[Ltrace-devel] ltrace v0.7.0-git: Session on a Freetz MIPSEL router box

[Petr Machata]

"Jackie Yeh [葉龍泉]" <jackieontravel at gmail.com> writes:

> Hi Petr,
>
> I applied your patch, and attached the log with -D77 option.
>
> :: fetch_rd32: couldn't read 20 bytes from (nil)
> It's strange that 'addr' is a NULL pointer!

Indeed.  It loads 0 from DT_DEBUG.  What libc are you using?  It seems
like uClibc doesn't set DT_DEBUG so as not to dirty pages.

Several backup plans are possible: we could look for _r_debug (which
seems to be named _dl_debug_addr in uClibc land) in the binary of
dynamic linker.  Failing that, the brute force solution is to watch mmap
ad munmap system calls and re-parse /proc/pid/maps on any of these.

Thanks,
PM