[Xen-devel] Re: grant table unmap failure makes guest unreapable and causes xen oops

[Kip Macy <kip.macy@xxxxxxxxx>]

It looks like some of these problems may have been fixed by check-ins
in the last couple of hours. I'm doing a make world right now.

 -Kip

         

On 7/6/05, Kip Macy <kip.macy@xxxxxxxxx> wrote:
> I just hit this so I don't fully understand it yet, but it looks like
> there may be some race condition with grant_table unmap requests and
> garbage collection of domain memory on crashed guests.
> 
> My centos4 domU isn't finding its init (this may be the breakage in
> file-backed VBDs that Mark mentioned - it was finding it a couple of
> days ago) and thus calls HYPERVISOR_crash:
> 
> Freeing unused kernel memory: 92k freed
> Kernel panic - not syncing: No init found.  Try passing init= option to 
> kernel.
> 
> [root@rs0 ~]# xm list
> Name              Id  Mem(MB)  CPU VCPU(s)  State  Time(s)  Console
> Domain-0           0      251            0         1       r----     1013.3
> rhel4_0               1          0            3         1        ----c
>          0.5     9601
> 
> The following errors show up on the console:
> 
> (XEN) (file=grant_table.c, line=500) Bad handle (0).
> (XEN) (file=grant_table.c, line=500) Bad handle (49152).
> (XEN) (file=grant_table.c, line=500) Bad handle (49792).
> (XEN) (file=grant_table.c, line=500) Bad handle (0).
> (XEN) (file=grant_table.c, line=500) Bad handle (61440).
> 
> And the guest never goes away.
> 
> [root@rs0 ~]# xm destroy 1
> [root@rs0 ~]# xm list
> Name              Id  Mem(MB)  CPU VCPU(s)  State  Time(s)  Console
> Domain-0          0          251        0             1     r----   1208.2
> rhel4_0               1             0        3              1
> ----c        0.5     9601
> 
> restarting xend here is interesting:
> 
> [root@rs0 ~]# xend start
> DBMap>introduceDomain> 1 69067 <EventChannel dom1:0:14 dom2:1:2>
> /domain/4042ebcc-778d-4488-a0bd-6152c42ba98b
> Traceback (most recent call last):
> <snip>
> RuntimeError: (9, 'Bad file descriptor')
> 
> Message from syslogd@rs0 at Wed Jul  6 10:59:17 2005 ...
> rs0 xenstored: xenstored corruption: connection id 0: err Bad address:
> Unknown error 14 (Bad address)
> Exception starting xend: (9, 'Bad file descriptor')
> 
> On the console we see:
> (XEN) (file=/build/kmacy/xen/xen-unstable.hg/xen/include/asm/mm.h,
> line=187) Error pfn be9: rd=ffbf8a80, od=ffbf8a80, caf=00000000,
> taf=f0000001
> (XEN) (file=/build/kmacy/xen/xen-unstable.hg/xen/include/asm/mm.h,
> line=187) Error pfn 10dcb: rd=ffbf8a80, od=00000000, caf=00000000,
> taf=f0000000
> [ERR] corruptxenstored corruption: connection id 0: err Bad address:
> Unknown error 14 (Bad address)
> 
> *NOW* comes the fun part:
> [root@rs0 ~]# /sbin/shutdown -r now
> 
> Broadcast message from root (pts/1) (Wed Jul  6 11:01:00 2005):
> 
> The system is going down for reboot NOW!
> INIT: Sending processes the TERM signal
> (XEN) CPU:    0
> (XEN) EIP:    e008:[<ff10b882>]
> (XEN) EFLAGS: 00210202   CONTEXT: hypervisor
> (XEN) eax: 0000000a   ebx: 00000000   ecx: 00000000   edx: 00000003
> (XEN) esi: 00000001   edi: ffbf2700   ebp: ffbf1004   esp: ff103e04
> (XEN) cr0: 8005003b   cr3: 181cd000
> (XEN) ds: e010   es: e010   fs: 0000   gs: 0000   ss: e010   cs: e008
> (XEN) Xen stack trace from esp=ff103e04:
> (XEN)    00000001 00000052 00000000 00000400 fec6b000 ff1a9900 fc400000 
> 00000f00
> (XEN)    00000000 00000000 00000001 000a0067 fc400f00 ff1a9900
> ff1a7080 [ff1269de]
> (XEN)    ff1a7080 ff1a9900 000000a0 00000000 fec6b000 32ff0001 ff1a9900 
> 0000067c
> (XEN)    00000261 000a0067 fec72000 [ff12a110] 000a0067 ff1a9900
> 00000000 [ff13b9ef]
> (XEN)    181cd000 ff103fb4 00000001 c7910985 ff1a9b80 fec72000
> ff1a9900 [ff12a266]
> (XEN)    ff1a9900 fec72000 ff1b2000 [ff12ba14] fec71000 ff1a9b80
> ff103fb4 ff1a9b90
> (XEN)    c7910985 fe31e440 00000000 00000000 00000000 00000000
> ff1a9900 [ff12d55e]
> (XEN)    ff1a9900 00000000 0000000c 00200286 ff103fb4 ff1a9900
> [ff13b9ef] 181cd000
> (XEN)    001446c9 00000000 c7910984 ff1a9900 00018ef0 18ef0061
> [ff12eb6a] 00018ef0
> (XEN)    ffffffff 00000010 ff1a9900 00000007 c873e000 00010000 c0568ee0 
> 000002db
> (XEN)    32db0001 ff103fb4 ff1a9b80 ff1a9900 00000000 fe3f8b6c ff1a9900 
> ff103fb4
> (XEN)    c7910984 ffbf3080 [ff13e867] 00000000 00000000 00000000
> 00000000 00000001
> (XEN)    00000005 00000020 ee000000 ffbf3080 ffbf3bf8 ffbf3080 ffbf3080 
> ffbf3080
> (XEN)    00007ff0 c8623284 b6e69000 [ff14a8f3] c8683eec 00000001
> 00000000 00007ff0
> (XEN)    c8623284 b6e69000 0000001a 000e0003 c0115b33 00000061 00200282 
> c8683eec
> (XEN)    00000069 0000007b 0000007b 00000000 00000000 00000000 ffbf3080
> (XEN) Xen call trace from esp=ff103e04:
> (XEN)    [<ff1269de>] [<ff12a110>] [<ff13b9ef>] [<ff12a266>]
> [<ff12ba14>] [<ff12d55e>]
> (XEN)    [<ff13b9ef>] [<ff12eb6a>] [<ff13e867>] [<ff14a8f3>]
> 
> ****************************************
> Panic on CPU0:
> CPU0 FATAL PAGE FAULT
> [error_code=0000]
> Faulting linear address: 00000004
> ****************************************
> 
> Reboot in five seconds...
> 
> 
> Line 910 of "grant_table.c" starts at address 0xff10b87f
> <gnttab_check_unmap+175>
>    and ends at 0xff10b888 <gnttab_check_unmap+184>.
> <...>
>              ( readonly ? 1 : (!(map->ref_and_flags & GNTMAP_readonly))))
>         {
>             ref = (map->ref_and_flags >> MAPTRACK_REF_SHIFT);
>             act = &rgt->active[ref];      <- line 910
> 
>             spin_lock(&rgt->lock);
> 
>             if ( act->frame != frame )
> <...>
> 0xff10b882 <gnttab_check_unmap+178>:    mov    0x4(%ecx),%eax
> 0xff1269de <put_page_from_l1e+270>:     test   %eax,%eax
> 0xff12a110 <revalidate_l1+176>: jmp    0xff12a090 <revalidate_l1+48>
> 0xff13b9ef <__flush_tlb_mask+239>:      mov    0x44(%ebx),%eax
> 0xff12a266 <ptwr_flush+246>:    mov    %edi,(%esp)
> 0xff12d55e <do_mmuext_op+1150>: jmp    0xff12d17a <do_mmuext_op+154>
> 0xff13b9ef <__flush_tlb_mask+239>:      mov    0x44(%ebx),%eax
> 0xff12eb6a <ptwr_do_page_fault+506>:    mov    %eax,%esi
> 0xff13e867 <do_page_fault+423>: test   %eax,%eax
> 0xff14a8f3 <hypercall+83>:      mov    %eax,0x18(%esp)
>

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