[Ltrace-devel] ltrace v0.7.0-git: Session on a Freetz MIPSEL router box
Petr Machata
pmachata at redhat.com
Mon Oct 8 09:12:30 UTC 2012
"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
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