From: Peter Xu Date: Fri, 20 Jun 2025 15:00:58 +0000 (-0400) Subject: selftests/mm: reduce uffd-unit-test poison test to minimum X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ab7ed56a03ce0196260bc29ab844eb4e54afee66;p=thirdparty%2Flinux.git selftests/mm: reduce uffd-unit-test poison test to minimum The test will still generate quite some unwanted MCE error messages to syslog. There was old proposal ratelimiting the MCE messages from kernel, but that has risk of hiding real useful information on production systems. We can at least reduce the test to minimum to not over-pollute dmesg, however trying to not lose its coverage too much. [peterx@redhat.com: reduce uffd-unit-test poison test to minimum] Link: https://lkml.kernel.org/r/aF2RSsjuEOtzXcUa@x1.local Link: https://lkml.kernel.org/r/20250620150058.1729489-1-peterx@redhat.com Signed-off-by: Peter Xu Cc: Axel Rasmussen Cc: Brendan Jackman Cc: David Hildenbrand Cc: Shuah Khan Signed-off-by: Andrew Morton --- diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index c73fd5d455c83..50501b38e34e7 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -1027,6 +1027,9 @@ static void uffd_poison_handle_fault( do_uffdio_poison(uffd, offset); } +/* Make sure to cover odd/even, and minimum duplications */ +#define UFFD_POISON_TEST_NPAGES 4 + static void uffd_poison_test(uffd_test_args_t *targs) { pthread_t uffd_mon; @@ -1034,12 +1037,17 @@ static void uffd_poison_test(uffd_test_args_t *targs) struct uffd_args args = { 0 }; struct sigaction act = { 0 }; unsigned long nr_sigbus = 0; - unsigned long nr; + unsigned long nr, poison_pages = UFFD_POISON_TEST_NPAGES; + + if (nr_pages < poison_pages) { + uffd_test_skip("Too few pages for POISON test"); + return; + } fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK); - uffd_register_poison(uffd, area_dst, nr_pages * page_size); - memset(area_src, 0, nr_pages * page_size); + uffd_register_poison(uffd, area_dst, poison_pages * page_size); + memset(area_src, 0, poison_pages * page_size); args.handle_fault = uffd_poison_handle_fault; if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) @@ -1051,7 +1059,7 @@ static void uffd_poison_test(uffd_test_args_t *targs) if (sigaction(SIGBUS, &act, 0)) err("sigaction"); - for (nr = 0; nr < nr_pages; ++nr) { + for (nr = 0; nr < poison_pages; ++nr) { unsigned long offset = nr * page_size; const char *bytes = (const char *) area_dst + offset; const char *i; @@ -1078,9 +1086,9 @@ static void uffd_poison_test(uffd_test_args_t *targs) if (pthread_join(uffd_mon, NULL)) err("pthread_join()"); - if (nr_sigbus != nr_pages / 2) + if (nr_sigbus != poison_pages / 2) err("expected to receive %lu SIGBUS, actually received %lu", - nr_pages / 2, nr_sigbus); + poison_pages / 2, nr_sigbus); uffd_test_pass(); }