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Re: [Xen-devel] Reproducible system crash

On Wednesday 16 March 2005 18:55, Keir wrote:
> ... Here's a slightly harder thing to try:
> 1. Edit linux/include/asm-xen/asm-i386/pgtable-2level.h, and change
> set_pte_batched() to use xen_l1_pgentry_update rather than
> queue_l1_pgentry_update. Also, kill current definition of set_pte() and
> redefine it to the same as the new set_pte_batched().
s/pgentry/entry/ in the above? -- That's what I've used.

> 2. Edit xen/arch/x86/memory.c, at the test that fails for you ('Bad L1
> type'). In the error path, before returning 0, add:
>      extern void show_guest_stack(void);
>      show_guest_stack();
I left out the definition, it was somewhere else.

> This should cause us to get a backtrace of the guest kernel state when
> the bad PTE is written. If you send a link to that along with your
> vmlinux file then we can work out where the _PAGE_GLOBAL bit is coming
> from.
You can temporarily get the vmlinux from <http://joanes.net/vmlinux>. The 
output contains just a couple of extra lines:

open("/usr/lib/wine/apphelp.dll.so", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No 
suchfile or directory)
rt_sigprocmask(SIG_BLOCK, NULL, [RTMIN], 8) = 0
(XEN) (file=extable.c, line=71) Pre-exception: fc530abe -> fc530b74
(XEN) DOM0: (file=memory.c, line=409) Bad L1 type settings 0100
(XEN) Guest EIP is c0109904
(XEN) DOM0: (file=memory.c, line=1760) ptwr: Could not re-validate l1 page
(XEN) BUG at domain.c:143
(XEN) CPU:    0
(XEN) EIP:    0808:[<fc505e0e>]
(XEN) EFLAGS: 00011292
(XEN) eax: 00000000   ebx: fcff99e0   ecx: 00000000   edx: 00000000
(XEN) esi: 00000010   edi: ff951000   ebp: 00000010   esp: fc503e84
(XEN) ds: 0810   es: 0810   fs: 0810   gs: 0810   ss: 0810
(XEN) Stack trace from ESP=fc503e84:
(XEN) fc532408 fc5324a7 0000008f 00000000 fcff0000 00000000 00000010 
(XEN)        ff950000 00000000 000006e0 [fc5227ac] 00000000 c0386f08 00000008 
(XEN)        ff913448 00000010 fcff0010 00000004 00000ff0 e0000000 fcff99e0 
(XEN)        fcff9a54 00000010 00000008 fcff99e0 00000000 ff950000 00000000 
(XEN)        fef390a8 00000001 c0109929 0c3d6061 00001096 0030b033 0c3d6061 
(XEN)        00000010 00000000 0000c3d7 [fc52395d] 00000001 fc503f6c 00000000 
(XEN)        [fc518117] 2d47dca4 0000003e 000002e0 00000010 0c3d7061 05c00000 
(XEN)        00000001 feffbb80 0c3d6063 fcff99e0 ce429ffc fc503fb8 ce521ff9 
(XEN)        ce429ffc 00000000 c010a960 77acdfa0 [fc511972] 000e0003 0000a960 
(XEN)        ffffffff c010a960 77acdfa0 [fc530c4e] fc503fb8 77ef5ca4 0000007b 
(XEN)        ffffffff c010a960 77acdfa0 00000000 000e0003 c0109904 00000061 
(XEN)        ce42a000 00000069 0000007b 0000007b 0000003b 00000033 fcff99e0
(XEN) Call Trace from ESP=fc503e84: [<fc521b86>] [<fc5227ac>] [<fc52395d>] 
[<fc518117>] [<fc52c578>] [<fc511972>]
(XEN)    [<fc530c4e>]

CPU0 FATAL TRAP: vector = 6 (invalid operand)
Aieee! CPU0 is toast...

Reboot in five seconds...

-       Peter.

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