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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 73CF3C433DF for ; Mon, 29 Jun 2020 19:35:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47E59206E2 for ; Mon, 29 Jun 2020 19:35:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593459315; bh=VS1CPfZGGl3IXFs3WZontZttp1TBg5R/bIFBI+ppRM4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YCOdBJVIDhfrJJkdQGb4IzIggft8RbV69HjcU7+eP1733pc2yIvCT/uRd7OUbTttI tS3y6WRRn8Sk1uSZ3rroYkQGJ07M9DUmHNxig+fE+bv0kr6DTneSPYfj1fxGqDjyoU odBnRgpaAUnYQTROPFfvEVJGE8pPnBilj2fDhWjQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733122AbgF2TbS (ORCPT ); Mon, 29 Jun 2020 15:31:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:40568 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732687AbgF2Tad (ORCPT ); Mon, 29 Jun 2020 15:30:33 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 48D13252E6; Mon, 29 Jun 2020 15:38:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593445116; bh=VS1CPfZGGl3IXFs3WZontZttp1TBg5R/bIFBI+ppRM4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rcYFLq2mFBehsid0JInu6MTBf6IJiaRHNOi2XtfS1rdIKBzemdGE3drAdXmRQJ/Sd mIMatbU/65TbiDC4BCneLbiZ1zgjdTVj8lhUnTrzFdskTwlzZnr+ymw9/0ssW1sSBJ Obn7pKr7jVKC344PP1Ms2Z5lOjad1qvWUd4hnljA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Taehee Yoo , "David S . Miller" , Greg Kroah-Hartman Subject: [PATCH 4.14 22/78] net: core: reduce recursion limit value Date: Mon, 29 Jun 2020 11:37:10 -0400 Message-Id: <20200629153806.2494953-23-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629153806.2494953-1-sashal@kernel.org> References: <20200629153806.2494953-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.14.186-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.14.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.14.186-rc1 X-KernelTest-Deadline: 2020-07-01T15:38+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Taehee Yoo [ Upstream commit fb7861d14c8d7edac65b2fcb6e8031cb138457b2 ] In the current code, ->ndo_start_xmit() can be executed recursively only 10 times because of stack memory. But, in the case of the vxlan, 10 recursion limit value results in a stack overflow. In the current code, the nested interface is limited by 8 depth. There is no critical reason that the recursion limitation value should be 10. So, it would be good to be the same value with the limitation value of nesting interface depth. Test commands: ip link add vxlan10 type vxlan vni 10 dstport 4789 srcport 4789 4789 ip link set vxlan10 up ip a a 192.168.10.1/24 dev vxlan10 ip n a 192.168.10.2 dev vxlan10 lladdr fc:22:33:44:55:66 nud permanent for i in {9..0} do let A=$i+1 ip link add vxlan$i type vxlan vni $i dstport 4789 srcport 4789 4789 ip link set vxlan$i up ip a a 192.168.$i.1/24 dev vxlan$i ip n a 192.168.$i.2 dev vxlan$i lladdr fc:22:33:44:55:66 nud permanent bridge fdb add fc:22:33:44:55:66 dev vxlan$A dst 192.168.$i.2 self done hping3 192.168.10.2 -2 -d 60000 Splat looks like: [ 103.814237][ T1127] ============================================================================= [ 103.871955][ T1127] BUG kmalloc-2k (Tainted: G B ): Padding overwritten. 0x00000000897a2e4f-0x000 [ 103.873187][ T1127] ----------------------------------------------------------------------------- [ 103.873187][ T1127] [ 103.874252][ T1127] INFO: Slab 0x000000005cccc724 objects=5 used=5 fp=0x0000000000000000 flags=0x10000000001020 [ 103.881323][ T1127] CPU: 3 PID: 1127 Comm: hping3 Tainted: G B 5.7.0+ #575 [ 103.882131][ T1127] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 103.883006][ T1127] Call Trace: [ 103.883324][ T1127] dump_stack+0x96/0xdb [ 103.883716][ T1127] slab_err+0xad/0xd0 [ 103.884106][ T1127] ? _raw_spin_unlock+0x1f/0x30 [ 103.884620][ T1127] ? get_partial_node.isra.78+0x140/0x360 [ 103.885214][ T1127] slab_pad_check.part.53+0xf7/0x160 [ 103.885769][ T1127] ? pskb_expand_head+0x110/0xe10 [ 103.886316][ T1127] check_slab+0x97/0xb0 [ 103.886763][ T1127] alloc_debug_processing+0x84/0x1a0 [ 103.887308][ T1127] ___slab_alloc+0x5a5/0x630 [ 103.887765][ T1127] ? pskb_expand_head+0x110/0xe10 [ 103.888265][ T1127] ? lock_downgrade+0x730/0x730 [ 103.888762][ T1127] ? pskb_expand_head+0x110/0xe10 [ 103.889244][ T1127] ? __slab_alloc+0x3e/0x80 [ 103.889675][ T1127] __slab_alloc+0x3e/0x80 [ 103.890108][ T1127] __kmalloc_node_track_caller+0xc7/0x420 [ ... ] Fixes: 11a766ce915f ("net: Increase xmit RECURSION_LIMIT to 10.") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/netdevice.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 31fc54757bf2e..3512c337a4a6b 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2449,7 +2449,7 @@ void synchronize_net(void); int init_dummy_netdev(struct net_device *dev); DECLARE_PER_CPU(int, xmit_recursion); -#define XMIT_RECURSION_LIMIT 10 +#define XMIT_RECURSION_LIMIT 8 static inline int dev_recursion_level(void) { -- 2.25.1