On Wed, Jul 06, 2016 at 01:45:58PM -0400, Craig Gallek wrote: > On Thu, Jun 30, 2016 at 2:45 AM, Jason Wang <jasowang@xxxxxxxxxx> wrote: > > Hi all: > > > > This series tries to switch to use skb array in tun. This is used to > > eliminate the spinlock contention between producer and consumer. The > > conversion was straightforward: just introdce a tx skb array and use > > it instead of sk_receive_queue. > > I'm seeing the splat below after this series. I'm still wrapping my > head around this code, but it appears to be happening because the > tun_struct passed into tun_queue_resize is uninitialized. > Specifically, iteration over the disabled list_head fails because prev > = next = NULL. This seems to happen when a startup script on my test > machine changes the queue length. I'll try to figure out what's > happening, but if it's obvious to someone else from the stack, please > let me know. Uploading your .config might help BTW. > [ 72.322236] BUG: unable to handle kernel NULL pointer dereference > at 0000000000000010 > [ 72.329993] IP: [<ffffffff8153c1a0>] tun_device_event+0x110/0x340 > [ 72.336032] PGD 7f054f1067 PUD 7ef6f3f067 PMD 0 > [ 72.340616] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC > [ 72.345498] gsmi: Log Shutdown Reason 0x03 > [ 72.349541] Modules linked in: w1_therm wire cdc_acm ehci_pci > ehci_hcd mlx4_en ib_uverbs mlx4_ib ib_core mlx4_core > [ 72.359870] CPU: 12 PID: 7820 Comm: set.ixion-haswe Not tainted > 4.7.0-dbx-DEV #10 > [ 72.360253] mlx4_en: eth0: Link Up > [ 72.370618] Hardware name: Intel Grantley,Wellsburg/Ixion_IT_15, > BIOS 2.50.0 01/21/2016 > [ 72.378525] task: ffff883f2501e8c0 ti: ffff883f3ef08000 task.ti: > ffff883f3ef08000 > [ 72.385917] RIP: 0010:[<ffffffff8153c1a0>] [<ffffffff8153c1a0>] > tun_device_event+0x110/0x340 > [ 72.394353] RSP: 0018:ffff883f3ef0bbe8 EFLAGS: 00010202 > [ 72.399599] RAX: fffffffffffffae8 RBX: ffff887ef9883378 RCX: 0000000000000000 > [ 72.406647] RDX: 0000000000000000 RSI: 0000000000000028 RDI: 0000000000000000 > [ 72.413694] RBP: ffff883f3ef0bc58 R08: 0000000000000000 R09: 0000000000000001 > [ 72.420742] R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000010 > [ 72.427789] R13: 0000000000000000 R14: 0000000000000001 R15: ffff883f3ef0bd10 > [ 72.434837] FS: 00007fac4e5dd700(0000) GS:ffff883f7f700000(0000) > knlGS:0000000000000000 > [ 72.442832] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 72.448507] CR2: 0000000000000010 CR3: 0000007ef66ac000 CR4: 00000000001406e0 > [ 72.455555] Stack: > [ 72.457541] ffff883f3ef0bc18 0000000000000246 000000000000001e > ffff887ef9880000 > [ 72.464880] ffff883f3ef0bd10 0000000000000000 0000000000000000 > ffffffff00000000 > [ 72.472219] ffff883f3ef0bc58 ffffffff81d24070 00000000fffffff9 > ffffffff81cec7a0 > [ 72.479559] Call Trace: > [ 72.481986] [<ffffffff810eeb0d>] notifier_call_chain+0x5d/0x80 > [ 72.487844] [<ffffffff816365c0>] ? show_tx_maxrate+0x30/0x30 > [ 72.493520] [<ffffffff810eeb3e>] __raw_notifier_call_chain+0xe/0x10 > [ 72.499801] [<ffffffff810eeb56>] raw_notifier_call_chain+0x16/0x20 > [ 72.506001] [<ffffffff8160eb30>] call_netdevice_notifiers_info+0x40/0x70 > [ 72.512706] [<ffffffff8160ec36>] call_netdevice_notifiers+0x16/0x20 > [ 72.518986] [<ffffffff816365f8>] change_tx_queue_len+0x38/0x80 > [ 72.524838] [<ffffffff816381cf>] netdev_store.isra.5+0xbf/0xd0 > [ 72.530688] [<ffffffff81638330>] tx_queue_len_store+0x50/0x60 > [ 72.536459] [<ffffffff814a6798>] dev_attr_store+0x18/0x30 > [ 72.541888] [<ffffffff812ea3ff>] sysfs_kf_write+0x4f/0x70 > [ 72.547306] [<ffffffff812e9507>] kernfs_fop_write+0x147/0x1d0 > [ 72.553077] [<ffffffff81134a4f>] ? rcu_read_lock_sched_held+0x8f/0xa0 > [ 72.559534] [<ffffffff8125a108>] __vfs_write+0x28/0x120 > [ 72.564781] [<ffffffff8111b137>] ? percpu_down_read+0x57/0x90 > [ 72.570542] [<ffffffff8125d7d8>] ? __sb_start_write+0xc8/0xe0 > [ 72.576303] [<ffffffff8125d7d8>] ? __sb_start_write+0xc8/0xe0 > [ 72.582063] [<ffffffff8125bd5e>] vfs_write+0xbe/0x1b0 > [ 72.587138] [<ffffffff8125c092>] SyS_write+0x52/0xa0 > [ 72.592135] [<ffffffff817528a5>] entry_SYSCALL_64_fastpath+0x18/0xa8 > [ 72.598497] Code: 45 31 f6 48 8b 93 78 33 00 00 48 81 c3 78 33 00 > 00 48 39 d3 48 8d 82 e8 fa ff ff 74 25 48 8d b0 40 05 00 00 49 63 d6 > 41 83 c6 01 <49> 89 34 d4 48 8b 90 18 05 00 00 48 39 d3 48 8d 82 e8 fa > ff ff > [ 72.617767] RIP [<ffffffff8153c1a0>] tun_device_event+0x110/0x340 > [ 72.623883] RSP <ffff883f3ef0bbe8> > [ 72.627327] CR2: 0000000000000010 > [ 72.630638] ---[ end trace b0c54137cf861b91 ]--- -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
