On Wed, Apr 30, 2008 at 6:43 PM, Dave Anderson <anderson(a)redhat.com> wrote:
 Mike Snitzer wrote:
 > Hi,
 >
 > I searched the archives and found that you've discussed an issue I'm
 > seeing with x86_64 kernels where crash doesn't have line numbers for
 > modules' symbols:
 > 
https://www.redhat.com/archives/crash-utility/2008-January/msg00021.html
 >
 > I'm using crash-4.0-6.3 on a RHEL5U1 x86_64 system with a custom
 > 2.6.22.19 kernel.  Given that the RHEL5U1 x86_64 kernels clearly do
 > provide accurate line numbers for modules, has anyone identified how
 > that is?  I have to believe the redhat kernel is patched to fix this
 > issue.
 >
 > I looked over the various redhat patches that are applied to RHEL5's
 > 2.6.18 sources but can't see a patch that stands out as specifically
 > addressing this x86_64 issue.  But I could easily be overlooking some
 > patch.
 >
 > please advise, thanks.
 > Mike
 >
 > ps. please cc me as I've not yet been able to join the list
 >
 >
  You're on the list now...
  Anyway, there are no kernel patches applied to RHEL5 kernels
  to make it work that I'm aware of.  That being said, I don't
  have an answer as to why they don't work for modules on your
  custom kernel (or why they don't work in RHEL4 kernels...). 
I configured my x86_64 kernel to be relocatable.  Could this be the
reason for modules' line number debug data being off?  From:
http://people.redhat.com/anderson/crash.changelog.html#4_0_4_5
"Using /proc/kallsyms or a --reloc=[size] as a command line argument
 is similar to using a System.map file, in that it results in the loss
 of the use of line number debug data."
Still doesn't explain why RHEL4 isn't happy in this regard either...
I'm trying a non-relocatable variant of my kernel now and will report
back with the results.
Mike