From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754545AbbAFXzr (ORCPT ); Tue, 6 Jan 2015 18:55:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42964 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751667AbbAFXzp (ORCPT ); Tue, 6 Jan 2015 18:55:45 -0500 Message-ID: <1420588530.3541.116.camel@redhat.com> Subject: Re: [PATCH v8 34/50] vhost/net: virtio 1.0 byte swap From: Alex Williamson To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, David Miller , cornelia.huck@de.ibm.com, rusty@au1.ibm.com, nab@linux-iscsi.org, pbonzini@redhat.com, thuth@linux.vnet.ibm.com, dahi@linux.vnet.ibm.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Date: Tue, 06 Jan 2015 16:55:30 -0700 In-Reply-To: <1417449619-24896-35-git-send-email-mst@redhat.com> References: <1417449619-24896-1-git-send-email-mst@redhat.com> <1417449619-24896-35-git-send-email-mst@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-12-01 at 18:05 +0200, Michael S. Tsirkin wrote: > I had to add an explicit tag to suppress compiler warning: > gcc isn't smart enough to notice that > len is always initialized since function is called with size > 0. I'm getting a panic inside a guest when this change is applied on the host. I identified this patch via bisect and confirmed by reverting it from v3.19-rc2. Guest is centos6. Thanks, Alex commit 8b38694a2dc8b18374310df50174f1e4376d6824 Author: Michael S. Tsirkin Date: Fri Oct 24 14:19:48 2014 +0300 vhost/net: virtio 1.0 byte swap I had to add an explicit tag to suppress compiler warning: gcc isn't smart enough to notice that len is always initialized since function is called with size > 0. Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck XML chunk:
Panic log: <1>BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 <1>IP: [] virtnet_poll+0x4f9/0x910 [virtio_net] <4>PGD 1aa2f4067 PUD 1aa2f5067 PMD 0 <4>Oops: 0000 [#1] SMP <4>last sysfs file: /sys/devices/pci0000:00/0000:00:03.0/virtio0/net/eth9/ifindex <4>CPU 0 <4>Modules linked in: 8021q garp stp llc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 uinput microcode snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore snd_page_alloc igbvf nvidia(P)(U) i2c_core tg3 ptp pps_core virtio_balloon virtio_net virtio_console ext4 jbd2 mbcache virtio_blk virtio_pci virtio_ring virtio pata_acpi ata_generic ata_piix dm_mirror dm_region_hash dm_log dm_mod [last unloaded: speedstep_lib] <4> <4>Pid: 1374, comm: NetworkManager Tainted: P --------------- 2.6.32-431.23.3.el6.centos.plus.x86_64 #1 QEMU Standard PC (i440FX + PIIX, 1996) <4>RIP: 0010:[] [] virtnet_poll+0x4f9/0x910 [virtio_net] <4>RSP: 0018:ffff880028203e48 EFLAGS: 00010246 <4>RAX: ffff8801a3383d00 RBX: ffff8801a6aaf480 RCX: ffff8801aa20b6e0 <4>RDX: 00000000000000c0 RSI: ffff8801a3383c00 RDI: ffff8801a3383cc0 <4>RBP: ffff880028203ed8 R08: 000000000000009e R09: ffff8801aa1d800c <4>R10: 0000000000000218 R11: 0000000000000000 R12: ffff8801aa20b6e0 <4>R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 <4>FS: 00007febf114d800(0000) GS:ffff880028200000(0000) knlGS:0000000000000000 <4>CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>CR2: 0000000000000010 CR3: 00000001aa793000 CR4: 00000000000006f0 <4>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 <4>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 <4>Process NetworkManager (pid: 1374, threadinfo ffff8801a74ba000, task ffff8801a8d56040) <4>Stack: <4> ffff8801aa1d8000 000000000000009e ffff8801aa20b6e0 ffff8801aa20b718 <4> ffff8801aa20b780 ffff8801aa1d800c ffff8801a6aaf4b8 ffff8801aa20b020 <4> 0000000000000080 ffff8801aa20b708 0000000000000001 00001f5981a830c8 <4>Call Trace: <4> <4> [] net_rx_action+0x103/0x2f0 <4> [] __do_softirq+0xc1/0x1e0 <4> [] ? call_softirq+0x1c/0x30 <4> [] call_softirq+0x1c/0x30 <4> <4> [] ? do_softirq+0x65/0xa0 <4> [] local_bh_enable+0x9a/0xb0 <4> [] virtnet_napi_enable+0x4a/0x60 [virtio_net] <4> [] virtnet_open+0x4f/0x60 [virtio_net] <4> [] dev_open+0xa1/0x100 <4> [] dev_change_flags+0xa1/0x1d0 <4> [] do_setlink+0x169/0x8b0 <4> [] ? rtnl_fill_ifinfo+0x946/0xcb0 <4> [] ? nla_parse+0x34/0x110 <4> [] rtnl_setlink+0xee/0x130 <4> [] rtnetlink_rcv_msg+0x2d7/0x340 <4> [] ? socket_has_perm+0x74/0x90 <4> [] ? rtnetlink_rcv_msg+0x0/0x340 <4> [] netlink_rcv_skb+0xa9/0xd0 <4> [] rtnetlink_rcv+0x25/0x40 <4> [] netlink_unicast+0x2db/0x320 <4> [] netlink_sendmsg+0x2c0/0x3d0 <4> [] sock_sendmsg+0x123/0x150 <4> [] ? sock_recvmsg+0x133/0x160 <4> [] ? autoremove_wake_function+0x0/0x40 <4> [] ? lru_cache_add_lru+0x21/0x40 <4> [] ? page_add_new_anon_rmap+0x9d/0xf0 <4> [] ? handle_pte_fault+0x4af/0xb00 <4> [] ? move_addr_to_kernel+0x64/0x70 <4> [] __sys_sendmsg+0x406/0x420 <4> [] ? __do_page_fault+0x1ec/0x480 <4> [] ? sys_sendto+0x139/0x190 <4> [] ? kvm_clock_read+0x1c/0x20 <4> [] sys_sendmsg+0x49/0x90 <4> [] system_call_fastpath+0x16/0x1b <4>Code: 83 e0 00 00 00 00 10 00 00 48 03 93 d0 00 00 00 66 83 42 04 01 8b 93 cc 00 00 00 48 8b b3 d0 00 00 00 80 4c 16 10 20 44 2b 68 0c <4d> 8b 76 10 75 89 e9 d1 fd ff ff 0f 1f 40 00 a8 02 74 0d 0f b6 <1>RIP [] virtnet_poll+0x4f9/0x910 [virtio_net] <4> RSP <4>CR2: 0000000000000010