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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 BEE6AC71122 for ; Sun, 14 Oct 2018 15:32:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9273420876 for ; Sun, 14 Oct 2018 15:32:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9273420876 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728612AbeJNXNs (ORCPT ); Sun, 14 Oct 2018 19:13:48 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36340 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728201AbeJNXMF (ORCPT ); Sun, 14 Oct 2018 19:12:05 -0400 Received: from [2a02:8011:400e:2:cbab:f00:c93f:614] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1gBiLr-0004cH-G6; Sun, 14 Oct 2018 16:30:43 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gBiLX-0000VZ-6f; Sun, 14 Oct 2018 16:30:23 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Gerrit Renker" , "syzbot" , dccp@vger.kernel.org, "Eric Dumazet" , "David S. Miller" Date: Sun, 14 Oct 2018 16:25:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 257/366] dccp: fix tasklet usage In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:cbab:f00:c93f:614 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit a8d7aa17bbc970971ccdf71988ea19230ab368b1 upstream. syzbot reported a crash in tasklet_action_common() caused by dccp. dccp needs to make sure socket wont disappear before tasklet handler has completed. This patch takes a reference on the socket when arming the tasklet, and moves the sock_put() from dccp_write_xmit_timer() to dccp_write_xmitlet() kernel BUG at kernel/softirq.c:514! invalid opcode: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 17 Comm: ksoftirqd/1 Not tainted 4.17.0-rc3+ #30 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:tasklet_action_common.isra.19+0x6db/0x700 kernel/softirq.c:515 RSP: 0018:ffff8801d9b3faf8 EFLAGS: 00010246 dccp_close: ABORT with 65423 bytes unread RAX: 1ffff1003b367f6b RBX: ffff8801daf1f3f0 RCX: 0000000000000000 RDX: ffff8801cf895498 RSI: 0000000000000004 RDI: 0000000000000000 RBP: ffff8801d9b3fc40 R08: ffffed0039f12a95 R09: ffffed0039f12a94 dccp_close: ABORT with 65423 bytes unread R10: ffffed0039f12a94 R11: ffff8801cf8954a3 R12: 0000000000000000 R13: ffff8801d9b3fc18 R14: dffffc0000000000 R15: ffff8801cf895490 FS: 0000000000000000(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2bc28000 CR3: 00000001a08a9000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tasklet_action+0x1d/0x20 kernel/softirq.c:533 __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285 dccp_close: ABORT with 65423 bytes unread run_ksoftirqd+0x86/0x100 kernel/softirq.c:646 smpboot_thread_fn+0x417/0x870 kernel/smpboot.c:164 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Code: 48 8b 85 e8 fe ff ff 48 8b 95 f0 fe ff ff e9 94 fb ff ff 48 89 95 f0 fe ff ff e8 81 53 6e 00 48 8b 95 f0 fe ff ff e9 62 fb ff ff <0f> 0b 48 89 cf 48 89 8d e8 fe ff ff e8 64 53 6e 00 48 8b 8d e8 RIP: tasklet_action_common.isra.19+0x6db/0x700 kernel/softirq.c:515 RSP: ffff8801d9b3faf8 Fixes: dc841e30eaea ("dccp: Extend CCID packet dequeueing interface") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Gerrit Renker Cc: dccp@vger.kernel.org Signed-off-by: David S. Miller [bwh: Backported to 3.16: Timer parameter is still an unsigned long] Signed-off-by: Ben Hutchings --- net/dccp/ccids/ccid2.c | 14 ++++++++++++-- net/dccp/timer.c | 2 +- 2 files changed, 13 insertions(+), 3 deletions(-) --- a/net/dccp/ccids/ccid2.c +++ b/net/dccp/ccids/ccid2.c @@ -126,6 +126,16 @@ static void ccid2_change_l_seq_window(st DCCPF_SEQ_WMAX)); } +static void dccp_tasklet_schedule(struct sock *sk) +{ + struct tasklet_struct *t = &dccp_sk(sk)->dccps_xmitlet; + + if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { + sock_hold(sk); + __tasklet_schedule(t); + } +} + static void ccid2_hc_tx_rto_expire(unsigned long data) { struct sock *sk = (struct sock *)data; @@ -166,7 +176,7 @@ static void ccid2_hc_tx_rto_expire(unsig /* if we were blocked before, we may now send cwnd=1 packet */ if (sender_was_blocked) - tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); + dccp_tasklet_schedule(sk); /* restart backed-off timer */ sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); out: @@ -706,7 +716,7 @@ static void ccid2_hc_tx_packet_recv(stru done: /* check if incoming Acks allow pending packets to be sent */ if (sender_was_blocked && !ccid2_cwnd_network_limited(hc)) - tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); + dccp_tasklet_schedule(sk); dccp_ackvec_parsed_cleanup(&hc->tx_av_chunks); } --- a/net/dccp/timer.c +++ b/net/dccp/timer.c @@ -252,12 +252,12 @@ static void dccp_write_xmitlet(unsigned else dccp_write_xmit(sk); bh_unlock_sock(sk); + sock_put(sk); } static void dccp_write_xmit_timer(unsigned long data) { dccp_write_xmitlet(data); - sock_put((struct sock *)data); } void dccp_init_xmit_timers(struct sock *sk)