Hi all,
We met BUG_ON in do_device_not_available(fpu exception handler) when run
redhat7 in kvm guest,
and there is no special test on this guest, only some network packet receipt
and transmission.
I checked the new kernel version, found this commit
4ecd16ec7059390b430af34bd8bc3ca2b5dcef9a
Author: Andy Lutomirski <l...@kernel.org>
Date: Sun Jan 24 14:38:06 2016 -0800
x86/fpu: Fix math emulation in eager fpu mode
Systems without an FPU are generally old and therefore use lazy FPU
switching. Unsurprisingly, math emulation in eager FPU mode is a
bit buggy. Fix it.
There were two bugs involving kernel code trying to use the FPU
registers in eager mode even if they didn't exist and one BUG_ON()
that was incorrect.
The BUG_ON() is incorrect, but I have no idea about eager fpu, why the BUG_ON
is incorrect?
Should we backport the patch to v3.10, or is there some bugs in the qemu-kvm?
Any reply will be appreciated.
Thanks,
Kefeng
[1] BUG_ON
----------------------------------------------------
[347134.486436] ------------[ cut here ]------------
[347134.487310] kernel BUG at arch/x86/kernel/traps.c:643!
[347134.487398] invalid opcode: 0000 [#1] SMP
[347134.500532] Modules linked in:loop binfmt_misc nf_log_ipv4 nf_log_common
xt_LOG softdog ipmi_devintf ipmi_msghandler xfs libcrc32c tipc squashfs
ipt_REJECT iptable_filter ip_tables dm_mod crct10dif_pclmul crct10dif_common
crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel lrw ppdev gf128mul
i2c_piix4 glue_helper ablk_helper i2c_core cryptd serio_raw parport_pc parport
pcspkr ext3 mbcache jbd ata_generic pata_acpi virtio_console(OVE)
virtio_blk(OVE) virtio_balloon(OVE) virtio_net(OVE) ata_piix libata floppy
virtio_pci(OVE) virtio_ring(OVE) virtio(OVE)
[347134.525182] CPU: 5 PID: 0 Comm: swapper/5 Tainted: G O E
----V------- 3.10.0-229.20.1.x86_64 #1 SMP Mon Apr 18 11:26:55 UTC 2016
[347134.525182] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.8.1-0-g4adadbd-20160318_175052-HGH1000008214 04/01/2014
[347134.525182] task: ffff8803fa2c5c00 ti: ffff8803fa2ec000 task.ti:
ffff8803fa2ec000
[347134.525182] RIP: 0010:[<ffffffff8160fb13>] [<ffffffff8160fb13>]
do_device_not_available+0x13/0x60
[347134.525182] RSP: 0018:ffff8803fa2abc80 EFLAGS: 00010046
[347134.525182] RAX: 000000008160ecec RBX: 0000000000000000 RCX:
ffffffff8160ecec
[347134.525182] RDX: 00000000ffffffff RSI: 0000000000000000 RDI:
ffff8803fa2abc98
[347134.525182] RBP: ffff8803fa2abc88 R08: 0000000000000000 R09:
0000000000000000
[347134.525182] R10: 0000000000000001 R11: 0000000000000005 R12:
ffff8803fa2c5c00
[347134.525182] R13: ffff88040f550a40 R14: ffff8803fa2c6298 R15:
0000000000000005
[347134.544262] FS: 0000000000000000(0000) GS:ffff88040f540000(0000)
knlGS:0000000000000000
[347134.544262] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[347134.544262] CR2: 00007f15a4ac0e30 CR3: 00000003f5081000 CR4:
00000000000407e0
[347134.544262] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[347134.544262] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
0000000000000400
[347134.544262] Stack:
[347134.544262] 0000000000000001 ffff8803fa2abd88 ffffffff81618d8e
0000000000000005
[347134.544262] ffff8803fa2c6298 ffff88040f550a40 ffff8803fa2c5c00
ffff8803fa2abd88
[347134.544262] ffff8803fa284500 0000000000000005 0000000000000001
0000000000000000
[347134.544262] Call Trace:
[347134.544262] Code: 81 a4 24 90 00 00 00 ff fe ff ff e9 df fe ff ff e8 c3 f5
a5 ff 0f 1f 00 66 66 66 66 90 55 48 89 e5 53 66 66 66 66 90 31 db 66 90 <0f> 0b
0f 1f 00 65 8b 1c 25 74 f1 00 00 e8 fb 86 b4 ff eb ea 66
[347134.544262] RIP [<ffffffff8160fb13>] do_device_not_available+0x13/0x60
[347134.544262] RSP <ffff8803fa2abc80>
[347134.580457] ---[ end trace 7c0ed2be7ded5c73 ]---
[347134.580457] Kernel panic - not syncing: Fatal exception
[347134.580457] Shutting down cpus with NMI
[2] The /proc/cpuinfo shows below(show only the first cpu0),
--------------------------------
localhost:~ # cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 45
model name : Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz
stepping : 7
microcode : 0x1
cpu MHz : 2899.992
cache size : 4096 KB
physical id : 0
siblings : 8
core id : 0
cpu cores : 8
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm
constant_tsc arch_perfmon rep_good nopl eagerfpu pni pclmulqdq ssse3 cx16 pcid
sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx hypervisor lahf_lm
xsaveopt
bogomips : 5799.98
clflush size : 64
cache_alignment : 64
address sizes : 42 bits physical, 48 bits virtual
power management:
