I've been trying to debug a segmentation fault recently using valgrind on my raspberry Pi (model b), running Debian GNU/Linux7.0 (wheezy). Every time I run valgrind on a compiled C++ program, I get something like the following:
disInstr(arm): unhandled instruction: 0xF1010200
cond=15(0xF) 27:20=16(0x10) 4:4=0 3:0=0(0x0)
valgrind: Unrecognized instruction at address 0x4843638.
at 0x4843638: ??? (in /usr/lib/arm-linux-gnueabihf/libconfi_rpi.so)
#include <iostream>
using namespace std;
int main() {
cout<<"Hello World"<<endl;
return 0;
}
valgrind ./a.out
From your code (a simple hello world), It complain about an Unrecognized instruction at address 0x4843638
. My guess is:
EDIT :
http://valgrind.org/docs/manual/faq.html
3.3. My program dies, printing a message like this along the way:
vex x86->IR: unhandled instruction bytes: 0x66 0xF 0x2E 0x5
One possibility is that your program has a bug and erroneously jumps to a non-code address, in which case you'll get a SIGILL signal. Memcheck may issue a warning just before this happens, but it might not if the jump happens to land in addressable memory.
Another possibility is that Valgrind does not handle the instruction. If you are using an older Valgrind, a newer version might handle the instruction. However, all instruction sets have some obscure, rarely used instructions. Also, on amd64 there are an almost limitless number of combinations of redundant instruction prefixes, many of them undocumented but accepted by CPUs. So Valgrind will still have decoding failures from time to time. If this happens, please file a bug report.
EDIT2 :
From wikipedia, the Raspberry Pi CPU:
2.11. Limitations
On ARM, essentially the entire ARMv7-A instruction set is supported, in both ARM and Thumb mode. ThumbEE and Jazelle are not supported. NEON, VFPv3 and ARMv6 media support is fairly complete.
Your program/library just happened to have some instruction which is not supported yet.