linux-kernel - kernel BUG at arch/x86/kernel/traps.c:643! when run Redhat7(v3.10) in kvm guest

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Message-ID: <c8ea48f5-ac62-9d68-41e1-2073d43d5df4@huawei.com>
Date:   Fri, 14 Oct 2016 14:14:42 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
CC:     Andy Lutomirski <luto@...nel.org>,
        "Xiexiuqi (Xie XiuQi)" <xiexiuqi@...wei.com>,
        Oleg Nesterov <oleg@...hat.com>,
        Rik van Riel <riel@...hat.com>,
        Avi Kivity <avi.kivity@...il.com>,
        Gleb Natapov <gleb@...hat.com>
Subject: kernel BUG at arch/x86/kernel/traps.c:643! when run Redhat7(v3.10) in
 kvm guest

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 <luto@...nel.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: