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=-10.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7BC68C433B4 for ; Tue, 18 May 2021 14:20:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62379611CE for ; Tue, 18 May 2021 14:20:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343836AbhEROWP (ORCPT ); Tue, 18 May 2021 10:22:15 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:17940 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244914AbhEROWP (ORCPT ); Tue, 18 May 2021 10:22:15 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1621347657; h=In-Reply-To: Content-Type: MIME-Version: References: Message-ID: Subject: Cc: To: From: Date: Sender; bh=PxOKGgGqk8G3t3tnFzMoFUTyloOwIaVdsgo/tN5fkV8=; b=Y7y1ZwkovKyZvwF/tZhtyYs98PY+mTBoQs+sSjq+sqZxVRYouXcqBzMr7F9d6cd1VecUas0r LBh+r/mECOMUQ1AZ22x3gg6Cf+VC5M8L8R/E7+X8ggG6wEgTz482Y8pHxbAlx4Xsr2IjJRDm NVZF0+atxC8Frx4KjGOTbMLAm0Q= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyJiZjI2MiIsICJuZXRkZXZAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-west-2.postgun.com with SMTP id 60a3cd3b7b9a7a2b6c276bfe (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Tue, 18 May 2021 14:20:43 GMT Sender: kapandey=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 90302C43144; Tue, 18 May 2021 14:20:43 +0000 (UTC) Received: from kapandey-linux.qualcomm.com (unknown [202.46.22.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: kapandey) by smtp.codeaurora.org (Postfix) with ESMTPSA id 5EAE0C43460; Tue, 18 May 2021 14:20:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5EAE0C43460 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=kapandey@codeaurora.org Date: Tue, 18 May 2021 19:50:29 +0530 From: Kaustubh Pandey To: Paolo Abeni Cc: willemb@google.com, netdev@vger.kernel.org, eric.dumazet@gmail.com, sharathv@codeaurora.org, subashab@codeaurora.org Subject: Re: Panic in udp4_lib_lookup2 Message-ID: <20210518142023.GA16017@kapandey-linux.qualcomm.com> References: <20210513194810.GA25255@kapandey-linux.qualcomm.com> <4ba41620dbba70de6e3fed1356fc1910192cd074.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ba41620dbba70de6e3fed1356fc1910192cd074.camel@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, May 13, 2021 at 11:18:53PM +0200, Paolo Abeni wrote: > On Fri, 2021-05-14 at 01:18 +0530, Kaustubh Pandey wrote: > > On Thu, May 13, 2021 at 10:05:37AM +0200, Paolo Abeni wrote: > > > Hello, > > > > > > On Wed, 2021-05-12 at 23:51 +0530, kapandey@codeaurora.org wrote: > > > > We observed panic in udp_lib_lookup with below call trace: > > > > [136523.743271] (7) Call trace: > > > > [136523.743275] (7) udp4_lib_lookup2+0x88/0x1d8 > > > > [136523.743277] (7) __udp4_lib_lookup+0x168/0x194 > > > > [136523.743280] (7) udp4_lib_lookup+0x28/0x54 > > > > [136523.743285] (7) nf_sk_lookup_slow_v4+0x2b4/0x384 > > > > [136523.743289] (7) owner_mt+0xb8/0x248 > > > > [136523.743292] (7) ipt_do_table+0x28c/0x6a8 > > > > [136523.743295] (7) iptable_filter_hook+0x24/0x30 > > > > [136523.743299] (7) nf_hook_slow+0xa8/0x148 > > > > [136523.743303] (7) ip_local_deliver+0xa8/0x14c > > > > [136523.743305] (7) ip_rcv+0xe0/0x134 > > > > > > It would be helpful if you could provide a full, decoded, stack trace > > > and the relevant kernel version. > > > > > > > We suspect this might happen due to below sequence: > > > > > > Some email formatting made the "graph" very hard to read... > > > > > > > Time CPU X > > > > > > > > CPU Y > > > > t0 inet_release -> udp_lib_close -> > > > > sk_common_release -> udp_lib_unhash > > > > inet_diag_handler_cmd -> udp_diag_destroy -> __udp_diag_destroy -> > > > > udp_lib_rehash > > > > > > ... but it looks like udp_lib_close() is missing a > > > lock_sock()/release_sock() pair. Something alike: > > > --- > > > diff --git a/include/net/udp.h b/include/net/udp.h > > > index 360df454356c..06586b42db3f 100644 > > > --- a/include/net/udp.h > > > +++ b/include/net/udp.h > > > @@ -209,7 +209,9 @@ void udp_lib_rehash(struct sock *sk, u16 new_hash); > > > > > > static inline void udp_lib_close(struct sock *sk, long timeout) > > > { > > > + lock_sock(sk); > > > sk_common_release(sk); > > > + release_sock(sk); > > > } > > > > > > int udp_lib_get_port(struct sock *sk, unsigned short snum, > > > --- > > > > > > could u please give the above a spin in your testbed? > > > > > > Thanks! > > > > > > Paolo > > > > > > > > Hi Paolo, > > > > Pls find full backtrace: > > [136523.743141]Unable to handle kernel paging request at virtual address > > 00000c08ff000820 > > > > [136523.743147]Mem abort info: > > [136523.743150] ESR = 0x96000004 > > [136523.743154] EC = 0x25: DABT (current EL), IL = 32 bits > > [136523.743157] SET = 0, FnV = 0 > > [136523.743159] EA = 0, S1PTW = 0 > > [136523.743162]Data abort info: > > [136523.743164] ISV = 0, ISS = 0x00000004 > > [136523.743167] CM = 0, WnR = 0 > > [136523.743170][00000c08ff000820] address between user and kernel > > address ranges > > [136523.743174]Internal error: Oops: 96000004 [#1] PREEMPT SMP > > [136523.743218]pstate: a0c00005 (NzCv daif +PAN +UAO) > > > > [136523.743226]pc : udp4_lib_lookup2+0x88/0x1d8 > > [136523.743229]lr : __udp4_lib_lookup+0x168/0x194 > > > > [136523.743232]sp : ffffffc039a9b600 > > [136523.743234]x29: ffffffc039a9b610 x28: 0000000000000000 > > [136523.743237]x27: 0000000000000000 x26: ff000c08ff0007f0 > > [136523.743239]x25: ffffffe1e2319b40 x24: 0000000073737272 > > [136523.743242]x23: 0000000000003500 x22: 0000000000000000 > > [136523.743244]x21: 000000000000a622 x20: 000000000000001a > > [136523.743246]x19: 00000000ffffffff x18: ffffffc02b6d7098 > > [136523.743249]x17: 0000000000000000 x16: 0000000000000000 > > [136523.743251]x15: 0000000000000000 x14: 0000000000000000 > > [136523.743254]x13: 0000000000000000 x12: ffffff81d8e30000 > > [136523.743257]x11: 0000000000000fff x10: ff000c08ff0007f0 > > [136523.743259]x9 : ff000c08ff000808 x8 : 0000000000000000 > > [136523.743261]x7 : ffffff81d8e3e6a0 x6 : 0000000000000000 > > [136523.743263]x5 : 000000000000001a x4 : 000000000000a622 > > [136523.743266]x3 : 0000000000000000 x2 : 0000000000003500 > > [136523.743268]x1 : 0000000073737272 x0 : ffffffe1e2319b40 > > [136523.743271]Call trace: > > [136523.743275] udp4_lib_lookup2+0x88/0x1d8 > > [136523.743277] __udp4_lib_lookup+0x168/0x194 > > [136523.743280] udp4_lib_lookup+0x28/0x54 > > [136523.743285] nf_sk_lookup_slow_v4+0x2b4/0x384 > > [136523.743289] owner_mt+0xb8/0x248 > > [136523.743292] ipt_do_table+0x28c/0x6a8 > > [136523.743295] iptable_filter_hook+0x24/0x30 > > [136523.743299] nf_hook_slow+0xa8/0x148 > > [136523.743303] ip_local_deliver+0xa8/0x14c > > [136523.743305] ip_rcv+0xe0/0x134 > > [136523.743309] __netif_receive_skb_core+0x9d0/0xd74 > > [136523.743313] __netif_receive_skb+0x50/0x17c > > [136523.743316] netif_receive_skb_internal+0xa0/0xd8 > > [136523.743318] netif_receive_skb+0xec/0x1e4 > > > > Kernel version used is 5.4 > > > > Derived from your suggestion I think below change might be more suited > > here: > > diff --git a/net/core/sock.c b/net/core/sock.c > > index f87c9f7..a5dd0e5 100644 > > --- a/net/core/sock.c > > +++ b/net/core/sock.c > > @@ -3210,7 +3210,9 @@ void sk_common_release(struct sock *sk) > > * A. Remove from hash tables. > > */ > > + lock_sock(sk); > > sk->sk_prot->unhash(sk); > > + release_sock(sk); > > The above will cause deadlock on protocol rightfully calling > sk_common_release under the socket lock (e.g. sctp). > > Could you please test the change I suggested in your testbed? > > Thanks > > Paolo > Hi Paolo, I picked up your change and with that it get stuck in udp_destroy_sock trying to do lock_sock_fast. Can you guide for next steps here? Thanks, KP