Re: [Libunwind-devel] libunwind with LD_PRELOAD option

[Arun Sharma]

On Tue, Sep 6, 2011 at 8:44 AM, Shan Shan
<address@hidden> wrote:

> Thanks. Here is the output of target's libc and libdl libraries. .eh_frame
> seems to be only 4 bytes in both the libraries and i don't see debug frames.
> When i checked the unwind code, it tries some 4 options to unwind a stack
> and one of the options look for .extab, .exidx frames too. May be it's
> picking up from there? May be that's why it's working for a simple
> application compiled with default gcc options.

Those are ARM specific unwind mechanisms. On x64, we just use dwarf +
.eh_frame. Ken seems to have a wiki on some of these topics:

https://wiki.linaro.org/KenWerner/Sandbox/libunwind

> Still, I am not sure how those 3 symbols alone causes crash even when not
> called. Those names doesn't look like one colliding with global namespace?

Even when you don't invoke any APIs there may be some static
initializers in the library that executed. Or it could be some random
limit on code or data segment that was exceeded by linking the
library. The best option is to gdb + symbols working for your
environment. Hopefully one of the ARM experts reading the list will
help you out.

 -Arun