From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6874030B53F; Mon, 13 Apr 2026 16:21:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097319; cv=none; b=Vmna+a26d2EbCd/x835ssh8q1296yjTCJ/igWJWrDSpOI813w2U6aDdyD71IrdYwyoa4cjZTDOu31a8YW1QueP1ukUaHyyPZxmX1dSTyGhmo2UzDUxaqr2GbeIl6u9XBhxZfsxSafSAaLmz1pcFnusdzamTC61srZ6qskAyktEI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097319; c=relaxed/simple; bh=ifF5BmNi1pbFyMf/1b/wXDdm8wP5Nchvv6FlZB6vTK8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oy4ispoN6d9gPj/AsEhioNb7j62bxrbV9DsK7rTznH2GpIv0BLPj1D7VmYIb1DC2GtWu/JeDrt2731V6sUpptnIqrGCrzoKUWyYcp+cdQnIEu8O3MxTiNoaEyWK6s6na3IFYi803jG0g4aunwfYwzssMQafrjBxj2/1Ucj2A6w8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HD+6olFv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HD+6olFv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFEFDC2BCB0; Mon, 13 Apr 2026 16:21:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776097319; bh=ifF5BmNi1pbFyMf/1b/wXDdm8wP5Nchvv6FlZB6vTK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HD+6olFvcFlkzUAbGuGuDy15eMIpTtJqLe1FaZXoBSVST7yy6ed1IxbF02CrgCFP2 kXUgk+OxuwAUAMgwiZQ0vHlnOYVk5kei8QXi6JkjCEIpTd/58ik4m4+E4lu0Pk/7gT JzyEjaSyoDPYl5X2RmOhcQh5aWv0FOZjRquXXCQY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Davide Caratti , Jamal Hadi Salim , Petr Machata , Jakub Kicinski Subject: [PATCH 5.15 058/570] net/sched: ets: fix divide by zero in the offload path Date: Mon, 13 Apr 2026 17:53:09 +0200 Message-ID: <20260413155832.614877955@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155830.386096114@linuxfoundation.org> References: <20260413155830.386096114@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davide Caratti commit e35626f610f3d2b7953ccddf6a77453da22b3a9e upstream. Offloading ETS requires computing each class' WRR weight: this is done by averaging over the sums of quanta as 'q_sum' and 'q_psum'. Using unsigned int, the same integer size as the individual DRR quanta, can overflow and even cause division by zero, like it happened in the following splat: Oops: divide error: 0000 [#1] SMP PTI CPU: 13 UID: 0 PID: 487 Comm: tc Tainted: G E 6.19.0-virtme #45 PREEMPT(full) Tainted: [E]=UNSIGNED_MODULE Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:ets_offload_change+0x11f/0x290 [sch_ets] Code: e4 45 31 ff eb 03 41 89 c7 41 89 cb 89 ce 83 f9 0f 0f 87 b7 00 00 00 45 8b 08 31 c0 45 01 cc 45 85 c9 74 09 41 6b c4 64 31 d2 <41> f7 f2 89 c2 44 29 fa 45 89 df 41 83 fb 0f 0f 87 c7 00 00 00 44 RSP: 0018:ffffd0a180d77588 EFLAGS: 00010246 RAX: 00000000ffffff38 RBX: ffff8d3d482ca000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffd0a180d77660 RBP: ffffd0a180d77690 R08: ffff8d3d482ca2d8 R09: 00000000fffffffe R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffe R13: ffff8d3d472f2000 R14: 0000000000000003 R15: 0000000000000000 FS: 00007f440b6c2740(0000) GS:ffff8d3dc9803000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000003cdd2000 CR3: 0000000007b58002 CR4: 0000000000172ef0 Call Trace: ets_qdisc_change+0x870/0xf40 [sch_ets] qdisc_create+0x12b/0x540 tc_modify_qdisc+0x6d7/0xbd0 rtnetlink_rcv_msg+0x168/0x6b0 netlink_rcv_skb+0x5c/0x110 netlink_unicast+0x1d6/0x2b0 netlink_sendmsg+0x22e/0x470 ____sys_sendmsg+0x38a/0x3c0 ___sys_sendmsg+0x99/0xe0 __sys_sendmsg+0x8a/0xf0 do_syscall_64+0x111/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f440b81c77e Code: 4d 89 d8 e8 d4 bc 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa RSP: 002b:00007fff951e4c10 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000481820 RCX: 00007f440b81c77e RDX: 0000000000000000 RSI: 00007fff951e4cd0 RDI: 0000000000000003 RBP: 00007fff951e4c20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff951f4fa8 R13: 00000000699ddede R14: 00007f440bb01000 R15: 0000000000486980 Modules linked in: sch_ets(E) netdevsim(E) ---[ end trace 0000000000000000 ]--- RIP: 0010:ets_offload_change+0x11f/0x290 [sch_ets] Code: e4 45 31 ff eb 03 41 89 c7 41 89 cb 89 ce 83 f9 0f 0f 87 b7 00 00 00 45 8b 08 31 c0 45 01 cc 45 85 c9 74 09 41 6b c4 64 31 d2 <41> f7 f2 89 c2 44 29 fa 45 89 df 41 83 fb 0f 0f 87 c7 00 00 00 44 RSP: 0018:ffffd0a180d77588 EFLAGS: 00010246 RAX: 00000000ffffff38 RBX: ffff8d3d482ca000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffd0a180d77660 RBP: ffffd0a180d77690 R08: ffff8d3d482ca2d8 R09: 00000000fffffffe R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffe R13: ffff8d3d472f2000 R14: 0000000000000003 R15: 0000000000000000 FS: 00007f440b6c2740(0000) GS:ffff8d3dc9803000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000003cdd2000 CR3: 0000000007b58002 CR4: 0000000000172ef0 Kernel panic - not syncing: Fatal exception Kernel Offset: 0x30000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception ]--- Fix this using 64-bit integers for 'q_sum' and 'q_psum'. Cc: stable@vger.kernel.org Fixes: d35eb52bd2ac ("net: sch_ets: Make the ETS qdisc offloadable") Signed-off-by: Davide Caratti Reviewed-by: Jamal Hadi Salim Reviewed-by: Petr Machata Link: https://patch.msgid.link/28504887df314588c7255e9911769c36f751edee.1771964872.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_ets.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/net/sched/sch_ets.c +++ b/net/sched/sch_ets.c @@ -115,12 +115,12 @@ static void ets_offload_change(struct Qd struct ets_sched *q = qdisc_priv(sch); struct tc_ets_qopt_offload qopt; unsigned int w_psum_prev = 0; - unsigned int q_psum = 0; - unsigned int q_sum = 0; unsigned int quantum; unsigned int w_psum; unsigned int weight; unsigned int i; + u64 q_psum = 0; + u64 q_sum = 0; if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc) return; @@ -138,8 +138,12 @@ static void ets_offload_change(struct Qd for (i = 0; i < q->nbands; i++) { quantum = q->classes[i].quantum; - q_psum += quantum; - w_psum = quantum ? q_psum * 100 / q_sum : 0; + if (quantum) { + q_psum += quantum; + w_psum = div64_u64(q_psum * 100, q_sum); + } else { + w_psum = 0; + } weight = w_psum - w_psum_prev; w_psum_prev = w_psum;