From: Ryder Lee Date: Fri, 5 Jun 2026 11:33:03 +0000 (-0700) Subject: wifi: mt76: mt7915: fix potential tx_retries underflow X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=05e72b6167970043348bfbe8f72a3b67a38a9f1c;p=thirdparty%2Flinux.git wifi: mt76: mt7915: fix potential tx_retries underflow When FIELD_GET returns 0 for the retry count, subtracting 1 causes an unsigned integer underflow, resulting in tx_retries becoming a very large value (0xFFFFFFFF for u32). Fix by checking if count is non-zero before subtracting 1. Fixes: 943e4fb96e6f ("wifi: mt76: mt7915: report tx retries/failed counts for non-WED path") Signed-off-by: Ryder Lee Link: https://patch.msgid.link/20260605113306.3485554-1-ryder.lee@mediatek.com Signed-off-by: Felix Fietkau --- diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c index cec2c4208255..334c19ab2b22 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c +++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c @@ -912,16 +912,16 @@ mt7915_mac_tx_free(struct mt7915_dev *dev, void *data, int len) } if (!mtk_wed_device_active(&mdev->mmio.wed) && wcid) { - u32 tx_retries = 0, tx_failed = 0; + u32 tx_retries = 0, tx_failed = 0, count; if (v3 && (info & MT_TX_FREE_MPDU_HEADER_V3)) { - tx_retries = - FIELD_GET(MT_TX_FREE_COUNT_V3, info) - 1; + count = FIELD_GET(MT_TX_FREE_COUNT_V3, info); + tx_retries = count ? count - 1 : 0; tx_failed = tx_retries + !!FIELD_GET(MT_TX_FREE_STAT_V3, info); } else if (!v3 && (info & MT_TX_FREE_MPDU_HEADER)) { - tx_retries = - FIELD_GET(MT_TX_FREE_COUNT, info) - 1; + count = FIELD_GET(MT_TX_FREE_COUNT, info); + tx_retries = count ? count - 1 : 0; tx_failed = tx_retries + !!FIELD_GET(MT_TX_FREE_STAT, info); }