On Fri, 2013-03-15 at 15:41 +0800, Jason Wang wrote: > Some drivers depends on transport_header to do packet transmission, but it was > unset in some cases (one example is macvtap driver which build skbs from > userspace and generate CHECKSUM_NONE packets). The driver may crash in those > cases since the transport_header was not valid. The problem becomes more > obvious > since commit fda55eca5a33f33ffcd4192c6b2d75179714a52c (net: introduce > skb_transport_header_was_set()) since it initializes transport_header to ~0U. > > So before passing the skb to driver, this patch reset the transport_header if > it > was not set to avoid such crash such as: > > hp-z800-04.qe.lab.eng.nay.redhat.com login: BUG: unable to handle kernel > paging > request at ffff8805166f760c > IP: [<ffffffffa035a5d0>] ixgbe_xmit_frame_ring+0x220/0x5e0 [ixgbe] > PGD 1ece067 PUD 0 > Oops: 0000 [#1] SMP > Modules linked in: vhost_net tun nfsv3 nfs_acl nfsv4 auth_rpcgss nfs fscache > lockd autofs4 sunrpc openvswitch ipv6 iTCO_wdt iTCO_vendor_support hp_wmi > sparse_keymap rfkill acpi_cpufreq freq_table mperf coretemp kvm_intel kvm > crc32c_intel ghash_clmulni_intel microcode serio_raw pcspkr sg lpc_ich > mfd_core > tg3 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 i7core_edac > edac_core ixgbe dca ptp pps_core mdio ext4(F) mbcache(F) jbd2(F) sd_mod(F) > crc_t10dif(F) sr_mod(F) cdrom(F) firewire_ohci(F) firewire_core(F) > crc_itu_t(F) > aesni_intel(F) ablk_helper(F) cryptd(F) lrw(F) aes_x86_64(F) xts(F) > gf128mul(F) > floppy(F) mptsas(F) mptscsih(F) mptbase(F) scsi_transport_sas(F) ahci(F) > libahci(F) nouveau(F) ttm(F) drm_kms_helper(F) drm(F) i2c_algo_bit(F) > i2c_core(F) mxm_wmi(F) video(F) wmi(F) dm_mirror(F) dm_region_hash(F) > dm_log(F) > dm_mod(F) [last unloaded: tun] > CPU 6 > Pid: 17337, comm: vhost-17317 Tainted: GF 3.9.0-rc1+ #7 > Hewlett-Packard HP Z800 Workstation/0AECh > RIP: 0010:[<ffffffffa035a5d0>] [<ffffffffa035a5d0>] > ixgbe_xmit_frame_ring+0x220/0x5e0 [ixgbe] > RSP: 0018:ffff880222cddb18 EFLAGS: 00010286 > RAX: 00000000ffffffff RBX: ffff880416b4b000 RCX: ffff8805166f75ff > RDX: 0000000000000008 RSI: ffff8804166f760e RDI: 0000000000000007 > RBP: ffff880222cddb68 R08: 0000000000000008 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90009dce120 > R13: ffff880416b4b300 R14: 0000000000000000 R15: ffff8804118f0800 > FS: 0000000000000000(0000) GS:ffff88042fc40000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > CR2: ffff8805166f760c CR3: 000000041e98c000 CR4: 00000000000027e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process vhost-17317 (pid: 17337, threadinfo ffff880222cdc000, task > ffff8802211d4040) > Stack: > 00000000ffffffff 0000000000000180 ffff880222cddbb7 0000000000000180 > ffff880222cddb48 ffff88040d5dd1c0 ffff8804118f0000 0000000000000036 > ffff8804118f0000 ffff8804165d7a9c ffff880222cddb88 ffffffffa035a9d3 > Call Trace: > [<ffffffffa035a9d3>] ixgbe_xmit_frame+0x43/0x90 [ixgbe] > [<ffffffff8149d54a>] dev_hard_start_xmit+0x12a/0x570 > [<ffffffff814bd8da>] sch_direct_xmit+0xfa/0x1d0 > [<ffffffff8149db28>] dev_queue_xmit+0x198/0x4c0 > [<ffffffff813d23fa>] macvlan_start_xmit+0x6a/0x170 > [<ffffffff813d3974>] macvtap_get_user+0x404/0x4e0 > [<ffffffff813d3a7b>] macvtap_sendmsg+0x2b/0x30 > [<ffffffffa06d9efa>] handle_tx+0x34a/0x680 [vhost_net] > [<ffffffffa06da265>] handle_tx_kick+0x15/0x20 [vhost_net] > [<ffffffffa06d7dfc>] vhost_worker+0x10c/0x1c0 [vhost_net] > [<ffffffffa06d7cf0>] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net] > [<ffffffffa06d7cf0>] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net] > [<ffffffff8107b77e>] kthread+0xce/0xe0 > [<ffffffff8107b6b0>] ? kthread_freezable_should_stop+0x70/0x70 > [<ffffffff815749ec>] ret_from_fork+0x7c/0xb0 > [<ffffffff8107b6b0>] ? kthread_freezable_should_stop+0x70/0x70 > Code: 34 31 0f 84 d3 01 00 00 66 83 fa 08 0f 85 b9 00 00 00 80 7e 09 06 0f 85 > af > 00 00 00 8b 80 cc 00 00 00 48 01 c1 0f 84 a0 00 00 00 <0f> b6 41 0d a8 01 0f > 85 > 94 00 00 00 a8 02 75 0a 41 3a 7d 5c 0f > RIP [<ffffffffa035a5d0>] ixgbe_xmit_frame_ring+0x220/0x5e0 [ixgbe] > RSP <ffff880222cddb18> > CR2: ffff8805166f760c > > Cc: Eric Dumazet <eduma...@google.com> > Signed-off-by: Jason Wang <jasow...@redhat.com> > --- > net/core/dev.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/net/core/dev.c b/net/core/dev.c > index 480114d..db315a1 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -2525,6 +2525,9 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct > net_device *dev, > } > } > > + if (!skb_transport_header_was_set(skb)) > + skb_reset_transport_header(skb); > + > if (!list_empty(&ptype_all)) > dev_queue_xmit_nit(skb, dev); >
Hmm... This really looks strange. Any way we can avoid adding this to fast path, for people not using macvtap and ixgbe ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/