Strange stacktrace with the kernel 4.9-rc3

[Mikulas Patocka]

Hi

I've got these two stacktraces with the kernel 4.9-rc3. The strange thing 
is that the kernel doesn't say what kind of problem happened - just a 
register dump and stack trace.

It happened on virtual machine guest running in qemu-kvm.

Mikulas


[  166.917189] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc3+ #1
[  166.917194] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  166.917199] task: ffffffff8160c4c0 task.stack: ffffffff81600000
[  166.917202] RIP: 0010:[<ffffffff813157e2>]  [<ffffffff813157e2>] native_safe_halt+0x2/0x10
[  166.917399] RSP: 0018:ffffffff81603f38  EFLAGS: 00000246
[  166.917402] RAX: 0000000000080000 RBX: 0000000000000000 RCX: 0100000000000000
[  166.917405] RDX: 0140000000000000 RSI: 0100000000000000 RDI: 0000000000000046
[  166.917408] RBP: ffffffff8160c4c0 R08: 0000000000000000 R09: 0000000000000000
[  166.917410] R10: 0000000000000000 R11: 000000000000d400 R12: ffffffff81650ab8
[  166.917412] R13: ffffffff8160c4c0 R14: ffffffff8160c4c0 R15: ffffffff81603fb0
[  166.917433] FS:  0000000000000000(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
[  166.917435] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  166.917438] CR2: 00000000017d9c0c CR3: 000000011a34c000 CR4: 00000000000006b0
[  166.917454] Stack:
[  166.917457]  ffffffff81315765 ffffffff81079bec 000000971fffa740 ffffffffffffffff
[  166.917464]  ffff88011fffa740 ffffffff816d8920 ffffffff816e00a0 ffffffff81719000
[  166.917470]  ffffffff8166edc3 ffffffff816e00a0 0000000000000020 ffffffff8166e120
[  166.917475] Call Trace:
[  166.917512]  [<ffffffff81315765>] ? default_idle+0x5/0x10
[  166.917619]  [<ffffffff81079bec>] ? cpu_startup_entry+0xac/0x150
[  166.917631]  [<ffffffff8166edc3>] ? start_kernel+0x385/0x38d
[  166.917636]  [<ffffffff8166e120>] ? early_idt_handler_array+0x120/0x120
[  166.917642]  [<ffffffff8166e375>] ? x86_64_start_kernel+0xea/0xf9
[  166.917644] Code: 04 25 c0 c2 00 00 f0 80 60 02 df c3 0f ae f0 0f ae 38 0f ae f0 eb c8 fb 66 66 90 66 66 90 eb dd 66 0f 1f 84 00 00 00 00 00 fb f4 <c3> 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90
[  168.503352] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc3+ #1
[  168.503357] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  168.503362] task: ffffffff8160c4c0 task.stack: ffffffff81600000
[  168.503365] RIP: 0010:[<ffffffff813157e2>]  [<ffffffff813157e2>] native_safe_halt+0x2/0x10
[  168.503383] RSP: 0018:ffffffff81603f38  EFLAGS: 00000246
[  168.503387] RAX: 0000000000080000 RBX: 0000000000000000 RCX: 0100000000000000
[  168.503390] RDX: 0140000000000000 RSI: 0100000000000000 RDI: 0000000000000046
[  168.503392] RBP: ffffffff8160c4c0 R08: 0000000000000000 R09: 0000000000000000
[  168.503395] R10: 0000000000000000 R11: 0000000000010400 R12: ffffffff81650ab8
[  168.503397] R13: ffffffff8160c4c0 R14: ffffffff8160c4c0 R15: ffffffff81603fb0
[  168.503416] FS:  0000000000000000(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
[  168.503419] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  168.503422] CR2: 00000000017d9c0c CR3: 000000011a34c000 CR4: 00000000000006b0
[  168.503430] Stack:
[  168.503433]  ffffffff81315765 ffffffff81079bec 000000971fffa740 ffffffffffffffff
[  168.503440]  ffff88011fffa740 ffffffff816d8920 ffffffff816e00a0 ffffffff81719000
[  168.503446]  ffffffff8166edc3 ffffffff816e00a0 0000000000000020 ffffffff8166e120
[  168.503517] Call Trace:
[  168.503527]  [<ffffffff81315765>] ? default_idle+0x5/0x10
[  168.503534]  [<ffffffff81079bec>] ? cpu_startup_entry+0xac/0x150
[  168.503544]  [<ffffffff8166edc3>] ? start_kernel+0x385/0x38d
[  168.503550]  [<ffffffff8166e120>] ? early_idt_handler_array+0x120/0x120
[  168.503556]  [<ffffffff8166e375>] ? x86_64_start_kernel+0xea/0xf9
[  168.503558] Code: 04 25 c0 c2 00 00 f0 80 60 02 df c3 0f ae f0 0f ae 38 0f ae f0 eb c8 fb 66 66 90 66 66 90 eb dd 66 0f 1f 84 00 00 00 00 00 fb f4 <c3> 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90