The buffer bgx_sel used in snprintf() was too small to safely hold the formatted string "BGX%d" for all valid bgx_id values. This caused a -Wformat-truncation warning with `Werror` enabled during build. Increase the buffer size from 5 to 7 and use `sizeof(bgx_sel)` in snprintf() to ensure safety and suppress the warning. Build warning: CC drivers/net/ethernet/cavium/thunder/thunder_bgx.o drivers/net/ethernet/cavium/thunder/thunder_bgx.c: In function ‘bgx_acpi_match_id’: drivers/net/ethernet/cavium/thunder/thunder_bgx.c:1434:27: error: ‘%d’ directive output may be truncated writing between 1 and 3 bytes into a region of size 2 [-Werror=format-truncation=] snprintf(bgx_sel, 5, "BGX%d", bgx->bgx_id); ^~ drivers/net/ethernet/cavium/thunder/thunder_bgx.c:1434:23: note: directive argument in the range [0, 255] snprintf(bgx_sel, 5, "BGX%d", bgx->bgx_id); ^~~~~~~ drivers/net/ethernet/cavium/thunder/thunder_bgx.c:1434:2: note: ‘snprintf’ output between 5 and 7 bytes into a destination of size 5 snprintf(bgx_sel, 5, "BGX%d", bgx->bgx_id); compiler warning due to insufficient snprintf buffer size. Signed-off-by: Alok Tiwari Reviewed-by: Simon Horman --- v2->v3 added Reviewed-by: Simon used bgx_sel[7] as suggested by Jakub Kicinski https://lore.kernel.org/all/20250710153422.6adae255@kernel.org/ v1->v2 No changes. Targeting for net-next. https://lore.kernel.org/all/20250708160957.GQ452973@horms.kernel.org/ --- drivers/net/ethernet/cavium/thunder/thunder_bgx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/cavium/thunder/thunder_bgx.c b/drivers/net/ethernet/cavium/thunder/thunder_bgx.c index 3b7ad744b2dd6..21495b5dce254 100644 --- a/drivers/net/ethernet/cavium/thunder/thunder_bgx.c +++ b/drivers/net/ethernet/cavium/thunder/thunder_bgx.c @@ -1429,9 +1429,9 @@ static acpi_status bgx_acpi_match_id(acpi_handle handle, u32 lvl, { struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL }; struct bgx *bgx = context; - char bgx_sel[5]; + char bgx_sel[7]; - snprintf(bgx_sel, 5, "BGX%d", bgx->bgx_id); + snprintf(bgx_sel, sizeof(bgx_sel), "BGX%d", bgx->bgx_id); if (ACPI_FAILURE(acpi_get_name(handle, ACPI_SINGLE_NAME, &string))) { pr_warn("Invalid link device\n"); return AE_OK; -- 2.46.0