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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 92534C432C0 for ; Tue, 26 Nov 2019 08:40:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 71329206BF for ; Tue, 26 Nov 2019 08:40:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727154AbfKZIkr (ORCPT ); Tue, 26 Nov 2019 03:40:47 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:41161 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725862AbfKZIkr (ORCPT ); Tue, 26 Nov 2019 03:40:47 -0500 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1iZWOg-00046e-Go; Tue, 26 Nov 2019 09:40:34 +0100 Date: Tue, 26 Nov 2019 09:40:34 +0100 From: Sebastian Andrzej Siewior To: Joerg Vehlow , Steven Rostedt Cc: linux-kernel@vger.kernel.org, trix@redhat.com, Joerg Vehlow , Thomas Gleixner , Daniel Wagner , Tom Zanussi , Clark Williams , stable-rt@vger.kernel.org Subject: Re: [PATCH RT v3] net/xfrm/input: Protect queue with lock Message-ID: <20191126084034.g2fgdocw7qok3xcd@linutronix.de> References: <20191126071335.34661-1-lkml@jv-coder.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191126071335.34661-1-lkml@jv-coder.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-11-26 08:13:35 [+0100], Joerg Vehlow wrote: > From: Joerg Vehlow > > During the skb_queue_splice_init the tasklet could have been preempted > and_skb_queue_tail called, which led to an inconsistent queue. > > Affected are all rt kernels up to 5.0.19-rt11 (due to bh rework). > > It was found using ipsec stress tests (e.g. ipcomp) in ltp suite. > Running them in a continous loop triggered the bug in qemu within 5-10 retries. Acked-by: Sebastian Andrzej Siewior > [ 139.717259] BUG: unable to handle kernel NULL pointer dereference at 0000000000000518 > [ 139.717260] PGD 0 P4D 0 > [ 139.717262] Oops: 0000 [#1] PREEMPT SMP PTI > [ 139.717273] CPU: 2 PID: 11987 Comm: netstress Not tainted 4.19.59-rt24-preemt-rt #1 > [ 139.717274] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 > [ 139.717306] RIP: 0010:xfrm_trans_reinject+0x97/0xd0 > [ 139.717307] Code: 42 eb 45 83 6d b0 01 31 f6 48 8b 42 08 48 c7 42 08 00 00 00 00 48 8b 0a 48 c7 02 00 00 00 00 48 89 41 08 48 89 08 48 8b 42 10 <48> 8b b8 18 05 00 00 48 8b 42 40 e8 d9 e1 4b 00 48 8b 55 a0 48 39 > [ 139.717307] RSP: 0018:ffffc900007b37e8 EFLAGS: 00010246 > [ 139.717308] RAX: 0000000000000000 RBX: ffffc900007b37e8 RCX: ffff88807db206a8 > [ 139.717309] RDX: ffff88807db206a8 RSI: 0000000000000000 RDI: 0000000000000000 > [ 139.717309] RBP: ffffc900007b3848 R08: 0000000000000001 R09: ffffc900007b35c8 > [ 139.717309] R10: ffffea0001dcfc00 R11: 00000000000890c4 R12: ffff88807db20680 > [ 139.717310] R13: 00000000000f4240 R14: 0000000000000000 R15: 0000000000000000 > [ 139.717310] FS: 00007f4643034700(0000) GS:ffff88807db00000(0000) knlGS:0000000000000000 > [ 139.717311] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 139.717337] CR2: 0000000000000518 CR3: 00000000769c6000 CR4: 00000000000006e0 > [ 139.717350] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 139.717350] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 139.717350] Call Trace: > [ 139.717387] tasklet_action_common.isra.18+0x6d/0xd0 > [ 139.717388] tasklet_action+0x1d/0x20 > [ 139.717389] do_current_softirqs+0x196/0x360 > [ 139.717390] __local_bh_enable+0x51/0x60 > [ 139.717397] ip_finish_output2+0x18b/0x3f0 > [ 139.717408] ? task_rq_lock+0x53/0xe0 > [ 139.717415] ip_finish_output+0xbe/0x1b0 > [ 139.717416] ip_output+0x72/0x100 > [ 139.717422] ? ipcomp_output+0x5e/0x280 > [ 139.717424] xfrm_output_resume+0x4b5/0x540 > [ 139.717436] ? refcount_dec_and_test_checked+0x11/0x20 > [ 139.717443] ? kfree_skbmem+0x33/0x80 > [ 139.717444] xfrm_output+0xd7/0x110 > [ 139.717451] xfrm4_output_finish+0x2b/0x30 > [ 139.717452] __xfrm4_output+0x3a/0x50 > [ 139.717453] xfrm4_output+0x40/0xe0 > [ 139.717454] ? xfrm_dst_check+0x174/0x250 > [ 139.717455] ? xfrm4_output+0x40/0xe0 > [ 139.717456] ? xfrm_dst_check+0x174/0x250 > [ 139.717457] ip_local_out+0x3b/0x50 > [ 139.717458] __ip_queue_xmit+0x16b/0x420 > [ 139.717464] ip_queue_xmit+0x10/0x20 > [ 139.717466] __tcp_transmit_skb+0x566/0xad0 > [ 139.717467] tcp_write_xmit+0x3a4/0x1050 > [ 139.717468] __tcp_push_pending_frames+0x35/0xe0 > [ 139.717469] tcp_push+0xdb/0x100 > [ 139.717469] tcp_sendmsg_locked+0x491/0xd70 > [ 139.717470] tcp_sendmsg+0x2c/0x50 > [ 139.717476] inet_sendmsg+0x3e/0xf0 > [ 139.717483] sock_sendmsg+0x3e/0x50 > [ 139.717484] __sys_sendto+0x114/0x1a0 > [ 139.717491] ? __rt_mutex_unlock+0xe/0x10 > [ 139.717492] ? _mutex_unlock+0xe/0x10 > [ 139.717500] ? ksys_write+0xc5/0xe0 > [ 139.717501] __x64_sys_sendto+0x28/0x30 > [ 139.717503] do_syscall_64+0x4d/0x110 > [ 139.717504] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Signed-off-by: Joerg Vehlow > --- > net/xfrm/xfrm_input.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c > index 790b514f86b6..4c4e669fcd16 100644 > --- a/net/xfrm/xfrm_input.c > +++ b/net/xfrm/xfrm_input.c > @@ -512,12 +512,15 @@ EXPORT_SYMBOL(xfrm_input_resume); > > static void xfrm_trans_reinject(unsigned long data) > { > + unsigned long flags; > struct xfrm_trans_tasklet *trans = (void *)data; > struct sk_buff_head queue; > struct sk_buff *skb; > > __skb_queue_head_init(&queue); > + spin_lock_irqsave(&trans->queue.lock, flags); > skb_queue_splice_init(&trans->queue, &queue); > + spin_unlock_irqrestore(&trans->queue.lock, flags); > > while ((skb = __skb_dequeue(&queue))) > XFRM_TRANS_SKB_CB(skb)->finish(dev_net(skb->dev), NULL, skb); > @@ -535,7 +538,7 @@ int xfrm_trans_queue(struct sk_buff *skb, > return -ENOBUFS; > > XFRM_TRANS_SKB_CB(skb)->finish = finish; > - __skb_queue_tail(&trans->queue, skb); > + skb_queue_tail(&trans->queue, skb); > tasklet_schedule(&trans->tasklet); > return 0; > } > @@ -560,7 +563,7 @@ void __init xfrm_input_init(void) > struct xfrm_trans_tasklet *trans; > > trans = &per_cpu(xfrm_trans_tasklet, i); > - __skb_queue_head_init(&trans->queue); > + skb_queue_head_init(&trans->queue); > tasklet_init(&trans->tasklet, xfrm_trans_reinject, > (unsigned long)trans); > } > -- > 2.20.1 > Sebastian