From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D4EB2CD6E75 for ; Fri, 5 Jun 2026 02:42:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=nQRT4mJ1HgdsNx44mOqyA+8emUgDAkQ/qj+2hj+KmJw=; b=ytSuTViIm3gSOQBG43ETPQVeUe wu40cyvGCsZ7y1f3BsoMbMjjBLdLBSBVmti8doj5oZAj6hw8xiSt1BAwOyWA77LY3XBLmUIZE3eIA Qlilrn07HnFxwk1AcDNBW3ppFKWv29w+efxsRtCD/uozphSMq4+pdN8Bc1Shp6ymzZ3zBIOdbOHqr vjYbT5mpUJAqhE7apZYVSe2sv7OEI7K4QuNpslgvkFiTqVzBAkGADPuhjkPQL6LjtweSynl/rF9W/ TDU6A4B037cC//pXssuX/eJWmLzmHboQL0w+Gcyx0Mvo0OBJFRmvM/Wa4bdtKeI0kHvBlt3eY79Nz W/cq67Ig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wVKWF-0000000Haoo-1Yu4; Fri, 05 Jun 2026 02:42:47 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wVKWC-0000000HaoB-38qD for linux-mediatek@lists.infradead.org; Fri, 05 Jun 2026 02:42:45 +0000 X-UUID: 30fd1c7a608811f1afed4741b24580c9-20260604 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=nQRT4mJ1HgdsNx44mOqyA+8emUgDAkQ/qj+2hj+KmJw=; b=E77qREhmIwi4yNofggsHQ50S1W1TGgE51v2rQand0j8RgMedlli/OAUXASXZdx5TrvlzJjRyYmssSfiq0Pt5TIK5WZOBhlxLwYVfbo0fHHcLUi7WZujpThK1KtoNF4aAN9B2WDIkiETmRiXz66mWeV7zk+kJLFQfF5FxyNWfWuQ=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.15,REQID:075f85dc-de7e-4007-94ab-a4a84d0666de,IP:0,U RL:0,TC:0,Content:-32768,EDM:0,RT:0,SF:-32768,FILE:0,BULK:-32768,RULE:Rele ase_Ham,ACTION:release,TS:0 X-CID-META: VersionHash:e276073,CLOUDID:bad3939b-c398-4479-aea6-536e296bbbcb,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:nil,TC:-5,Content:nil,EDM:-3,IP:nil, URL:0,File:130,RT:0,Bulk:nil,QS:nil,BEC:-1,COL:0,OSI:0,OSA:0,AV:0,LES:1,SP R:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 30fd1c7a608811f1afed4741b24580c9-20260604 Received: from mtkmbs10n2.mediatek.inc [(172.21.101.183)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 295252633; Thu, 04 Jun 2026 19:42:27 -0700 Received: from mtkmbs13n2.mediatek.inc (172.21.101.108) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Fri, 5 Jun 2026 10:42:25 +0800 Received: from mussdccf250.eus.mediatek.inc (10.73.250.250) by mtkmbs13n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.2562.29 via Frontend Transport; Fri, 5 Jun 2026 10:42:24 +0800 From: Ryder Lee To: Felix Fietkau CC: , , Shayne Chen , Ryder Lee Subject: [PATCH] wifi: mt76: fix potential tx_retries underflow Date: Thu, 4 Jun 2026 19:42:22 -0700 Message-ID: <20260605024222.3388222-1-ryder.lee@mediatek.com> X-Mailer: git-send-email 2.45.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260604_194244_819543_A3A35541 X-CRM114-Status: GOOD ( 10.80 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org 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 or 255 for u8). Fix by checking if count is non-zero before subtracting 1. Signed-off-by: Ryder Lee --- drivers/net/wireless/mediatek/mt76/mt7915/mac.c | 10 +++++----- drivers/net/wireless/mediatek/mt76/mt7921/mac.c | 5 +++-- drivers/net/wireless/mediatek/mt76/mt7925/mac.c | 5 +++-- drivers/net/wireless/mediatek/mt76/mt7996/mac.c | 6 +++--- 4 files changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c index cec2c4208..334c19ab2 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); } diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c index 03b4960db..668bfa195 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c +++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c @@ -530,8 +530,9 @@ static void mt7921_mac_tx_free(struct mt792x_dev *dev, void *data, int len) stat = FIELD_GET(MT_TX_FREE_STATUS, info); if (wcid) { - wcid->stats.tx_retries += - FIELD_GET(MT_TX_FREE_COUNT, info) - 1; + u32 count = FIELD_GET(MT_TX_FREE_COUNT, info); + + wcid->stats.tx_retries += count ? count - 1 : 0; wcid->stats.tx_failed += !!stat; } diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c index c47bd812b..c56a9e530 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c +++ b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c @@ -1141,8 +1141,9 @@ mt7925_mac_tx_free(struct mt792x_dev *dev, void *data, int len) if (info & MT_TXFREE_INFO_HEADER) { if (wcid) { - wcid->stats.tx_retries += - FIELD_GET(MT_TXFREE_INFO_COUNT, info) - 1; + u32 count = FIELD_GET(MT_TXFREE_INFO_COUNT, info); + + wcid->stats.tx_retries += count ? count - 1 : 0; wcid->stats.tx_failed += !!FIELD_GET(MT_TXFREE_INFO_STAT, info); } diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c index a59c14c8f..3fad977ba 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c +++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c @@ -1361,13 +1361,13 @@ mt7996_mac_tx_free(struct mt7996_dev *dev, void *data, int len) cur_info++; continue; } else if (info & MT_TXFREE_INFO_HEADER) { - u32 tx_retries = 0, tx_failed = 0; + u32 tx_retries = 0, tx_failed = 0, count; if (!wcid) continue; - tx_retries = - FIELD_GET(MT_TXFREE_INFO_COUNT, info) - 1; + count = FIELD_GET(MT_TXFREE_INFO_COUNT, info); + tx_retries = count ? count - 1 : 0; tx_failed = tx_retries + !!FIELD_GET(MT_TXFREE_INFO_STAT, info); -- 2.45.2