Re: [linux-lvm] pvmove hangs

[Jan Niehusmann <list039@gondor.com>]

On Mon, Aug 18, 2003 at 03:12:29PM +0100, Alasdair G Kergon wrote:
> On Mon, Aug 18, 2003 at 01:14:15AM +0200, Jan Niehusmann wrote:
> > I noticed the WCHAN fields in my ps output were not very useful, because
> > they pointed to a module and were not decoded.
> 
> Does your System.map file correspond to the running kernel?
> [See ps man page / strace to check where it's getting that file from]

Sure it is :-)
(I use debian make-kpkg to build a kernel .deb, which makes sure that
the right System.map file gets installed together with the kernel)

But it doesn't contain symbols which get defined by modules. And
even /proc/ksymoops only contains exported symbols, which daemon()
from dm-daemon.c is not. So I looked at the next exported symbol
(dm_daemon_start), took the difference between these two addresses,
and went back the number of bytes in objdump --disassemble, and compared
that to the sourcecode to find the actual positions.

Even though I don't know x86 assembly too well, it was not difficult to
match assembly instructions to C source code, as the source at this
position is quite low-level.

Jan