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Description of problem:
[ben@ulna2:~]$ readelf --unwind /usr/lib64/libm.so
The decoding of unwind sections for machine type AArch64 is not currently supported.
Version-Release number of selected component (if applicable):
binutils-2.27-28.base.el7_5.1.aarch64
How reproducible:
always
Steps to Reproduce:
see above.
Actual results:
The decoding of unwind sections for machine type AArch64 is not currently supported.
Expected results:
a dump of the .eh_frame section.
Additional info:
http://post-office.corp.redhat.com/archives/tools/2016-August/msg00054.html
May be slightly related to: https://bugzilla.redhat.com/enter_bug.cgi?product=Red%20Hat%20Enterprise%20Linux%207
Whoa this isn't just ARM evidently we can't process x86_64 either
[ben@Mustang ~]$ readelf -u /usr/lib64/libm.so.6
The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.
I thought it was just an ARM thing.
[ben@Mustang ~]$ rpm -q binutils
binutils-2.29.1-23.fc28.x86_64
Useful information on how to read the .eh_frame section:
https://www.airs.com/blog/archives/460
Maybe the best plan is to extend readelf to process the .eh_frame sections for unwind info.
A workaround is readelf -wF or -wf however, it is unclear to me why -u isn't wired up to do the same thing as -wf. Is that something worth considering?
Hi Ben,
Would you be terribly upset if I delayed this bug to say RHEL 7.7 ?
It is a new feature request and I would prefer to have the feature
implemented upstream first and then backported once it has been
tested a bit...
Cheers
Nick
(In reply to Nick Clifton from comment #6)
> Hi Ben,
>
> Would you be terribly upset if I delayed this bug to say RHEL 7.7 ?
For this one — not a problem.
>
> It is a new feature request and I would prefer to have the feature
> implemented upstream first and then backported once it has been
> tested a bit...
>
> Cheers
> Nick
The reason for this bug is that there is evidently a problem with the AARCH64 unwind information in some cases and the information doesn't match the .eh_frame debug data. I was hoping to use this feature to help debug the problem. I was unable to spot the problem when I was doing some testing and so the customer promised me a reproducer but got tied up with other problems. So the original problem report is on hold for the time being.
Even having a prototype decoder would be helpful when this problem report pops back up again.