From dcd164ec67f89e0db5ee025ee9e91280052eb737 Mon Sep 17 00:00:00 2001 From: Viktor Malik Date: Wed, 15 Jul 2026 13:22:02 +0200 Subject: [PATCH] selftests/bpf: Silence array bounds warning in global_map_resize MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When compiling BPF selftests with -O2, GCC reports an array bounds violation warning in global_map_resize test: In function ‘global_map_resize_bss_subtest’, inlined from ‘test_global_map_resize’ at /bpf-next/tools/testing/selftests/bpf/prog_tests/global_map_resize.c:228:3: /bpf-next/tools/testing/selftests/bpf/prog_tests/global_map_resize.c:64:33: error: array subscript 1 is above array bounds of ‘int[1]’ [-Werror=array-bounds=] 64 | skel->bss->array[i] = 1; | ~~~~~~~~~~~~~~~~^~~ In file included from /bpf-next/tools/testing/selftests/bpf/prog_tests/global_map_resize.c:6: ./test_global_map_resize.skel.h: In function ‘test_global_map_resize’: ./test_global_map_resize.skel.h:44:21: note: while referencing ‘array’ 44 | int array[1]; | ^~~~~ This is a false positive because `array` (a BPF map) has been resized from within the BPF program. GCC doesn't know that so let us silence the warning by accessing the array via a plain pointer. Fixes: 08b089567573 ("libbpf: Selftests for resizing datasec maps") Signed-off-by: Viktor Malik Link: https://lore.kernel.org/bpf/57765bc465a27923c3c093eba222cc24d08d8c40.1784112948.git.vmalik@redhat.com Signed-off-by: Kumar Kartikeya Dwivedi --- .../testing/selftests/bpf/prog_tests/global_map_resize.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/global_map_resize.c b/tools/testing/selftests/bpf/prog_tests/global_map_resize.c index 56b5baef35c8..602ce30f1720 100644 --- a/tools/testing/selftests/bpf/prog_tests/global_map_resize.c +++ b/tools/testing/selftests/bpf/prog_tests/global_map_resize.c @@ -23,6 +23,7 @@ static void global_map_resize_bss_subtest(void) struct bpf_map *map; const __u32 desired_sz = sizeof(skel->bss->sum) + sysconf(_SC_PAGE_SIZE) * 2; size_t array_len, actual_sz, new_sz; + int *array; skel = test_global_map_resize__open(); if (!ASSERT_OK_PTR(skel, "test_global_map_resize__open")) @@ -58,10 +59,13 @@ static void global_map_resize_bss_subtest(void) goto teardown; /* fill the newly resized array with ones, - * skipping the first element which was previously set + * skipping the first element which was previously set; + * access through a plain pointer to avoid -Warray-bounds + * since the array was resized beyond its declared length. */ + array = skel->bss->array; for (int i = 1; i < array_len; i++) - skel->bss->array[i] = 1; + array[i] = 1; /* set global const values before loading */ skel->rodata->pid = getpid();