Guy Streeter wrote:
On Tue, 2007-05-29 at 15:45 -0400, David Anderson wrote:
Alex Sidorenko wrote:
Hi Dave,
when I try to use 'vtop' for process pages on 2.6.20 kernel (Ubuntu/Feisty) on
x86 architecture, I get error messages about page table. The easiest way to
reproduce is to run 'ps -a' on a live kernel:
PID: 0 TASK: c03a2440 CPU: 0 COMMAND: "swapper"
ps: no user stack
PID: 0 TASK: df838560 CPU: 1 COMMAND: "swapper"
ps: no user stack
PID: 1 TASK: df838a90 CPU: 1 COMMAND: "init"
ps: read error: physical address: 7f2f0000 type: "page table"
Running crash with -d8:
PID: 1 TASK: df838a90 CPU: 1 COMMAND: "init"
<readmem: df838a90, KVADDR, "fill_task_struct", 1328, (ROE|Q), 8d2eac0>
<readmem: dfb71e40, KVADDR, "fill_mm_struct", 432, (ROE|Q), 8d8bf80>
GETBUF(128 -> 1)
FREEBUF(1)
GETBUF(128 -> 1)
FREEBUF(1)
GETBUF(128 -> 1)
FREEBUF(1)
GETBUF(128 -> 1)
FREEBUF(1)
arg_start: bf991ecf arg_end: bf991ee1 (18)
env_start: bf991ee1 env_end: bf991ff1 (272)
GETBUF(291 -> 1)
<readmem: dfb6f000, KVADDR, "pgd page", 4096, (FOE), 843cf90>
<readmem: dfb6f000, KVADDR, "pmd page", 4096, (FOE), 843cf90>
<readmem: 7f2f0000, PHYSADDR, "page table", 4096, (FOE), 843efa0>
ps: read error: physical address: 7f2f0000 type: "page table"
The same crash-4.0-4.1 works fine on live 2.6.15 kernel. Did the page table
layout change between 2.6.15 and 2.6.20 ?
Regards,
Alex
I don't know. I don't have an x86 2.6.20 live system or dumpfile
readily available,
so I'll need some help from the "outside world" here...
Anybody else know anything about this?
On a 2.6.21 kernel with the -rt patchset, and crash-4.0-4.1, I see some
of this:
PID: 3093 TASK: f69793b0 CPU: 0 COMMAND: "mingetty"
ps: cannot access user stack address: bf9fdf4c
PID: 3094 TASK: f7f2abf0 CPU: 0 COMMAND: "mingetty"
ps: cannot access user stack address: bfbb2f4c
on i686 but I haven't seen it on x86_64.
(Dave, I have these kernels, and systems with these kernels, you can
access if you wish)
--Guy
Ok -- tomorrow I'll request an RHTS RHEL5 i386 machine, and may come back to
you for the -rt kernel src.rpm.
In the meantime, if anybody else out there has any insight into any
recent changes
in this area, please post your thoughts here...
Thanks,
Dave
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