Re: [Crash-utility] kmem -[sS] segfault on 2.6.25.17
----- "Mike Snitzer" <snitzer(a)gmail.com> wrote:
On Thu, Oct 16, 2008 at 1:16 PM, Dave Anderson
<anderson(a)redhat.com>
wrote:
>
> ----- "Dave Anderson" <anderson(a)redhat.com> wrote:
>> Ok, then I can't see off-hand why it would segfault. Prior to
this
>> routine running, si->cpudata[0...i] all get allocated buffers
equal
>> to the size that's being BZERO'd.
>>
>> Is si->cpudata[i] NULL or something?
(gdb) p si->cpudata
$1 = {0xa56400, 0xa56800, 0xa56c00, 0xa57000, 0x0 <repeats 252
times>}
(gdb) p si->cpudata[0]
$4 = (ulong *) 0xa56400
OK, so if "i" is 0 at the time, then I don't understand how the
BZERO/memset can segfault while zero'ing out memory starting at
address 0xa56400?
BZERO(si->cpudata[i], sizeof(ulong) * vt->kmem_max_limit);
Even if it over-ran the 0x400 bytes that's been allocated to
si->cpuinfo[0], it would still harmlessly run into the buffer
that was allocated for si->cpuinfo[1]. What's the bad address
it's faulting on?
And for sanity's sake, what is the crash utility's vm_table.kmem_max_limit
equal to, and what architecture are you running on?
> Also, can you confirm that you are always using the exact vmlinux
> that is associated with each vmcore/live-system? I mean you're
> not using a System.map command line argument, right?
Yes, I'm using the exact vmlinux. Not using any arguments for live
crash; I am for the vmcore runs but that seems needed given crash's
[mapfile] [namelist] [dumpfile] argument parsing.
I use a redhat-style kernel rpm build process (with a more advanced
kernel .spec file); so I have debuginfo packages to match all my
kernels.
OK cool -- so you know what you're doing. ;-)
BTW, if need be, would you be able to make the vmlinux/vmcore pair
available for download somewhere? (You can contact me off-list with
the particulars...)
Dave