test.c:304:17: note: in expansion of macro ‘__cpuid_count’ 304 | __cpuid_count(0x10, 1, eax, ebx, ecx, edx); | ^~~~~~~~~~~~~ ../kselftest.h:74:9: error: impossible constraint in ‘asm’ 74 | __asm__ __volatile__ ("cpuid\n\t" \ | ^~~~~~~ cat_test.c:306:17: note: in expansion of macro ‘__cpuid_count’ 306 | __cpuid_count(0x10, 2, eax, ebx, ecx, edx); Fixes: ae638551ab64 ("selftests/resctrl: Add non-contiguous CBMs CAT test") Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Closes: https://lore.kernel.org/lkml/20240809071059.265914-1-usama.anjum@collabora.com/ Reported-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Acked-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2024-09-05 12:02:31 -06:00
selftests:resctrl: Fix build failure on archs without __cpuid_count() When resctrl is built on architectures without __cpuid_count() support, build fails. resctrl uses __cpuid_count() defined in kselftest.h. Even though the problem is seen while building resctrl on aarch64, this error can be seen on any platform that doesn't support CPUID. CPUID is a x86/x86-64 feature and code paths with CPUID asm commands will fail to build on all other architectures. All others tests call __cpuid_count() do so from x86/x86_64 code paths when _i386__ or __x86_64__ are defined. resctrl is an exception. Fix the problem by defining __cpuid_count() only when __i386__ or __x86_64__ are defined in kselftest.h and changing resctrl to call __cpuid_count() only when __i386__ or __x86_64__ are defined. In file included from resctrl.h:24, from cat_test.c:11: In function ‘arch_supports_noncont_cat’, inlined from ‘noncont_cat_run_test’ at cat_test.c:326:6: ../kselftest.h:74:9: error: impossible constraint in ‘asm’ 74 | __asm__ __volatile__ ("cpuid\n\t" \ | ^~~~~~~ cat_test.c:304:17: note: in expansion of macro ‘__cpuid_count’ 304 | __cpuid_count(0x10, 1, eax, ebx, ecx, edx); | ^~~~~~~~~~~~~ ../kselftest.h:74:9: error: impossible constraint in ‘asm’ 74 | __asm__ __volatile__ ("cpuid\n\t" \ | ^~~~~~~ cat_test.c:306:17: note: in expansion of macro ‘__cpuid_count’ 306 | __cpuid_count(0x10, 2, eax, ebx, ecx, edx); Fixes: ae638551ab64 ("selftests/resctrl: Add non-contiguous CBMs CAT test") Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Closes: https://lore.kernel.org/lkml/20240809071059.265914-1-usama.anjum@collabora.com/ Reported-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Acked-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2024-09-05 12:02:31 -06:00
selftests: kselftest: Mark functions that unconditionally call exit() as __noreturn After commit 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()"), clang warns: tools/testing/selftests/timers/../kselftest.h:398:6: warning: variable 'major' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized] 398 | if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2) | ^~~~~~~~~~~~ tools/testing/selftests/timers/../kselftest.h:401:9: note: uninitialized use occurs here 401 | return major > min_major || (major == min_major && minor >= min_minor); | ^~~~~ tools/testing/selftests/timers/../kselftest.h:398:6: note: remove the '||' if its condition is always false 398 | if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2) | ^~~~~~~~~~~~~~~ tools/testing/selftests/timers/../kselftest.h:395:20: note: initialize the variable 'major' to silence this warning 395 | unsigned int major, minor; | ^ | = 0 This is a false positive because if uname() fails, ksft_exit_fail_msg() will be called, which unconditionally calls exit(), a noreturn function. However, clang does not know that ksft_exit_fail_msg() will call exit() at the point in the pipeline that the warning is emitted because inlining has not occurred, so it assumes control flow will resume normally after ksft_exit_fail_msg() is called. Make it clear to clang that all of the functions that call exit() unconditionally in kselftest.h are noreturn transitively by marking them explicitly with '__attribute__((__noreturn__))', which clears up the warning above and any future warnings that may appear for the same reason. Fixes: 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()") Reported-by: John Stultz <jstultz@google.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Shuah Khan <skhan@linuxfoundation.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240411-mark-kselftest-exit-funcs-noreturn-v1-1-b027c948f586@kernel.org Closes: https://lore.kernel.org/all/20240410232637.4135564-2-jstultz@google.com/
2024-04-11 11:45:40 -07:00
selftests: line buffer test program's stdout Patch series "selftests/mm fixes for arm64", v3. Given my on-going work on large anon folios and contpte mappings, I decided it would be a good idea to start running mm selftests to help guard against regressions. However, it soon became clear that I couldn't get the suite to run cleanly on arm64 with a vanilla v6.5-rc1 kernel (perhaps I'm just doing it wrong??), so got stuck in a rabbit hole trying to debug and fix all the issues. Some were down to misconfigurations, but I also found a number of issues with the tests and even a couple of issues with the kernel. This patch (of 8): The selftests runner pipes the test program's stdout to tap_prefix. The presence of the pipe means that the test program sets its stdout to be fully buffered (as aposed to line buffered when directly connected to the terminal). The block buffering means that there is often content in the buffer at fork() time, which causes the output to end up duplicated. This was causing problems for mm:cow where test results were duplicated 20-30x. Solve this by using `stdbuf`, when available to force the test program to use line buffered mode. This means previously printf'ed results are flushed out of the program before any fork(). Additionally, explicitly set line buffer mode in ksft_print_header(), which means that all test programs that use the ksft framework will benefit even if stdbuf is not present on the system. [ryan.roberts@arm.com: add setvbuf() to set buffering mode] Link: https://lkml.kernel.org/r/20230726070655.2713530-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20230724082522.1202616-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20230724082522.1202616-2-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Florent Revest <revest@chromium.org> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-07-24 09:25:15 +01:00
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 bcb7ee79029d ("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 bcb7ee79029d ("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: e797203fb3ba ("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 15:38:03 +02:00