From nobody Sun Feb 8 22:05:33 2026 Received: from mail-pl1-f170.google.com (mail-pl1-f170.google.com [209.85.214.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 37AE2331218 for ; Thu, 13 Nov 2025 08:25:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763022307; cv=none; b=cErWS0a/Kc1iH2xuNk5ctWPBomckmagC46aY1DHZqvIuXcDNQ4hz6C5tJX1Ymy0aHnaK/izE63ByPMpO0fgz6y6niTzbEDtbXxx8+87MiZD05JPLlSO5ZIs4D/J/TBin1HVM0MUldmfvOM2B+CyTp9HUi5ap9IKHnYl5GV56PyY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763022307; c=relaxed/simple; bh=ASn6eNnuIgRormpyUsdH6xwC8Nqx0mzecpZWGz0e2dU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=svCyJDBiJpm0KgBSai0HbX6+/X6NdbJP0OHDK/jmDKdG9jhQHHR6zd8rKZ9uGNCJgBIFIU7i4nEK0vE4XfgY8VZ7BNPjKF9Wv0vgIYu+gVeBL9ZCsNrX8EgqkdfbcAs2btcp0ZT49peoN1nnNXSM0dOBVJx9uX3gannawnpoo6o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Jy2WPtuh; arc=none smtp.client-ip=209.85.214.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Jy2WPtuh" Received: by mail-pl1-f170.google.com with SMTP id d9443c01a7336-29516a36affso5055245ad.3 for ; Thu, 13 Nov 2025 00:25:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1763022305; x=1763627105; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=c2Vq2BmnKQvLB9ANORATdvl80Wcge/HWspHRWqnzzDI=; b=Jy2WPtuh2nMwCnSP1Xgn87igEEYh1G2oaUL8mw1zIXuTu9rqE05XZ363oxDo1BN3jR DsZMDdCJ4HrfPfnoxWK8y3AV61AF3/j34qS9mHhbCbyWgMhMDyJgbZ5jPlX8UeXDy4Of QkvrczUkdaN+GgLcBTG6qoG1NcazLtPMiDUQVSAj4eN9ryF62I+ZtjJsy2hjgFX0Gey3 9uvINSw+2nKqL7VuI4V8TY6xv2IJ8hwThZm2JEjGXBPp2QO04tI5PvNXT+wfIT27hwlF 9UNlOVXzZkmbXI3a27y3T42zbNQQ0IsdY0uAqQPICTO2UgxSvj3UAQcCmiwxn5Ke/oh5 xsNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763022305; x=1763627105; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=c2Vq2BmnKQvLB9ANORATdvl80Wcge/HWspHRWqnzzDI=; b=LR6Ht3kX2qYtBaKdf4tWKnkpm2YRgoekFbhVBXhpfJvkYQ59Ek8ukKdCjKP2JuJdjt dQmkwNgXHOMcyHCt7a6yNCNieBfOGhQYUbxmgrHlOqfL5kZ310w6LWksyAhdnPaq9xNa ESZ1X6Do2BleNmM8esncS+ttGugDSRKYIfnNxzZwW5nUjCr0Kg7ovmQdR8FMaePQrART C8Suic023HtTcS0VID7KrJbocbP3LtKZ7G8Qkruw7t7JwUJA8e+frq68yhKvRPa5YZ0+ TU6UhlsLgeM7zsCl2/FJ8YcEbP/1P+IwfgcCIQgZvFhDZimyfJRmFQ+9aphkCJaVW8kD nKFg== X-Forwarded-Encrypted: i=1; AJvYcCU6fWgI4QmF9Hg0erNa+4MtZ7PtLqGbQSW2CeNslxpgb2dFIGIJDpnyAnkM2FyaiJK546aekOldjjrRn/I=@vger.kernel.org X-Gm-Message-State: AOJu0YwbMLQ4+H/JW9G+xvZiTkK/erbDkPCn+VuBadEbS2apzvSG5OMY SX3c6MmCeuvDqX6ZXTgU+t80p92zHnKGnNUqN/cY7QG7ZHvOlPH3yEbs X-Gm-Gg: ASbGncu3JfLuo24GaMYsCJtK/Vv8JORs1VJW8nxCPtwq8SJsdaK7lYPmdrgLQTszQx+ vHVQfpbuDBejXYfPksPC4BEQaXV8H+OeQ1pGtMnIJdbbzQxVdEckj/OypYrgGMKxafyStByVLYG bf472Umbmpvf5LJCkvsagtSKTFPFGEybzGTDNYKKSYevDENFrY1XR37t3BttdBMqdllj2xhEeKc qQgA6qcs05bbiP9YpoQqMHaHMw1C5GwfafhUC7bQlIz4/nTdpMzIu3BMMm53sjUQUnH07rq0s8/ CjBZaMDuKDw9omsTa3ZjRD23lYd2QSperplrt2tWO9HLHgN/GTA6N27NOl8EJO+1gCRs2SS9qmy 10qciTmYyS3BJkrPb6yp9VkEC4Eo2kqL97g7jd+Ab2WdG6Nk4mhqtH2wAEY5MZJQ9D88BR5E7XB LmoqZglq0Pyn8O8EVNU7g/Ur07VWmL X-Google-Smtp-Source: AGHT+IFXizcARCS/diK1PZXRsemIs1ftqhmJcVBI4KtunVNztQqrVg0rbzvArEDy3g5s3UcskoRzMA== X-Received: by 2002:a17:902:ebd2:b0:298:43f4:cc4b with SMTP id d9443c01a7336-2984ed77d8bmr73236215ad.26.1763022305379; Thu, 13 Nov 2025 00:25:05 -0800 (PST) Received: from localhost.localdomain ([103.246.102.164]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2985c2b1055sm16332635ad.59.2025.11.13.00.24.59 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 13 Nov 2025 00:25:05 -0800 (PST) From: Alessandro Decina To: netdev@vger.kernel.org Cc: Maciej Fijalkowski , "David S. Miller" , Alexei Starovoitov , Andrew Lunn , Daniel Borkmann , Eric Dumazet , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend , Paolo Abeni , Przemek Kitszel , Stanislav Fomichev , Tirthendu Sarkar , Tony Nguyen , bpf@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org, Alessandro Decina Subject: [PATCH net v3 1/1] i40e: xsk: advance next_to_clean on status descriptors Date: Thu, 13 Nov 2025 19:24:38 +1100 Message-Id: <20251113082438.54154-2-alessandro.d@gmail.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20251113082438.54154-1-alessandro.d@gmail.com> References: <20251113082438.54154-1-alessandro.d@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Whenever a status descriptor is received, i40e processes and skips over it, correctly updating next_to_process but forgetting to update next_to_clean. In the next iteration this accidentally causes the creation of an invalid multi-buffer xdp_buff where the first fragment is the status descriptor. If then a skb is constructed from such an invalid buffer - because the eBPF program returns XDP_PASS - a panic occurs: [ 5866.367317] BUG: unable to handle page fault for address: ffd31c37eab1c9= 80 [ 5866.375050] #PF: supervisor read access in kernel mode [ 5866.380825] #PF: error_code(0x0000) - not-present page [ 5866.386602] PGD 0 [ 5866.388867] Oops: Oops: 0000 [#1] SMP NOPTI [ 5866.393575] CPU: 34 UID: 0 PID: 0 Comm: swapper/34 Not tainted 6.17.0-cu= stom #1 PREEMPT(voluntary) [ 5866.403740] Hardware name: Supermicro AS -2115GT-HNTR/H13SST-G, BIOS 3.2= 03/20/2025 [ 5866.412339] RIP: 0010:memcpy+0x8/0x10 [ 5866.416454] Code: cc cc 90 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc = 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 48 89 f8 48 89 d1 a4 e9 fc 26 c0 fe 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 [ 5866.437538] RSP: 0018:ff428d9ec0bb0ca8 EFLAGS: 00010286 [ 5866.443415] RAX: ff2dd26dbd8f0000 RBX: ff2dd265ad161400 RCX: 00000000000= 004e1 [ 5866.451435] RDX: 00000000000004e1 RSI: ffd31c37eab1c980 RDI: ff2dd26dbd8= f0000 [ 5866.459454] RBP: ff428d9ec0bb0d40 R08: 0000000000000000 R09: 00000000000= 00000 [ 5866.467470] R10: 0000000000000000 R11: 0000000000000000 R12: ff428d9eec7= 26ef8 [ 5866.475490] R13: ff2dd26dbd8f0000 R14: ff2dd265ca2f9fc0 R15: ff2dd265485= 48b80 [ 5866.483509] FS: 0000000000000000(0000) GS:ff2dd2c363592000(0000) knlGS:= 0000000000000000 [ 5866.492600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5866.499060] CR2: ffd31c37eab1c980 CR3: 0000000178d7b040 CR4: 0000000000f= 71ef0 [ 5866.507079] PKRU: 55555554 [ 5866.510125] Call Trace: [ 5866.512867] [ 5866.515132] ? i40e_clean_rx_irq_zc+0xc50/0xe60 [i40e] [ 5866.520921] i40e_napi_poll+0x2d8/0x1890 [i40e] [ 5866.526022] ? srso_alias_return_thunk+0x5/0xfbef5 [ 5866.531408] ? raise_softirq+0x24/0x70 [ 5866.535623] ? srso_alias_return_thunk+0x5/0xfbef5 [ 5866.541011] ? srso_alias_return_thunk+0x5/0xfbef5 [ 5866.546397] ? rcu_sched_clock_irq+0x225/0x1800 [ 5866.551493] __napi_poll+0x30/0x230 [ 5866.555423] net_rx_action+0x20b/0x3f0 [ 5866.559643] handle_softirqs+0xe4/0x340 [ 5866.563962] __irq_exit_rcu+0x10e/0x130 [ 5866.568283] irq_exit_rcu+0xe/0x20 [ 5866.572110] common_interrupt+0xb6/0xe0 [ 5866.576425] [ 5866.578791] Advance next_to_clean to ensure invalid xdp_buff(s) aren't created. Rename i40e_inc_ntp to i40e_inc_ntp_ntc. Make it take an optional pointer to next_to_clean so it's harder for callers to accidentally forget to advance it. Fixes: 1c9ba9c14658 ("i40e: xsk: add RX multi-buffer support") Signed-off-by: Alessandro Decina Reviewed-by: Aleksandr Loktionov --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 33 ++++++++++++------- .../ethernet/intel/i40e/i40e_txrx_common.h | 2 ++ drivers/net/ethernet/intel/i40e/i40e_xsk.c | 17 ++++++---- 3 files changed, 34 insertions(+), 18 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethe= rnet/intel/i40e/i40e_txrx.c index cc0b9efc2637..d3dae895a058 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -2359,15 +2359,24 @@ void i40e_finalize_xdp_rx(struct i40e_ring *rx_ring= , unsigned int xdp_res) } =20 /** - * i40e_inc_ntp: Advance the next_to_process index + * i40e_inc_ntp_ntc: Advance the next_to_process and next_to_clean indexes * @rx_ring: Rx ring + * @next_to_process: Pointer to next_to_process + * @next_to_clean: Pointer to next_to_clean or NULL + * + * This function advances the next_to_process index. If next_to_clean is n= ot + * NULL, it is advanced as well. **/ -static void i40e_inc_ntp(struct i40e_ring *rx_ring) +void i40e_inc_ntp_ntc(struct i40e_ring *rx_ring, u16 *next_to_process, + u16 *next_to_clean) { - u32 ntp =3D rx_ring->next_to_process + 1; + u16 ntp =3D *next_to_process + 1; =20 ntp =3D (ntp < rx_ring->count) ? ntp : 0; - rx_ring->next_to_process =3D ntp; + *next_to_process =3D ntp; + if (next_to_clean) + *next_to_clean =3D ntp; + prefetch(I40E_RX_DESC(rx_ring, ntp)); } =20 @@ -2484,17 +2493,19 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_r= ing, int budget, i40e_clean_programming_status(rx_ring, rx_desc->raw.qword[0], qword); + bool eop; + rx_buffer =3D i40e_rx_bi(rx_ring, ntp); - i40e_inc_ntp(rx_ring); - i40e_reuse_rx_page(rx_ring, rx_buffer); /* Update ntc and bump cleaned count if not in the * middle of mb packet. */ - if (rx_ring->next_to_clean =3D=3D ntp) { - rx_ring->next_to_clean =3D - rx_ring->next_to_process; + eop =3D rx_ring->next_to_process =3D=3D + rx_ring->next_to_clean; + i40e_inc_ntp_ntc(rx_ring, &rx_ring->next_to_process, + eop ? &rx_ring->next_to_clean : NULL); + if (eop) cleaned_count++; - } + i40e_reuse_rx_page(rx_ring, rx_buffer); continue; } =20 @@ -2507,7 +2518,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_rin= g, int budget, rx_buffer =3D i40e_get_rx_buffer(rx_ring, size); =20 neop =3D i40e_is_non_eop(rx_ring, rx_desc); - i40e_inc_ntp(rx_ring); + i40e_inc_ntp_ntc(rx_ring, &rx_ring->next_to_process, NULL); =20 if (!xdp->data) { unsigned char *hard_start; diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h b/drivers/n= et/ethernet/intel/i40e/i40e_txrx_common.h index e26807fd2123..3d7e4b3404f0 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h @@ -17,6 +17,8 @@ void i40e_update_rx_stats(struct i40e_ring *rx_ring, unsigned int total_rx_packets); void i40e_finalize_xdp_rx(struct i40e_ring *rx_ring, unsigned int xdp_res); void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val); +void i40e_inc_ntp_ntc(struct i40e_ring *rx_ring, u16 *next_to_process, + u16 *next_to_clean); =20 #define I40E_XDP_PASS 0 #define I40E_XDP_CONSUMED BIT(0) diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ether= net/intel/i40e/i40e_xsk.c index 9f47388eaba5..fdf72446ed67 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -410,7 +410,6 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int= budget) u16 next_to_clean =3D rx_ring->next_to_clean; unsigned int xdp_res, xdp_xmit =3D 0; struct xdp_buff *first =3D NULL; - u32 count =3D rx_ring->count; struct bpf_prog *xdp_prog; u32 entries_to_alloc; bool failure =3D false; @@ -430,6 +429,7 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int= budget) struct xdp_buff *bi; unsigned int size; u64 qword; + bool neop; =20 rx_desc =3D I40E_RX_DESC(rx_ring, next_to_process); qword =3D le64_to_cpu(rx_desc->wb.qword1.status_error_len); @@ -446,8 +446,10 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, in= t budget) qword); bi =3D *i40e_rx_bi(rx_ring, next_to_process); xsk_buff_free(bi); - if (++next_to_process =3D=3D count) - next_to_process =3D 0; + i40e_inc_ntp_ntc(rx_ring, &next_to_process, + next_to_process =3D=3D next_to_clean ? + &next_to_clean : + NULL); continue; } =20 @@ -466,16 +468,17 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, i= nt budget) break; } =20 - if (++next_to_process =3D=3D count) - next_to_process =3D 0; + neop =3D i40e_is_non_eop(rx_ring, rx_desc); + // advance next_to_process. on EOP, advance next_to_clean as well. + i40e_inc_ntp_ntc(rx_ring, &next_to_process, + !neop ? &next_to_clean : NULL); =20 - if (i40e_is_non_eop(rx_ring, rx_desc)) + if (neop) continue; =20 xdp_res =3D i40e_run_xdp_zc(rx_ring, first, xdp_prog); i40e_handle_xdp_result_zc(rx_ring, first, rx_desc, &rx_packets, &rx_bytes, xdp_res, &failure); - next_to_clean =3D next_to_process; if (failure) break; total_rx_packets +=3D rx_packets; --=20 2.43.0