From patchwork Tue Mar 30 06:45:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 412319 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D0E4C433C1 for ; Tue, 30 Mar 2021 06:46:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7003861983 for ; Tue, 30 Mar 2021 06:46:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231191AbhC3GqK (ORCPT ); Tue, 30 Mar 2021 02:46:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230202AbhC3Gp4 (ORCPT ); Tue, 30 Mar 2021 02:45:56 -0400 Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17765C061762 for ; Mon, 29 Mar 2021 23:45:56 -0700 (PDT) Received: by mail-pg1-x52f.google.com with SMTP id p12so6363133pgj.10 for ; Mon, 29 Mar 2021 23:45:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=KZP75OjQry/uPdKjzimKTM/OAfV058mi27NbCAn/2pg=; b=jdhZy5I7jMWKREhbyPGHBFCUvvl7zLTXjMzAjsoeshwb1aUqSUk/y8cd1Q6z8ey59D ZgYsAyFFffmt4L95Aqz5PCVzIEmEWjX7TtToQfv797kfOxwe5rYl3If0PjWDuaxxZxjP uTrr5Pdgiq2hYdqwqiMfX5UdKV95GL9OwmJQPk45c+ta2D9PQhzJdtdx85nTGMpFMkke zcolgJjyskKlYDzYFX8NlMDN+et2KZp6tgrOq/apqKhYwmMGPXNIfCEdByIiO9KvuzV2 0gcsp5Mq/qNVE2xwXuMzUEFSyNJ4DWFsYgf0FvP3mO5qFxeW/484O6aoIHXumuo89igP BKAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=KZP75OjQry/uPdKjzimKTM/OAfV058mi27NbCAn/2pg=; b=RQvP4liUJtehDgvjTn2zj1BI6KFHhnYlQYu7NuHZMBUzdQ2jvBkiAj3UhtS1zC72js +xtErBVe4dWtA3FS9Bt3E4tVHyuv2wjol4taENJ0bX1vMskCGM/NV8Gd/a1mFCHvE9Op vQtDuTWb95M5VxC+ZCv/VAhWadGntbFo24VrpYFTK4+i8sDGjsJtraaXdISfI0W4b5wZ 9hLSxdfGVIZk+Z7Zbqujd8BSaUTPWpvwdLFVj+phv5t6KMPUMcDVu5TZzSkTtfEm2jtd 6yNJKJwfnDY/40t9Uai53LWPWn0DIo7JzOngRFXUpWzG81+VWM/yyP3Zw+H4IK/2miQP A+eA== X-Gm-Message-State: AOAM532+fj6zyanDPd6SNjBGa4Ao+YwGcxSx07Dv94ImWkZjLymrrVof DGdnx9VTTIa3maVAlwtpBiE= X-Google-Smtp-Source: ABdhPJyoIKXAyJh5JC7i7hSizaw2TTHhSZD8dL4N5AyLtgPDhUGPxQZtjqbDjTjqeWXkQohC6f9XNw== X-Received: by 2002:a63:4462:: with SMTP id t34mr26619062pgk.389.1617086755659; Mon, 29 Mar 2021 23:45:55 -0700 (PDT) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:78a0:7565:129d:828c]) by smtp.gmail.com with ESMTPSA id y20sm19286714pfo.210.2021.03.29.23.45.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Mar 2021 23:45:55 -0700 (PDT) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski Cc: netdev , Eric Dumazet , Eric Dumazet , syzbot Subject: [PATCH net-next] ip6_tunnel: sit: proper dev_{hold|put} in ndo_[un]init methods Date: Mon, 29 Mar 2021 23:45:51 -0700 Message-Id: <20210330064551.545964-1-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.31.0.291.g576ba9dcdaf-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet Same reasons than for the previous commits : 6289a98f0817 ("sit: proper dev_{hold|put} in ndo_[un]init methods") 40cb881b5aaa ("ip6_vti: proper dev_{hold|put} in ndo_[un]init methods") 7f700334be9a ("ip6_gre: proper dev_{hold|put} in ndo_[un]init methods") After adopting CONFIG_PCPU_DEV_REFCNT=n option, syzbot was able to trigger a warning [1] Issue here is that: - all dev_put() should be paired with a corresponding prior dev_hold(). - A driver doing a dev_put() in its ndo_uninit() MUST also do a dev_hold() in its ndo_init(), only when ndo_init() is returning 0. Otherwise, register_netdevice() would call ndo_uninit() in its error path and release a refcount too soon. [1] WARNING: CPU: 1 PID: 21059 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 Modules linked in: CPU: 1 PID: 21059 Comm: syz-executor.4 Not tainted 5.12.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31 Code: 1d 6a 5a e8 09 31 ff 89 de e8 8d 1a ab fd 84 db 75 e0 e8 d4 13 ab fd 48 c7 c7 a0 e1 c1 89 c6 05 4a 5a e8 09 01 e8 2e 36 fb 04 <0f> 0b eb c4 e8 b8 13 ab fd 0f b6 1d 39 5a e8 09 31 ff 89 de e8 58 RSP: 0018:ffffc900025aefe8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000040000 RSI: ffffffff815c51f5 RDI: fffff520004b5def RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815bdf8e R11: 0000000000000000 R12: ffff888023488568 R13: ffff8880254e9000 R14: 00000000dfd82cfd R15: ffff88802ee2d7c0 FS: 00007f13bc590700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0943e74000 CR3: 0000000025273000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_dec include/linux/refcount.h:344 [inline] refcount_dec include/linux/refcount.h:359 [inline] dev_put include/linux/netdevice.h:4135 [inline] ip6_tnl_dev_uninit+0x370/0x3d0 net/ipv6/ip6_tunnel.c:387 register_netdevice+0xadf/0x1500 net/core/dev.c:10308 ip6_tnl_create2+0x1b5/0x400 net/ipv6/ip6_tunnel.c:263 ip6_tnl_newlink+0x312/0x580 net/ipv6/ip6_tunnel.c:2052 __rtnl_newlink+0x1062/0x1710 net/core/rtnetlink.c:3443 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 919067cc845f ("net: add CONFIG_PCPU_DEV_REFCNT") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Eric Dumazet Reported-by: syzbot --- net/ipv6/ip6_tunnel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index cd78f5b2cd75e20a79fd6c4cbfafd548204c2b7c..67ee9d58ec5efcc81e8b27406bd4f57a0caea70b 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -266,7 +266,6 @@ static int ip6_tnl_create2(struct net_device *dev) strcpy(t->parms.name, dev->name); - dev_hold(dev); ip6_tnl_link(ip6n, t); return 0; @@ -1882,6 +1881,7 @@ ip6_tnl_dev_init_gen(struct net_device *dev) dev->min_mtu = ETH_MIN_MTU; dev->max_mtu = IP6_MAX_MTU - dev->hard_header_len; + dev_hold(dev); return 0; destroy_dst: