Blair Barnett writes: > Hi Andrew, > > So our experiment with the 4.1.1 EABI compiler along with your patch provided no new results. > > I applied your patch and recompiled arm-linux-gcc and recompiled our little test program. I copied the program to our arm device and ran it, obtaining the following output: > > arm-linux-gcc -o fault-unwind fault.c > > ./fault-unwind > in routine1 at 0x00008874 > in routine2 at 0x0000882c > in routine3 at 0x000087e4 > in routine4 at 0x00008794 > in catch_segfault > Obtained 1 stack frames. > /lib/ld-linux.so.2 [0x40012f84] > Segmentation fault That's what I predicted, right? > > > If we run the 4.1.2 compiler included with ubuntu on our little test program, we get the following results: > > bbarnett@kitt:~$ gcc -v > Using built-in specs. > Target: i486-linux-gnu > Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --enable-checking=release i486-linux-gnu > Thread model: posix > gcc version 4.1.2 (Ubuntu 4.1.2-0ubuntu4) > bbarnett@kitt:~$ gcc -o fault fault.c > bbarnett@kitt:~$ ./fault > in routine1 at 0x080486de > in routine2 at 0x080486ae > in routine3 at 0x0804867e > in routine4 at 0x0804864a > in catch_segfault > Obtained 8 stack frames. > ./fault [0x8048547] > [0xffffe420] > ./fault [0x80486ac] > ./fault [0x80486dc] > ./fault [0x804870c] > ./fault [0x8048730] > /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xdc) [0xb7e5febc] > ./fault [0x8048491] > Segmentation fault (core dumped) > > So glibc backtrace() appears to work in an EABI environment, just not an ARM EABI environment. Sure, because ARM doesn't have fallback_frame_state_for, like I said. x86 does. Remember what I advised you to do: -------------------------------------------------------------------- The SIGCONTEXT ctx that's passed to your segfault handler contains the registers at the point the segfault occurred, and you can unwind starting from there. Don't do this: void *fp = __builtin_frame_address (0); Instead, pull fp and sp out of the SIGCONTEXT ctx. -------------------------------------------------------------------- Andrew.
