The local variable i is used to iterate over unsigned values. The lower bound of the loop is set to 0. While the upper bound is cgx->lmac_count, where they lmac_count is an u8. So the theoretical upper bound is 255. As is, GCC can't see this range of values and warns that a formatted string, which includes the %d representation of i, may overflow the buffer provided. GCC 15.1.0 says: .../cgx.c: In function 'cgx_lmac_init': .../cgx.c:1737:49: warning: '%d' directive writing between 1 and 11 bytes into a region of size between 4 and 6 [-Wformat-overflow=] 1737 | sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i); | ^~ .../cgx.c:1737:37: note: directive argument in the range [-2147483641, 254] 1737 | sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i); | ^~~~~~~~~~~~~~~ .../cgx.c:1737:17: note: 'sprintf' output between 12 and 24 bytes into a destination of size 16 1737 | sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Empirically, changing the type of i from (signed) int to unsigned int addresses this problem. I assume by allowing GCC to see the range of values described above. Also update the format specifiers for the integer values in the string in question from %d to %u. This seems appropriate as they are now both unsigned. No functional change intended. Compile tested only. Signed-off-by: Simon Horman --- drivers/net/ethernet/marvell/octeontx2/af/cgx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c index ab5838865c3f..4ff19a04b23e 100644 --- a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c +++ b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c @@ -1706,9 +1706,9 @@ static int cgx_lmac_init(struct cgx *cgx) { u8 max_dmac_filters; struct lmac *lmac; + int err, filter; + unsigned int i; u64 lmac_list; - int i, err; - int filter; /* lmac_list specifies which lmacs are enabled * when bit n is set to 1, LMAC[n] is enabled @@ -1734,7 +1734,7 @@ static int cgx_lmac_init(struct cgx *cgx) err = -ENOMEM; goto err_lmac_free; } - sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i); + sprintf(lmac->name, "cgx_fwi_%u_%u", cgx->cgx_id, i); if (cgx->mac_ops->non_contiguous_serdes_lane) { lmac->lmac_id = __ffs64(lmac_list); lmac_list &= ~BIT_ULL(lmac->lmac_id);