Re: 2.6.25-rc1 xen pvops regression

From: Jeremy Fitzhardinge
Date: Sun Feb 17 2008 - 07:11:30 EST


Joel Becker wrote:
Unfortunately that doesn't narrow down what the kernel was actually trying to do at the time. Clearly a set_pte; looks like someone is trying to create a writable mapping of an existing pte page.

Does "console=hvc0 earlyprintk=xen" on the kernel command line give any clue about how far it gets before crashing?


I built a kernel using your .config here, but I can't reproduce the problem. It makes it all the way to trying to start init (failed at that point because I didn't create an initrd with the xvd module to mount /).

Console is already hvc0, but earlyprintk gets us:

--8<-----------------------------------------------------------------
Reserving virtual address space above 0xf57fe000
Linux version 2.6.25-rc2-bisectme (jlbec@xxxxxxxxxxxxxxxxxxxxxxxx) (gcc
version 4.1.2 20070626 (Red Hat 4.1.2-14)) #21 SMP Fri Feb 15 16:28:35
PST 2008
ACPI in unprivileged domain disabled
BIOS-provided physical RAM map:
Xen: 0000000000000000 - 0000000078000000 (usable)
console [xenboot0] enabled
1192MB HIGHMEM available.
727MB LOWMEM available.
Started domain ca-test58
Scan SMP from c0000000 for 1024 bytes.
Scan SMP from c009fc00 for 1024 bytes.
Scan SMP from c00f0000 for 65536 bytes.
NX (Execute Disable) protection: active
Zone PFN ranges:
DMA 0 -> 4096
Normal 4096 -> 186366
HighMem 186366 -> 491520
Movable zone start PFN for each node
early_node_map[1] active PFN ranges
0: 0 -> 491520
-->8-----------------------------------------------------------------

That's it.

I get:

Entering add_active_range(0, 0, 16384) 0 entries of 256 used
Zone PFN ranges:
DMA 0 -> 4096
Normal 4096 -> 16384
HighMem 16384 -> 16384
Movable zone start PFN for each node
early_node_map[1] active PFN ranges
0: 0 -> 16384
On node 0 totalpages: 16384
DMA zone: 32 pages used for memmap
DMA zone: 0 pages reserved
DMA zone: 4064 pages, LIFO batch:0
Normal zone: 96 pages used for memmap
Normal zone: 12192 pages, LIFO batch:1
HighMem zone: 0 pages used for memmap
Movable zone: 0 pages used for memmap
...


What happens if you give the domain less memory?

J
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