From: Gregory Bell Date: Tue, 17 Feb 2026 14:32:36 +0000 (-0500) Subject: selftests/bpf: fix flaky build_id test X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d820fa3114825c43a6a2f3d66d3d1029db811fe3;p=thirdparty%2Flinux.git selftests/bpf: fix flaky build_id test The build_id selftest occasionally fails because MADV_PAGEOUT does not guarantee the immediate eviction of the page. The test assumes eviction happens and proceeds without verifying that the page was actually reclaimed, leading to false test failures. Fix the test by retrying the page-out sequence until eviction is successful, instead of relying on a single MADV_PAGEOUT attempt. Signed-off-by: Gregory Bell Link: https://lore.kernel.org/r/038bd27c69dd3a16958894fcb19e4fb6fbfe317e.1771338492.git.grbell@redhat.com Signed-off-by: Alexei Starovoitov --- diff --git a/tools/testing/selftests/bpf/uprobe_multi.c b/tools/testing/selftests/bpf/uprobe_multi.c index dd38dc68f6359..3e58a86b8e254 100644 --- a/tools/testing/selftests/bpf/uprobe_multi.c +++ b/tools/testing/selftests/bpf/uprobe_multi.c @@ -100,6 +100,9 @@ int __attribute__((weak)) trigger_uprobe(bool build_id_resident) int page_sz = sysconf(_SC_PAGESIZE); void *addr; + unsigned char vec[1]; + int poll = 0; + /* page-align build ID start */ addr = (void *)((uintptr_t)&build_id_start & ~(page_sz - 1)); @@ -108,9 +111,19 @@ int __attribute__((weak)) trigger_uprobe(bool build_id_resident) * do MADV_POPULATE_READ, and then MADV_PAGEOUT, if necessary */ madvise(addr, page_sz, MADV_POPULATE_READ); - if (!build_id_resident) - madvise(addr, page_sz, MADV_PAGEOUT); - + if (!build_id_resident) { + do { + madvise(addr, page_sz, MADV_PAGEOUT); + /* check if page has been evicted */ + mincore(addr, page_sz, vec); + if (!(vec[0] & 1)) + break; + /* if page is still resident re-attempt MADV_POPULATE_READ/MADV_PAGEOUT */ + madvise(addr, page_sz, MADV_POPULATE_READ); + poll++; + usleep(100); + } while (poll < 500); + } (void)uprobe(); return 0;