From: Ihor Solodrai <ihor.solodrai@linux.dev>
To: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Eduard Zingerman <eddyz87@gmail.com>
Cc: "Amery Hung" <ameryhung@gmail.com>,
"Mykyta Yatsenko" <yatsenko@meta.com>,
"Alexis Lothoré" <alexis.lothore@bootlin.com>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com
Subject: [PATCH bpf-next v1 12/14] selftests/bpf: Fix array bounds warning in jit_disasm_helpers
Date: Wed, 11 Feb 2026 17:13:54 -0800 [thread overview]
Message-ID: <20260212011356.3266753-13-ihor.solodrai@linux.dev> (raw)
In-Reply-To: <20260212011356.3266753-1-ihor.solodrai@linux.dev>
Compiler cannot infer upper bound for labels.cnt and warns about
potential buffer overflow in snprintf. Add an explicit bounds
check (... && i < MAX_LOCAL_LABELS) in the loop condition to fix the
warning.
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
.../testing/selftests/bpf/jit_disasm_helpers.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/tools/testing/selftests/bpf/jit_disasm_helpers.c b/tools/testing/selftests/bpf/jit_disasm_helpers.c
index febd6b12e372..364c557c5115 100644
--- a/tools/testing/selftests/bpf/jit_disasm_helpers.c
+++ b/tools/testing/selftests/bpf/jit_disasm_helpers.c
@@ -122,15 +122,15 @@ static int disasm_one_func(FILE *text_out, uint8_t *image, __u32 len)
pc += cnt;
}
qsort(labels.pcs, labels.cnt, sizeof(*labels.pcs), cmp_u32);
- for (i = 0; i < labels.cnt; ++i)
- /* gcc is unable to infer upper bound for labels.cnt and assumes
- * it to be U32_MAX. U32_MAX takes 10 decimal digits.
- * snprintf below prints into labels.names[*],
- * which has space only for two digits and a letter.
- * To avoid truncation warning use (i % MAX_LOCAL_LABELS),
- * which informs gcc about printed value upper bound.
- */
- snprintf(labels.names[i], sizeof(labels.names[i]), "L%d", i % MAX_LOCAL_LABELS);
+ /* gcc is unable to infer upper bound for labels.cnt and
+ * assumes it to be U32_MAX. U32_MAX takes 10 decimal digits.
+ * snprintf below prints into labels.names[*], which has space
+ * only for two digits and a letter. To avoid truncation
+ * warning use (i < MAX_LOCAL_LABELS), which informs gcc about
+ * printed value upper bound.
+ */
+ for (i = 0; i < labels.cnt && i < MAX_LOCAL_LABELS; ++i)
+ snprintf(labels.names[i], sizeof(labels.names[i]), "L%d", i);
/* now print with labels */
labels.print_phase = true;
--
2.53.0
next prev parent reply other threads:[~2026-02-12 1:14 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-12 1:13 [PATCH bpf-next v1 00/14] selftests/bpf: Fixes for userspace ASAN Ihor Solodrai
2026-02-12 1:13 ` [PATCH bpf-next v1 01/14] selftests/bpf: Pass through build flags to bpftool and resolve_btfids Ihor Solodrai
2026-02-12 2:39 ` Alexei Starovoitov
2026-02-12 3:08 ` Ihor Solodrai
2026-02-13 0:08 ` Ihor Solodrai
2026-02-12 1:13 ` [PATCH bpf-next v1 02/14] resolve_btfids: Fix memory leaks reported by ASAN Ihor Solodrai
2026-02-12 11:28 ` Jiri Olsa
2026-02-12 1:13 ` [PATCH bpf-next v1 03/14] selftests/bpf: Add DENYLIST.asan Ihor Solodrai
2026-02-12 1:13 ` [PATCH bpf-next v1 04/14] selftests/bpf: Refactor bpf_get_ksyms() trace helper Ihor Solodrai
2026-02-12 11:29 ` Jiri Olsa
2026-02-17 20:42 ` Ihor Solodrai
2026-02-18 13:14 ` Jiri Olsa
2026-02-13 9:56 ` Alexis Lothoré
2026-02-12 1:13 ` [PATCH bpf-next v1 05/14] selftests/bpf: Fix memory leaks in tests Ihor Solodrai
2026-02-12 23:08 ` Eduard Zingerman
2026-02-12 1:13 ` [PATCH bpf-next v1 06/14] selftests/bpf: Fix cleanup in check_fd_array_cnt__fd_array_too_big() Ihor Solodrai
2026-02-12 23:17 ` Eduard Zingerman
2026-02-12 1:13 ` [PATCH bpf-next v1 07/14] veristat: Fix a memory leak for preset ENUMERATOR Ihor Solodrai
2026-02-12 13:37 ` Mykyta Yatsenko
2026-02-12 1:13 ` [PATCH bpf-next v1 08/14] selftests/bpf: Fix use-after-free in xdp_metadata test Ihor Solodrai
2026-02-12 13:40 ` Mykyta Yatsenko
2026-02-12 1:13 ` [PATCH bpf-next v1 09/14] selftests/bpf: Fix double thread join in uprobe_multi_test Ihor Solodrai
2026-02-12 11:29 ` Jiri Olsa
2026-02-12 14:49 ` Mykyta Yatsenko
2026-02-13 16:48 ` Jiri Olsa
2026-02-12 1:13 ` [PATCH bpf-next v1 10/14] selftests/bpf: Fix resource leaks caused by missing cleanups Ihor Solodrai
2026-02-13 0:45 ` Eduard Zingerman
2026-02-12 1:13 ` [PATCH bpf-next v1 11/14] selftests/bpf: Free bpf_object in test_sysctl Ihor Solodrai
2026-02-13 0:54 ` Eduard Zingerman
2026-02-12 1:13 ` Ihor Solodrai [this message]
2026-02-13 1:02 ` [PATCH bpf-next v1 12/14] selftests/bpf: Fix array bounds warning in jit_disasm_helpers Eduard Zingerman
2026-02-12 1:13 ` [PATCH bpf-next v1 13/14] selftests/bpf: Fix out-of-bounds array access bugs reported by ASAN Ihor Solodrai
2026-02-13 1:11 ` Eduard Zingerman
2026-02-17 23:27 ` Ihor Solodrai
2026-02-12 1:13 ` [PATCH bpf-next v1 14/14] selftests/bpf: Check BPFTOOL env var in detect_bpftool_path() Ihor Solodrai
2026-02-12 15:03 ` Mykyta Yatsenko
2026-02-13 10:36 ` Alexis Lothoré
2026-02-12 22:00 ` [PATCH bpf-next v1 00/14] selftests/bpf: Fixes for userspace ASAN Eduard Zingerman
2026-02-12 23:57 ` Ihor Solodrai
2026-02-13 0:23 ` Eduard Zingerman
2026-02-13 16:13 ` Ihor Solodrai
2026-02-13 18:06 ` Eduard Zingerman
2026-02-12 23:26 ` Eduard Zingerman
2026-02-13 17:56 ` Ihor Solodrai
2026-02-13 18:09 ` Eduard Zingerman
2026-02-13 18:29 ` Ihor Solodrai
2026-02-13 18:35 ` Eduard Zingerman
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