From patchwork Sat Jun 25 06:47:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 12895251 X-Patchwork-Delegate: kuba@kernel.org 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB6EDC43334 for ; Sat, 25 Jun 2022 06:47:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232148AbiFYGr0 (ORCPT ); Sat, 25 Jun 2022 02:47:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232147AbiFYGrZ (ORCPT ); Sat, 25 Jun 2022 02:47:25 -0400 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4C2542EC2 for ; Fri, 24 Jun 2022 23:47:24 -0700 (PDT) Received: by mail-qv1-xf4a.google.com with SMTP id g7-20020a0ce747000000b0047079ec462dso4619583qvn.20 for ; Fri, 24 Jun 2022 23:47:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=aFuw+d2nCSuOZd/mw7kDFnDj0ODQ6UgWqBH+ZbF/xX8=; b=aWm+kWpU74ZiccOT11I4BcLG4h+utI7VecLRNuPo8d1hdHY8kiFpnfqJi4wvMZ2TIv 2I+rtPQEu5EU25q21smGniE6aX2Iu64vgRRiTCfDsK7CDbBhB16HuA3VzRskzN6+dE4o vM7B21SKkBVgEp/KV0p+qfZFT+JBa0qYt8nvPL/BgKNEegy5ucwCeVV63Evky09ZbnHn hOcyCkngMwoRDLoGu3ae6Xh3KkFCELiwOyLYaRykDWiWfiwMbQRRO+WLV5vXp8B2Tgu/ aD14IuYOfxMSMR8SPyQiZbvIJWZ8E2OT4TP46Wo3+AZnr/FIbulBSfBgpxiWrgfGmqrV znlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=aFuw+d2nCSuOZd/mw7kDFnDj0ODQ6UgWqBH+ZbF/xX8=; b=Dq5Qd+oKWHO5rK4GcZ0A0hVehzP9b+MHpQzDAYIIkAh1ybwY3B/YUKYrkOknHZVI/k UFLR3ZcRCATTCs42zgiFzzysH1JkQNFE5+B9F4on+Ty4ag1P1iNuQksTypimg5Vmk7xk ek9ujsfB39srccgE7K/PG+Yh7eTjqnwckwA91soG32ecfUmVUeA3+x1SoIW/1aX01/9u INeoRSf4FZJM2NJlD4c70RXkvKyl18s6MhNkxmgNm6W5EYGyjsBACwo9HgLcdPxPlXiL 5uaU0RnfwUNlj8DxoNQYNX6Q1PBsvtzxWPKqQ8S88J0aGiShnNOya5K6jiBdsM5os5M1 jMfw== X-Gm-Message-State: AJIora/8U8xJNO/9CH1d0uzVySDsO7maVG7E6bEC1FkacJWBV1AFnGLD 6tL2mcYjtUl/CfoqNx5ADeSxOp+OqXPzhQ== X-Google-Smtp-Source: AGRyM1u/BOTj5k/UzH41LRm2PeSu5E0zY/0e/f1FF4aMyI6DPS2Puht+NSSdDmttD1CqD+/2tE8pQ3v3Tyu23w== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a05:620a:2411:b0:6a7:26bb:f9f8 with SMTP id d17-20020a05620a241100b006a726bbf9f8mr1903319qkn.197.1656139644010; Fri, 24 Jun 2022 23:47:24 -0700 (PDT) Date: Sat, 25 Jun 2022 06:47:22 +0000 Message-Id: <20220625064722.3722045-1-edumazet@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.37.0.rc0.161.g10f37bed90-goog Subject: [PATCH net-next] ipmr: fix a lockdep splat in ipmr_rtm_dumplink() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet , syzbot Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org vif_dev_read() should be used from RCU protected sections only. ipmr_rtm_dumplink() is holding RTNL, so the data structures can not be changed. syzbot reported: net/ipv4/ipmr.c:84 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by syz-executor.4/3068: stack backtrace: CPU: 1 PID: 3068 Comm: syz-executor.4 Not tainted 5.19.0-rc3-syzkaller-00565-g5d04b0b634bb #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 vif_dev_read net/ipv4/ipmr.c:84 [inline] vif_dev_read net/ipv4/ipmr.c:82 [inline] ipmr_fill_vif net/ipv4/ipmr.c:2756 [inline] ipmr_rtm_dumplink+0x1343/0x18c0 net/ipv4/ipmr.c:2866 netlink_dump+0x541/0xc20 net/netlink/af_netlink.c:2275 __netlink_dump_start+0x647/0x900 net/netlink/af_netlink.c:2380 netlink_dump_start include/linux/netlink.h:245 [inline] rtnetlink_rcv_msg+0x73e/0xc90 net/core/rtnetlink.c:6046 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x917/0xe10 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:734 ____sys_sendmsg+0x334/0x810 net/socket.c:2489 ___sys_sendmsg+0xf3/0x170 net/socket.c:2543 __sys_sendmmsg+0x195/0x470 net/socket.c:2629 __do_sys_sendmmsg net/socket.c:2658 [inline] __se_sys_sendmmsg net/socket.c:2655 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2655 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fefd8a89109 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fefd9ca6168 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fefd8b9bf60 RCX: 00007fefd8a89109 RDX: 0000000004924b68 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 00007fefd8ae305d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc346febaf R14: 00007fefd9ca6300 R15: 0000000000022000 Fixes: ebc3197963fc ("ipmr: add rcu protection over (struct vif_device)->dev") Reported-by: syzbot Signed-off-by: Eric Dumazet --- net/ipv4/ipmr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index f095b6c8100bd24262c949390b68865b8b3987c3..73651d17e51f31c8755da6ac3c1c2763a99b1117 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -2753,7 +2753,7 @@ static bool ipmr_fill_vif(struct mr_table *mrt, u32 vifid, struct sk_buff *skb) struct vif_device *vif; vif = &mrt->vif_table[vifid]; - vif_dev = vif_dev_read(vif); + vif_dev = rtnl_dereference(vif->dev); /* if the VIF doesn't exist just continue */ if (!vif_dev) return true;