Re: irqfd issue

[Gleb Natapov <gleb@redhat.com>]

On Tue, May 07, 2013 at 04:36:50PM +0800, Asias He wrote:
> On Tue, May 07, 2013 at 11:18:38AM +0300, Gleb Natapov wrote:
> > On Tue, May 07, 2013 at 04:14:50PM +0800, Asias He wrote:
> > > On Tue, May 07, 2013 at 10:55:36AM +0300, Gleb Natapov wrote:
> > > > On Tue, May 07, 2013 at 09:37:30AM +0800, Asias He wrote:
> > > > > Hi,
> > > > > 
> > > > > I am seeing this with linus/master. Any ideas?
> > > > > 
> > > > How reproducible it this? What HEAD are you seeing this with?
> > > 
> > > Almost always. Start a guest with vhost-net on.
> > > 
> > It happens during start or on VM exit? The trace shows do_exit()
> > 
> > > QEMU  : e3351000cd682200835763caca87adf708ed1c65
> > > KERNEL: 51a26ae7a14b85c99c9be470c2d28eeeba0f26a3 
> > > 
> > Can you try with kvm.git next branch?
> 
> With next branch db6ae6158186a17165ef990bda2895ae7594b039,
> 
Can you revert a0f155e9646d5f1c263f6f9aae880151100243bb and try again?

> [   53.386936] device tap0 entered promiscuous mode
> [   53.386990] br0: port 2(tap0) entered forwarding state
> [   53.386997] br0: port 2(tap0) entered forwarding state
> [   80.096275] BUG: unable to handle kernel NULL pointer dereference at           (null)
> [   80.098592] IP: [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30
> [   80.100988] PGD 0 
> [   80.103339] Oops: 0002 [#1] SMP 
> [   80.105668] Modules linked in: vhost_net
> [   80.108005] CPU 6 
> [   80.108026] Pid: 4257, comm: qemu-system-x86 Not tainted 3.9.0-rc3+ #757 Dell Inc. OptiPlex 790/0V5HMK
> [   80.112662] RIP: 0010:[<ffffffff81c0721e>]  [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30
> [   80.115030] RSP: 0018:ffff880221721cc8  EFLAGS: 00010046
> [   80.117365] RAX: 0000000000000100 RBX: ffff88022dcc003f RCX: ffff880221734950
> [   80.119688] RDX: ffff8802208f6ca8 RSI: 000000007fffffff RDI: 0000000000000000
> [   80.121982] RBP: ffff880221721cc8 R08: 0000000000000002 R09: 0000000000000002
> [   80.124230] R10: 00007f7fd01087e0 R11: 0000000000000246 R12: ffff8802208f6ca8
> [   80.126489] R13: 0000000000000080 R14: ffff880223e2a900 R15: 0000000000000000
> [   80.128718] FS:  00007f7fd38488e0(0000) GS:ffff88022dcc0000(0000) knlGS:0000000000000000
> [   80.130921] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   80.133130] CR2: 0000000000000000 CR3: 000000022309f000 CR4: 00000000000427e0
> [   80.135345] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [   80.137543] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [   80.139708] Process qemu-system-x86 (pid: 4257, threadinfo ffff880221720000, task ffff880222bd5640)
> [   80.141887] Stack:
> [   80.144064]  ffff880221721d08 ffffffff810ac5c5 ffff88022431dc00 0000000000000086
> [   80.146316]  0000000000000080 ffff880223e2a900 ffff8802208f6ca8 0000000000000000
> [   80.148558]  ffff880221721d48 ffffffff810ac8fe 0000000000000000 ffff880221734000
> [   80.150784] Call Trace:
> [   80.152975]  [<ffffffff810ac5c5>] __queue_work+0x45/0x2d0
> [   80.155193]  [<ffffffff810ac8fe>] queue_work_on+0x8e/0xa0
> [   80.157374]  [<ffffffff810ac949>] queue_work+0x19/0x20
> [   80.159505]  [<ffffffff81009b6b>] irqfd_deactivate+0x4b/0x60
> [   80.161621]  [<ffffffff8100a69d>] kvm_irqfd+0x39d/0x580
> [   80.163717]  [<ffffffff81007a27>] kvm_vm_ioctl+0x207/0x5b0
> [   80.165832]  [<ffffffff810c9545>] ? update_curr+0xf5/0x180
> [   80.167931]  [<ffffffff811b66e8>] do_vfs_ioctl+0x98/0x550
> [   80.170013]  [<ffffffff810c1f5e>] ? finish_task_switch+0x4e/0xe0
> [   80.172109]  [<ffffffff81c054aa>] ? __schedule+0x2ea/0x710
> [   80.174218]  [<ffffffff811b6bf7>] sys_ioctl+0x57/0x90
> [   80.176338]  [<ffffffff8140ae9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c
> [   80.178467]  [<ffffffff81c0f602>] system_call_fastpath+0x16/0x1b
> [   80.180598] Code: c1 ea 08 38 c2 74 0f 66 0f 1f 44 00 00 f3 90 0f b6 03 38 c2 75 f7 48 83 c4 08 5b c9 c3 55 48 89 e5 66 66 66 66 90 b8 00 01 00 00 <f0> 66 0f c1 07 89 c2 66 c1 ea 08 38 c2 74 0c 0f 1f 00 f3 90 0f 
> [   80.183098] RIP  [<ffffffff81c0721e>] _raw_spin_lock+0xe/0x30
> [   80.185372]  RSP <ffff880221721cc8>
> [   80.187584] CR2: 0000000000000000
> [   80.208627] ---[ end trace 13fb1e4b6e5ab21f ]---
> 
> > --
> > 			Gleb.
> 
> -- 
> Asias

--
			Gleb.