Re: [Libunwind-devel] SIGSEGV Segmentation Fault in access_mem

[Milian Wolff]

On Dienstag, 20. Juni 2017 16:15:14 CEST Ali Nakipoglu wrote:
> Hi,
> 
> Hope everyone very well.
> 
> Im working on a memory tracking tool that gets linked at run-time via
> LD_PRELOAD.

I can't help you with the actual bug as I haven't encountered it myself. But 
the above sounds very much like my heaptrack tool:

https://github.com/KDE/heaptrack

May I invite you to collaborate?

Cheers

> It's using libunwind to get stack trace information. With
> most of the test applications its working fine but, there is one that
> libunwind always crashes with the stack trace:
> 
> #0  0x00007ffff7bbfe74 in access_mem () from /build-debug/Intercept.so
> #1  0x00007ffff7bbf724 in _Ux86_64_step () from /build-debug/Intercept.so
> #2  0x00007ffff7bbc2b8 in Intercept::trace() () at
> /src/Intercept/Intercept.cpp:185
> #3  0x00007ffff7bbc4c3 in calloc () at src/Intercept/Intercept.cpp:252
> #4  0x00007fffe35f1b33 in ?? () from /usr/lib64/nvidia/libGL.so.1
> #5  0x00007fffcb50302e in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> #6  0x00007fffcb50c11b in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> #7  0x00007fffcb50d1b8 in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> #8  0x00007fffcb510c63 in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> #9  0x00007fffcb6686f3 in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> #10 0x00007fffcb63be54 in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> #11 0x00007fffcb63d647 in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> #12 0x00007fffcb655f24 in ?? () from
> /usr/lib64/nvidia/libnvidia-glcore.so.375.39
> 
> Libunwind 1.2.1.
> 
> Is there a way to bypass it or its is a bug? Can CONSERVATIVE_CHECKS
> (https://github.com/pathscale/libunwind/blob/1fcbfc649837d2a28e1901986437ca6
> bf9c4f4d4/src/x86_64/Gstep.c#L61) build flag solve this?
> 
> Many thanks,
> 
> Ali
> 
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-- 
Milian Wolff
address@hidden
http://milianw.de