Mike Snitzer wrote:
On Wed, Apr 30, 2008 at 6:43 PM, Dave Anderson <anderson@xxxxxxxxxx> 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."
No, that particular issue only applies to the base kernel, and is
irrelevant with respect to modules.
(Note that the RHEL5 kernel is relocatable as well.)
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.
What you might confirm is whether you're getting any debuginfo data when
you load
the module? Are you sure that your modules are being built with -g?
Dave
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