Re: [Xen-devel] Alignment check on domU (2.6.32)

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

On 03/29/2010 08:08 PM, Natalie Protasevich wrote:
> Hello,
> We are getting alignment check with 2.6.32 kernel running as a domU on 
> an AMD system, 
Which 2.6.32 is it?  Is it stock kernel.org, from xen.git, a distro, 
elsewhere?
> while dom0 is a 2.6.18 kernel.
> As far as I know we should not have run into such problem, since this 
> is x86_64 kernel. I am aware of the fact that for alignment check trap 
> AC bit needs to be set in eflags and AM should be set in CR0. I 
> tracked cr0 and AM was getting set, and problem was occurring when 
> something was setting AC flag at the time of calling memcpy_c(). I 
> cheated and cleared the AM flag in cr0 (as one can see in this trace) 
> but this didn't help. I haven't figured out what sets the AM flag...
Do you have any other domains running at the time?

What CPU is this?

Does it run the same kernel native OK?

    J

> Here is the trace:
>
> [   80.342300] alignment check: 0000 [#1] SMP
> [   80.342323] last sysfs file: /sys/devices/virtual/vc/vcsa7/dev
> [   80.342330] CPU 1
> [   80.342339] Pid: 3875, comm: loas_check Not tainted 
> 2.6.32.10+drm33.1 #12
> [   80.342347] RIP: e030:[<ffffffff813eb2bb>]  [<ffffffff813eb2bb>] 
> memcpy_c+0xb/0x20
> [   80.342365] RSP: e02b:ffff88015556d9b0  EFLAGS: 00050246
> [   80.342371] RAX: ffff88017360cc8c RBX: ffff880176d91900 RCX: 
> 0000000000000002
> [   80.342379] RDX: 0000000000000000 RSI: ffff880176d91958 RDI: 
> ffff88017360cc8c
> [   80.342388] RBP: ffff88015556d9e8 R08: ffffffff81570260 R09: 
> ffffffff81ae8840
> [   80.342395] R10: 0000000000000000 R11: 0000000000000000 R12: 
> 0000000000000000
> [   80.342403] R13: 000000000000000e R14: ffff880173f3fc00 R15: 
> ffff880176d91958
> [   80.342417] FS:  00007f0f4dafd6e0(0000) GS:ffff880028047000(0000) 
> knlGS:0000000000000000
> [   80.342425] CS:  e033 DS: 002b ES: 002b CR0: 000000008001003b
> [   80.342432] CR2: 00007f0f4db1a000 CR3: 000000017362d000 CR4: 
> 0000000000000660
> [   80.342440] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
> 0000000000000000
> [   80.342448] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 
> 0000000000000000
> [   80.342457] Process loas_check (pid: 3875, threadinfo 
> ffff88015556c000, task ffff8801556cada0)
> [   80.342465] Stack:
> [   80.342469]  ffffffff8157038f ffffffff81ae8840 ffff880173f3fc00 
> 0000000000000000
> [   80.342483] <0> ffff880173f3fc00 ffff880161a36400 0000000000000000 
> ffff88015556da08
> [   80.342500] <0> ffffffff815705d6 ffff880180000000 ffff880173f3fc00 
> ffff88015556da28
> [   80.342518] Call Trace:
> [   80.342528]  [<ffffffff8157038f>] ? ip_finish_output+0x12f/0x2f0
> [   80.342538]  [<ffffffff815705d6>] ip_output+0x86/0xd0
> [   80.342546]  [<ffffffff8156f600>] ip_local_out+0x20/0x30
> [   80.342555]  [<ffffffff8156fed3>] ip_queue_xmit+0x223/0x3f0
> [   80.342565]  [<ffffffff81584214>] ? tcp_send_active_reset+0x24/0x180
> [   80.342576]  [<ffffffff8100dcfd>] ? xen_force_evtchn_callback+0xd/0x10
> [   80.342586]  [<ffffffff8100e532>] ? check_events+0x12/0x20
> [   80.342595]  [<ffffffff81583dd2>] tcp_transmit_skb+0x402/0x780
> [   80.342604]  [<ffffffff81584279>] tcp_send_active_reset+0x89/0x180
> [   80.342614]  [<ffffffff815770bc>] tcp_disconnect+0x6c/0x3c0
> [   80.342622]  [<ffffffff81576e34>] tcp_close+0x3e4/0x480
> [   80.342632]  [<ffffffff81598b92>] inet_release+0x42/0x70
> [   80.342643]  [<ffffffff814ce5d8>] sock_release+0x18/0x60
> [   80.342652]  [<ffffffff814ceab2>] sock_close+0x12/0x30
> [   80.342663]  [<ffffffff8110e28e>] __fput+0xee/0x200
> [   80.342671]  [<ffffffff8100dcfd>] ? xen_force_evtchn_callback+0xd/0x10
> [   80.342681]  [<ffffffff8110e3b7>] fput+0x17/0x20
> [   80.342690]  [<ffffffff8110a378>] filp_close+0x58/0x90
> [   80.342698]  [<ffffffff8100e51f>] ? xen_restore_fl_direct_end+0x0/0x1
> [   80.342709]  [<ffffffff8105691c>] put_files_struct+0xcc/0xe0
> [   80.342718]  [<ffffffff81056980>] exit_files+0x50/0x60
> [   80.342726]  [<ffffffff81058587>] do_exit+0x1b7/0x7f0
> [   80.342735]  [<ffffffff81065cb6>] ? __dequeue_signal+0x16/0x160
> [   80.342745]  [<ffffffff81058bfc>] do_group_exit+0x3c/0xa0
> [   80.342754]  [<ffffffff81068328>] get_signal_to_deliver+0x1b8/0x380
> [   80.342764]  [<ffffffff810106a9>] do_notify_resume+0xc9/0x8a0
> [   80.342775]  [<ffffffff8100b8bb>] ? xen_mc_flush+0x11b/0x1d0
> [   80.342786]  [<ffffffff8102cb52>] ? 
> paravirt_end_context_switch+0x12/0x30
> [   80.342798]  [<ffffffff81047afb>] ? finish_task_switch+0x5b/0xb0
> [   80.342808]  [<ffffffff8101134e>] int_signal+0x12/0x17
> [   80.342815] Code: 81 ea d8 1f 00 00 48 3b 42 20 73 07 48 8b 50 f9 
> 31 c0 c3 31 d2 48 c7 c0 f2 ff ff ff c3 90 90 90 48 89 f8 89 d1 c1 e9 
> 03 83 e2 07 <f3> 48 a5 89 d1 f3 a4 c3 66 66 66 66 2e 0f 1f 84 00 00 00 
> 00 00
> [   80.342952] RIP  [<ffffffff813eb2bb>] memcpy_c+0xb/0x20
> [   80.342962]  RSP <ffff88015556d9b0>
> [   80.342969] ---[ end trace 1442aa6e9e3d337d ]---
> [   80.342976] Fixing recursive fault but reboot is needed!
>
> This happens 2 out of 3 times.
> I don't seem to find any similar recent reports and relevant commits 
> so far, and we haven't had such problem running 2.6.24 domU (Ubuntu 
> hardy) on the 2.6.18 dom0. I'm hoping someone can give a hand.
> Thanks,
> --Natalie
> P.S. Just in case - here is the "original" trace before I tried to 
> modify the cr0:
> [   64.544616] alignment check: 0000 [#1] SMP
> [   64.544640] last sysfs file: /sys/devices/virtual/vc/vcsa7/dev
> [   64.544647] CPU 1
> [   64.544655] Pid: 3737, comm: loas_check Not tainted 
> 2.6.32.10+drm33.1 #8
> [   64.544663] RIP: e030:[<ffffffff813eb23b>]  [<ffffffff813eb23b>] 
> memcpy_c+0xb/0x20
> [   64.544681] RSP: e02b:ffff880152e7d9b0  EFLAGS: 00050246
> [   64.544687] RAX: ffff8801731e4c8c RBX: ffff880178185400 RCX: 
> 0000000000000002
> [   64.544696] RDX: 0000000000000000 RSI: ffff880178185458 RDI: 
> ffff8801731e4c8c
> [   64.544703] RBP: ffff880152e7d9e8 R08: ffffffff81570110 R09: 
> ffffffff81ae6840
> [   64.544711] R10: 0000000000000000 R11: 0000000000000000 R12: 
> 0000000000000000
> [   64.544718] R13: 000000000000000e R14: ffff88017332d800 R15: 
> ffff880178185458
> [   64.544732] FS:  00007fa8de9336e0(0000) GS:ffff880028047000(0000) 
> knlGS:0000000000000000
> [   64.544741] CS:  e033 DS: 002b ES: 002b CR0: 000000008005003b
> [   64.544748] CR2: 00000000081f1320 CR3: 0000000001001000 CR4: 
> 0000000000000660
> [   64.544756] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
> 0000000000000000
> [   64.544764] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 
> 0000000000000000
> [   64.544772] Process loas_check (pid: 3737, threadinfo 
> ffff880152e7c000, task ffff880152e72da0)
> [   64.544781] Stack:
> [   64.544785]  ffffffff81570214 ffffffff81ae6840 ffff88017332d800 
> 0000000000000000
> [   64.544798] <0> ffff88017332d800 ffff880152e13200 0000000000000000 
> ffff880152e7da08
> [   64.544814] <0> ffffffff81570486 ffff880180000000 ffff88017332d800 
> ffff880152e7da28
> [   64.544832] Call Trace:
> [   64.544842]  [<ffffffff81570214>] ? ip_finish_output+0x104/0x2f0
> [   64.544853]  [<ffffffff81570486>] ip_output+0x86/0xd0
> [   64.544862]  [<ffffffff8156f4b0>] ip_local_out+0x20/0x30
> [   64.544870]  [<ffffffff8156fd83>] ip_queue_xmit+0x223/0x3f0
> [   64.544880]  [<ffffffff8100dcfd>] ? xen_force_evtchn_callback+0xd/0x10
> [   64.544889]  [<ffffffff8100e532>] ? check_events+0x12/0x20
> [   64.544900]  [<ffffffff81583c82>] tcp_transmit_skb+0x402/0x780
> [   64.544909]  [<ffffffff81584129>] tcp_send_active_reset+0x89/0x180
> [   64.544920]  [<ffffffff8111e16a>] ? __d_free+0x3a/0x60
> [   64.544929]  [<ffffffff81576f6c>] tcp_disconnect+0x6c/0x3c0
> [   64.544938]  [<ffffffff81576ce4>] tcp_close+0x3e4/0x480
> [   64.544946]  [<ffffffff81598a42>] inet_release+0x42/0x70
> [   64.544956]  [<ffffffff814ce558>] sock_release+0x18/0x60
> [   64.544964]  [<ffffffff814cea32>] sock_close+0x12/0x30
> [   64.544974]  [<ffffffff8110e20e>] __fput+0xee/0x200
> [   64.544982]  [<ffffffff8100dcfd>] ? xen_force_evtchn_callback+0xd/0x10
> [   64.544991]  [<ffffffff8110e337>] fput+0x17/0x20
> [   64.545000]  [<ffffffff8110a2f8>] filp_close+0x58/0x90
> [   64.545009]  [<ffffffff8100e51f>] ? xen_restore_fl_direct_end+0x0/0x1
> [   64.545019]  [<ffffffff8105689c>] put_files_struct+0xcc/0xe0
> [   64.545028]  [<ffffffff81056900>] exit_files+0x50/0x60
> [   64.545036]  [<ffffffff81058507>] do_exit+0x1b7/0x7f0
> [   64.545046]  [<ffffffff81065c36>] ? __dequeue_signal+0x16/0x160
> [   64.545055]  [<ffffffff81058b7c>] do_group_exit+0x3c/0xa0
> [   64.545064]  [<ffffffff810682a8>] get_signal_to_deliver+0x1b8/0x380
> [   64.545073]  [<ffffffff81010649>] do_notify_resume+0xc9/0x880
> [   64.545084]  [<ffffffff8100b8bb>] ? xen_mc_flush+0x11b/0x1d0
> [   64.545095]  [<ffffffff8102cad2>] ? 
> paravirt_end_context_switch+0x12/0x30
> [   64.545106]  [<ffffffff81047a7b>] ? finish_task_switch+0x5b/0xb0
> [   64.545115]  [<ffffffff810112ce>] int_signal+0x12/0x17
> [   64.545121] Code: 81 ea d8 1f 00 00 48 3b 42 20 73 07 48 8b 50 f9 
> 31 c0 c3 31 d2 48 c7 c0 f2 ff ff ff c3 90 90 90 48 89 f8 89 d1 c1 e9 
> 03 83 e2 07 <f3> 48 a5 89 d1 f3 a4 c3 66 66 66 66 2e 0f 1f 84 00 00 00 
> 00 00
> [   64.545252] RIP  [<ffffffff813eb23b>] memcpy_c+0xb/0x20
> [   64.545262]  RSP <ffff880152e7d9b0>
> [   64.545269] ---[ end trace 11cf940a2c626919 ]---
> [   64.545276] Fixing recursive fault but reboot is needed!
>
>
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