Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753584Ab3F2HUe (ORCPT ); Sat, 29 Jun 2013 03:20:34 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:45272 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752657Ab3F2HUc (ORCPT ); Sat, 29 Jun 2013 03:20:32 -0400 Message-ID: <1372490428.3301.300.camel@edumazet-glaptop> Subject: Re: kernel panic in skb_copy_bits From: Eric Dumazet To: Joe Jin Cc: Frank Blaschka , "David S. Miller" , "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" , "zheng.x.li@oracle.com" , Xen Devel , Ian Campbell , Jan Beulich , Stefano Stabellini Date: Sat, 29 Jun 2013 00:20:28 -0700 In-Reply-To: <51CE1E19.3020108@oracle.com> References: <51CBAA48.3080802@oracle.com> <1372311118.3301.214.camel@edumazet-glaptop> <51CD0E67.4000008@oracle.com> <1372402340.3301.229.camel@edumazet-glaptop> <1372412262.3301.251.camel@edumazet-glaptop> <51CE1E19.3020108@oracle.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2292 Lines: 42 On Sat, 2013-06-29 at 07:36 +0800, Joe Jin wrote: > Hi Eric, > > The patch not fix the issue and panic as same as early I posted: > > BUG: unable to handle kernel paging request at ffff88006d9e8d48 > > IP: [] memcpy+0xb/0x120 > > PGD 1798067 PUD 1fd2067 PMD 213f067 PTE 0 > > Oops: 0000 [#1] SMP > > CPU 7 > > Modules linked in: dm_nfs tun nfs fscache auth_rpcgss nfs_acl xen_blkback xen_netback xen_gntdev xen_evtchn lockd sunrpc bridge stp llc bonding be2iscsi iscsi_boot_sysfs ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp bnx2i cnic uio ipv6 cxgb3i libcxgbi cxgb3 mdio dm_round_robin dm_multipath libiscsi_tcp libiscsi scsi_transport_iscsi xenfs xen_privcmd video sbs sbshc acpi_memhotplug acpi_ipmi ipmi_msghandler parport_pc lp parport ixgbe dca sr_mod cdrom bnx2 radeon ttm drm_kms_helper drm snd_seq_dummy i2c_algo_bit i2c_core snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss serio_raw snd_pcm snd_timer snd soundcore snd_page_alloc iTCO_wdt pcspkr iTCO_vendor_support pata_acpi dcdbas i5k_amb ata_generic hwmon floppy ghes i5000_edac edac_core hed dm_snapshot dm_zero dm_mirror dm_region_hash dm_log dm_mod usb_storage lpfc scsi_transport_fc scsi_tgt ata_piix sg shpchp mptsas mptscsih mptbase scsi_transport_sas sd_mod crc_t10dif ext3! > jbd mbcac > he > > > > > > Pid: 0, comm: swapper Tainted: G W 2.6.39-300.32.1.el5uek #1 Dell Inc. PowerEdge 2950/0DP246 By the way my patch was for current kernels, not for 2.6.39 For instance, I was not able to reproduce the crash with 3.3 RCU in neighbour code was added in 2.6.37, but it looks like this code is a bit fragile because all the kfree_skb() are done while neighbour locks are held. So if a skb destructor triggers a new call to neighbour code, I presume some bad things can happen. LOCKDEP could eventually help to detect this. You could try to replace these kfree_skb() calls to dev_kfree_skb_irq() just in case. (Do not forget the __skb_queue_purge() ones) Try a LOCKDEP build as well. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/