Forgot to compile with unwind information: -funwind-tables
D'oh On 25 June 2013 12:00, Atish Nazir <[email protected]> wrote: > Hi guys, > I'm looking at using libunwind to work around the perennial lack of > backtrace on uclibc MIPS. To test it out on the embedded system in > question I knocked together a simple application consisting of a couple of > recursive functions before calling the show_backtrace example code featured > on the website documentation. > > Unfortunately the show_backtrace is unable to show anything useful, > unw_step exits with -UNW_ENOINFO. Cranking up the debug levels gives me > the following (the full code attached): > > Backtracing 00400b10 > >_ULmips_init_local: (cursor=0x7fe1a668) > >_ULmips_step: (cursor=0x7fe1a668) > >get_rs_cache: acquiring lock > >_ULmips_dwarf_find_proc_info: looking for IP=0x400927 > >_ULmips_dwarf_callback: checking ./main, base=0x0) > >_ULmips_dwarf_callback: checking ../lib//libunwind.so.8, > base=0x770cd000) > >_ULmips_dwarf_callback: checking > ../lib//libunwind-mips.so.8, base=0x77045000) > >_ULmips_dwarf_callback: checking /lib/libgcc_s.so.1, > base=0x7700e000) > >_ULmips_dwarf_callback: checking /lib/libc.so.0, > base=0x76f54000) > >_ULmips_dwarf_callback: checking /lib/ld-uClibc.so.0, > base=0x77142000) > >_ULmips_dwarf_find_proc_info: IP=0x400927 not found > >put_rs_cache: unmasking signals/interrupts and releasing > lock > >_ULmips_dwarf_step: returning -10 > > > "Backtracing" is the result of a __builtin_return_address(0) and is > correct from my examination of the disassembly. > > Other than it not working. What really concerns me is the value for IP > being unaligned to a word boundary and that it doesn't correspond to an > actual instruction (I performed a objdump -d on the executable and crossed > referenced against the proc/maps file to sanity check). > > Compiler: mipsel-linux-gcc (Broadcom stbgcc-4.5.3-2.4) 4.5.3 > uclibc: uClibc-0.9.32 > > Compile line: mipsel-linux-uclibc-gcc -g -fPIC -Ilibunwind/include > -Llibunwind/src/.libs -lunwind -lunwind-mips -Wall -W -D_REENTRANT -fPIE > -O0 -fno-inline -fno-omit-frame-pointer -o main main.c > > > > Thanks in advance. > > >
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