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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 41538C004C9 for ; Tue, 7 May 2019 05:55:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11A2A2054F for ; Tue, 7 May 2019 05:55:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557208508; bh=4ivpgEHAd/I1nF4RAywRQNrnfof+eIb6bU1DhLaTCd0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Sgx1bg/5uaQvdWvYwGK2H7DTl7vQzUGVtXILYcBk1Jwk/FqHcK84IgHwBolS8OJLV Ir/bJlxwUMYYbvPdL0g9yoe+o1v2eT6vRsoCf4xy7A9ZTbbGVunpIU4Tn6qvcpRK44 NtelR8FBnXFWy5M8erWA77+tvGUPH2kvYwjIApvs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728612AbfEGFiT (ORCPT ); Tue, 7 May 2019 01:38:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:58080 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728597AbfEGFiS (ORCPT ); Tue, 7 May 2019 01:38:18 -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 B998A20B7C; Tue, 7 May 2019 05:38:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557207497; bh=4ivpgEHAd/I1nF4RAywRQNrnfof+eIb6bU1DhLaTCd0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vcc9X2C+QX9jKQQMcrmMAwNg8lUJtKUgPBDfLjPixpHdX60tHHfPUDsMdiau+kxGv DXzY4LfuaxgT2WPpNDLEvo2k9KFJlBeLtK67XJCNPNqFJyPKuVGc+kVioaar8/k77q iiFVCaxWvrbEdvMKR/eFo67YdGyQA+dSXYzfkojY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jakub Kicinski , Dirk van der Merwe , Eric Dumazet , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 78/81] net: strparser: partially revert "strparser: Call skb_unclone conditionally" Date: Tue, 7 May 2019 01:35:49 -0400 Message-Id: <20190507053554.30848-78-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190507053554.30848-1-sashal@kernel.org> References: <20190507053554.30848-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jakub Kicinski [ Upstream commit 4a9c2e3746e6151fd5d077259d79ce9ca86d47d7 ] This reverts the first part of commit 4e485d06bb8c ("strparser: Call skb_unclone conditionally"). To build a message with multiple fragments we need our own root of frag_list. We can't simply use the frag_list of orig_skb, because it will lead to linking all orig_skbs together creating very long frag chains, and causing stack overflow on kfree_skb() (which is called recursively on the frag_lists). BUG: stack guard page was hit at 00000000d40fad41 (stack is 0000000029dde9f4..000000008cce03d5) kernel stack overflow (double-fault): 0000 [#1] PREEMPT SMP RIP: 0010:free_one_page+0x2b/0x490 Call Trace: __free_pages_ok+0x143/0x2c0 skb_release_data+0x8e/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 [...] skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 ? skb_release_data+0xad/0x140 kfree_skb+0x32/0xb0 skb_release_data+0xad/0x140 __kfree_skb+0xe/0x20 tcp_disconnect+0xd6/0x4d0 tcp_close+0xf4/0x430 ? tcp_check_oom+0xf0/0xf0 tls_sk_proto_close+0xe4/0x1e0 [tls] inet_release+0x36/0x60 __sock_release+0x37/0xa0 sock_close+0x11/0x20 __fput+0xa2/0x1d0 task_work_run+0x89/0xb0 exit_to_usermode_loop+0x9a/0xa0 do_syscall_64+0xc0/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Let's leave the second unclone conditional, as I'm not entirely sure what is its purpose :) Fixes: 4e485d06bb8c ("strparser: Call skb_unclone conditionally") Signed-off-by: Jakub Kicinski Reviewed-by: Dirk van der Merwe Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/strparser/strparser.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c index da1a676860ca..0f4e42792878 100644 --- a/net/strparser/strparser.c +++ b/net/strparser/strparser.c @@ -140,13 +140,11 @@ static int __strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb, /* We are going to append to the frags_list of head. * Need to unshare the frag_list. */ - if (skb_has_frag_list(head)) { - err = skb_unclone(head, GFP_ATOMIC); - if (err) { - STRP_STATS_INCR(strp->stats.mem_fail); - desc->error = err; - return 0; - } + err = skb_unclone(head, GFP_ATOMIC); + if (err) { + STRP_STATS_INCR(strp->stats.mem_fail); + desc->error = err; + return 0; } if (unlikely(skb_shinfo(head)->frag_list)) { -- 2.20.1