Re: [Xen-devel] HV crash with PVOPS kernel on 32bit

[Keir Fraser <keir@xxxxxxx>]

On 09/11/2010 20:23, "Keir Fraser" <keir@xxxxxxx> wrote:

> On 09/11/2010 19:53, "Conny Seidel" <conny.seidel@xxxxxxx> wrote:
> 
>> Hi,
>> 
>> we see a XEN HV panic on a 32bit PVOPS kernel.
>> 
>> XEN version:  XEN-unstable 22365-0d5f09e3728c 32bit
>> PVOPS Kernel: origin/xen/stable commit id: 6c72eadd1 32bit
>> used BaseOS:  SLES11 SP1 32bit
> 
> You could avoid this issue by specifying iommu=0 on the Xen command line. If
> AMD IOMMU support is buggy then we could disable iommu by default?

The specific problem here is that a lock is being acquired with IRQs
disabled (it is presumably an IRQ-safe lock), but previously it was acquired
with IRQs enabled. That's not allowed. Perhaps this is confusion over
whether iommu->lock is supposed to be IRQ-safe or not? Just a theory. An
engineer with knowledge of that code should go take a look.

 -- Keir

>  -- Keir
> 
>> (XEN) Xen BUG at spinlock.c:28
>> (XEN) ----[ Xen-4.1-unstable  x86_32p  debug=y  Not tainted ]----
>> (XEN) CPU:    0
>> (XEN) EIP:    e008:[<ff11cabb>] check_lock+0x3b/0x48
>> (XEN) EFLAGS: 00010046   CONTEXT: hypervisor
>> (XEN) eax: 00000000   ebx: 00000001   ecx: ff2f9924   edx: 00000000
>> (XEN) esi: ff2f9920   edi: 00082000   ebp: ff247da8   esp: ff247da4
>> (XEN) cr0: 8005003b   cr4: 000006f0   cr3: 00b66c80   cr2: c18498fc
>> (XEN) ds: e010   es: e010   fs: 00d8   gs: 0000   ss: e010   cs: e008
>> (XEN) Xen stack trace from esp=ff247da4:
>> (XEN)    00000082 ff247db8 ff11cb91 00000001 00000000 ff247e18 ff13d17b
>> ff2f9920
>> (XEN)    ff10e68f 0000b760 ff114bee 0000000a 00000022 000000a0 ff276c48
>> ff2f9920
>> (XEN)    000000a0 01016024 00000000 0000002f 00000000 00000002 0000000c
>> 00000001
>> (XEN)    00000960 01000000 00000022 ff2ef074 00000960 ff247e38 ff131348
>> 00000000
>> (XEN)    00000022 00000960 ff13140b 00000000 00000022 ff247e68 ff14b306
>> 00000000
>> (XEN)    00000022 00000960 ff11cb91 fffeffff 00000000 01247e78 00000009
>> 00000000
>> (XEN)    00000082 ff247e78 ff14b38b 00000009 ffb80500 ff247e98 ff14b3d7
>> 00000009
>> (XEN)    ff274680 00000046 00000009 ffb80500 ff298fa8 ff247ee8 ff150e3b
>> 00000009
>> (XEN)    ff14e72d ffb80500 00000000 ff2b0ae4 ecc77e18 ff247ec8 00000009
>> ffb80500
>> (XEN)    ff298fa8 ffb80500 00000000 00000000 00000000 00000000 00000012
>> 00000033
>> (XEN)    ecc77ec4 ff247f88 ff106490 ffb66000 00000009 00000000 53472072
>> 0d392049
>> (XEN)    4950000a 6f662043 00000000 00002a70 c11f5ce6 ffb66000 00000001
>> 940a45fe
>> (XEN)    00000001 ff247f78 ff11f366 ff274680 00000009 ffb66000 ff282000
>> ff28c810
>> (XEN)    00000012 ff28207c f8ac3fe8 909090ff 90909090 c390ee90 ff274700
>> ff274680
>> (XEN)    ff276f60 ff276f64 00000009 00000000 c1749698 ff247fee ffb66000
>> 00000020
>> (XEN)    ff247fa8 00db803b ff1d247b 00000002 ecc77ec4 deadbeef deadbeef
>> deadbeef
>> (XEN)    deadbeef c1002407 00000020 00000002 ecc77ec4 ecc77ec4 ffffffda
>> ecc30090
>> (XEN)    ecc77eb8 00000020 000d0000 c1002407 00000061 00000286 ecc77e84
>> 0000e021
>> (XEN)    0000007b 0000007b 000000d8 00000000 00000000 ffb66000 00000000
>> (XEN) Xen call trace:
>> (XEN)    [<ff11cabb>] check_lock+0x3b/0x48
>> (XEN)    [<ff11cb91>] _spin_lock_irqsave+0x1b/0x5d
>> (XEN)    [<ff13d17b>] amd_iommu_ioapic_update_ire+0x17d/0x252
>> (XEN)    [<ff131348>] iommu_update_ire_from_apic+0x46/0x48
>> (XEN)    [<ff14b306>] __modify_IO_APIC_irq+0xb5/0x125
>> (XEN)    [<ff14b38b>] __unmask_IO_APIC_irq+0x15/0x17
>> (XEN)    [<ff14b3d7>] startup_edge_ioapic_irq+0x4a/0x69
>> (XEN)    [<ff150e3b>] pirq_guest_bind+0x2d5/0x48a
>> (XEN)    [<ff106490>] do_event_channel_op+0x997/0xe97
>> (XEN)    [<ff1d247b>] hypercall+0xbb/0xdb
>> (XEN)
>> (XEN)
>> (XEN) ****************************************
>> (XEN) Panic on CPU 0:
>> (XEN) Xen BUG at spinlock.c:28
>> (XEN) ****************************************
>> (XEN)
>> 
>> 
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> 
> 



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