From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominick Grift Subject: Re: Suspicious RCU usage in bridge with Linux v4.0-9362-g1fc149933fd4 Date: Mon, 4 May 2015 15:39:44 +0200 Message-ID: <20150504133943.GA17043@x131e> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="8t9RHnE3ZwKMSgU+" To: netdev@vger.kernel.org Return-path: Received: from mail-wi0-f178.google.com ([209.85.212.178]:35251 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752116AbbEDNjr (ORCPT ); Mon, 4 May 2015 09:39:47 -0400 Received: by widdi4 with SMTP id di4so121888544wid.0 for ; Mon, 04 May 2015 06:39:46 -0700 (PDT) Received: from x131e (217-19-24-195.dsl.cambrium.nl. [217.19.24.195]) by mx.google.com with ESMTPSA id gy8sm11275391wib.13.2015.05.04.06.39.45 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 May 2015 06:39:45 -0700 (PDT) Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: --8t9RHnE3ZwKMSgU+ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Apr 23, 2015 at 01:07:45PM -0400, Josh Boyer wrote: > Hi All, >=20 > We've had a user report the following backtrace from the bridge module > with a recent Linus' tree. Has anything like this been reported yet? > If you have any questions on setup, the user is CC'd. >=20 > josh >=20 > [ 29.382235] br0: port 1(tap0) entered forwarding state >=20 > [ 29.382286] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > [ 29.382315] [ INFO: suspicious RCU usage. ] > [ 29.382344] 4.1.0-0.rc0.git11.1.fc23.x86_64 #1 Not tainted > [ 29.382380] ------------------------------- > [ 29.382409] net/bridge/br_private.h:626 suspicious > rcu_dereference_check() usage! With 4.1.0-0.rc1.git1.1.fc23.x86_64 the situation seems to have slightly ch= anged: May 04 14:51:34 d30 kernel: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D May 04 14:51:34 d30 kernel: [ INFO: suspicious RCU usage. ] May 04 14:51:34 d30 kernel: 4.1.0-0.rc1.git1.1.fc23.x86_64 #1 Not tainted May 04 14:51:34 d30 kernel: ------------------------------- May 04 14:51:34 d30 kernel: net/bridge/br_private.h:626 suspicious rcu_dere= ference_check() usage! May 04 14:51:34 d30 kernel: May 04 14:51:34 d30 kernel: May 04 14:51:34 d30 kernel: 3 locks held by qemu-system-x86/1133: May 04 14:51:34 d30 kernel: #0: (&vcpu->mutex){+.+.+.}, at: [] vcpu_load+0x26/0x70 [kvm] May 04 14:51:34 d30 kernel: #1: (((&p->forward_delay_timer))){+.-...}, at= : [] call_timer_fn+0x5/0x4f0 May 04 14:51:34 d30 kernel: #2: (&(&br->lock)->rlock){+.-...}, at: [] br_forward_delay_timer_expired+0x31/0x140 [bridge] May 04 14:51:34 d30 kernel: May 04 14:51:34 d30 kernel: CPU: 6 PID: 1133 Comm: qemu-system-x86 Not tain= ted 4.1.0-0.rc1.git1.1.fc23.x86_64 #1 May 04 14:51:34 d30 kernel: Hardware name: LENOVO 422916G/LENOVO, BIOS A1KT= 53AUS 04/07/2015 May 04 14:51:34 d30 kernel: 0000000000000000 000000000dce176d ffff880c65e0= 3c48 ffffffff81893b45 May 04 14:51:34 d30 kernel: 0000000000000000 ffff880c5e869a60 ffff880c65e0= 3c78 ffffffff8110bb17 May 04 14:51:34 d30 kernel: ffff880c56f6f700 ffff880c61a35c58 ffff880c5c14= d000 ffff88065b470ac0 May 04 14:51:34 d30 kernel: Call Trace: May 04 14:51:34 d30 kernel: [] dump_stack+0x4c/0x= 65 May 04 14:51:34 d30 kernel: [] lockdep_rcu_suspicious+0x= e7/0x120 May 04 14:51:34 d30 kernel: [] br_fill_ifinfo+0x4a9/0x6a= 0 [bridge] May 04 14:51:34 d30 kernel: [] br_ifinfo_notify+0x11b/0x= 4b0 [bridge] May 04 14:51:34 d30 kernel: [] ? br_hold_timer_expired+0= x70/0x70 [bridge] May 04 14:51:34 d30 kernel: [] br_forward_delay_timer_ex= pired+0x58/0x140 [bridge] May 04 14:51:34 d30 kernel: [] ? br_hold_timer_expired+0= x70/0x70 [bridge] May 04 14:51:34 d30 kernel: [] call_timer_fn+0xc3/0x4f0 May 04 14:51:34 d30 kernel: [] ? call_timer_fn+0x5/0x4f0 May 04 14:51:34 d30 kernel: [] ? _raw_spin_unlock_irq+0x= 30/0x50 May 04 14:51:34 d30 kernel: [] ? br_hold_timer_expired+0= x70/0x70 [bridge] May 04 14:51:34 d30 kernel: [] run_timer_softirq+0x244/0= x490 May 04 14:51:34 d30 kernel: [] ? __do_softirq+0xb7/0x670 May 04 14:51:34 d30 kernel: [] __do_softirq+0xec/0x670 May 04 14:51:34 d30 kernel: [] ? vmx_invpcid_supported+0= x30/0x30 [kvm_intel] May 04 14:51:34 d30 kernel: [] irq_exit+0x145/0x150 May 04 14:51:34 d30 kernel: [] smp_apic_timer_interrupt+= 0x46/0x60 May 04 14:51:34 d30 kernel: [] ? uv_bau_message_intr1+0x= 80/0x80 May 04 14:51:34 d30 kernel: [] apic_timer_interrupt+0x73= /0x80 May 04 14:51:34 d30 kernel: [] ? vmx_vcpu_run+0x8= 71/0x8a0 [kvm_intel] May 04 14:51:34 d30 kernel: [] ? uv_bau_message_intr1+0x= 80/0x80 May 04 14:51:34 d30 kernel: [] ? vmx_handle_external_int= r+0x6f/0x70 [kvm_intel] May 04 14:51:34 d30 kernel: [] ? kvm_arch_vcpu_ioctl_run= +0x71f/0x1ba0 [kvm] May 04 14:51:34 d30 kernel: [] ? kvm_arch_vcpu_ioctl_run= +0x76f/0x1ba0 [kvm] May 04 14:51:34 d30 kernel: [] ? trace_hardirqs_on+0xd/0= x10 May 04 14:51:34 d30 kernel: [] ? vcpu_load+0x26/0x70 [kv= m] May 04 14:51:34 d30 kernel: [] ? kvm_arch_vcpu_load+0x58= /0x210 [kvm] May 04 14:51:34 d30 kernel: [] kvm_vcpu_ioctl+0x383/0x7e= 0 [kvm] May 04 14:51:34 d30 kernel: [] ? native_sched_clock+0x2d= /0xa0 May 04 14:51:34 d30 kernel: [] ? creds_are_invalid.part.= 1+0x16/0x50 May 04 14:51:34 d30 kernel: [] ? creds_are_invalid+0x21/= 0x30 May 04 14:51:34 d30 kernel: [] ? inode_has_perm.isra.48+= 0x2a/0xa0 May 04 14:51:34 d30 kernel: [] do_vfs_ioctl+0x2e8/0x530 May 04 14:51:34 d30 kernel: [] SyS_ioctl+0x81/0xa0 May 04 14:51:34 d30 kernel: [] system_call_fastpath+0x12= /0x76 May 04 14:51:34 d30 kernel: br0: port 1(tap0) entered forwarding state May 04 14:51:34 d30 kernel: br0: port 3(tap2) entered forwarding state May 04 14:51:34 d30 kernel: br0: port 4(tap3) entered forwarding state=20 --=20 02DFF788 4D30 903A 1CF3 B756 FB48 1514 3148 83A2 02DF F788 http://keys.gnupg.net/pks/lookup?op=3Dvindex&search=3D0x314883A202DFF788 Dominick Grift --8t9RHnE3ZwKMSgU+ Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQGcBAEBCgAGBQJVR3aZAAoJENAR6kfG5xmcR/IMALh3GAUtmTQkltKHo6FNIGdJ FbGZL8ELedSOYmLa8lJrzSZhxouCg6f5yXNLOXAWgt8x06MRzWsUkAJxNNKinWpH 2B/Cggy5hZVkY89Dkyam0OTeu21WR4Z58JWxyYkt2G3RplndEynXO6IDVMp8bkcQ btpRxShZdV+SMrPoDHvxdH/OOii0jbLNv6oZl5TGAIpTVyOYSGx5VbVye2zUL/yD ERctuIWwfJShmQ52Gfa9cAxzoGHNEiXWNZGJd7legwDJh8LfmHJ+B76BoccrKUKI 3FePQwSHQQaNodONmIH4/B/p/FHbiJFXcaFwpiIip5zJDH3lV/eEtKjALoA2incE bDcRuGCRbSJW0UifbkpZOORdPJsuJe70nhtxAHJ+HEXUlXqnINd0EVCRvoEvd+jB 02T/OBtwIj/ojb3mbvCGICcFfKEzSwALOHu5agSF7PmBbl66VqtZUmjrEXBD2paI ab97HmPSdRwyab7fNclV2fETewG7fz+wDqWSR7miAA== =FkYA -----END PGP SIGNATURE----- --8t9RHnE3ZwKMSgU+--