Tuesday, September 08, 2015
I don't think anybody actually uses this instruction
Odd.
The runtime code for DynASM looks a bit … odd, and I was curious what Valgrind had to say about it.
[spc]lucy:~/source/jit>valgrind ./calc ==15664== Memcheck, a memory error detector. ==15664== Copyright (C) 2002-2005, and GNU GPL'd, by Julian Seward et al. ==15664== Using LibVEX rev 1575, a library for dynamic binary translation. ==15664== Copyright (C) 2004-2005, and GNU GPL'd, by OpenWorks LLP. ==15664== Using valgrind-3.1.1, a dynamic binary instrumentation framework. ==15664== Copyright (C) 2000-2005, and GNU GPL'd, by Julian Seward et al. ==15664== For more details, rerun with: -v ==15664== x = 1 - 0 vex x86->IR: unhandled instruction bytes: 0xCE 0x66 0xA3 0xCE ==15664== Your program just tried to execute an instruction that Valgrind ==15664== did not recognise. There are two possible reasons for this. ==15664== 1. Your program has a bug and erroneously jumped to a non-code ==15664== location. If you are running Memcheck and you just saw a ==15664== warning about a bad jump, it's probably your program's fault. ==15664== 2. The instruction is legitimate but Valgrind doesn't handle it, ==15664== i.e. it's Valgrind's fault. If you think this is the case or ==15664== you are not sure, please let us know. ==15664== Either way, Valgrind will now raise a SIGILL signal which will ==15664== probably kill your program. ==15664== Use of uninitialised value of size 4 ==15664== at 0xBC945C: _itoa_word (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBCCA09: vfprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBE5ACA: vsprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBD2DEA: sprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0x804ACA3: crashreport_hexdump (crashreport.c:154) ==15664== by 0x804B2BD: crashreport_handler (crashreport.c:388) ==15664== by 0xBB79AF: (within /lib/tls/libc-2.3.4.so) ==15664== by 0x804A9DD: main (calc.dasc:472) ==15664== ==15664== Conditional jump or move depends on uninitialised value(s) ==15664== at 0xBC9462: _itoa_word (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBCCA09: vfprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBE5ACA: vsprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBD2DEA: sprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0x804ACA3: crashreport_hexdump (crashreport.c:154) ==15664== by 0x804B2BD: crashreport_handler (crashreport.c:388) ==15664== by 0xBB79AF: (within /lib/tls/libc-2.3.4.so) ==15664== by 0x804A9DD: main (calc.dasc:472) ==15664== ==15664== Use of uninitialised value of size 4 ==15664== at 0xBC9474: _itoa_word (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBCCA09: vfprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBE5ACA: vsprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0xBD2DEA: sprintf (in /lib/tls/libc-2.3.4.so) ==15664== by 0x804ACA3: crashreport_hexdump (crashreport.c:154) ==15664== by 0x804B2BD: crashreport_handler (crashreport.c:388) ==15664== by 0xBB79AF: (within /lib/tls/libc-2.3.4.so) ==15664== by 0x804A9DD: main (calc.dasc:472) ==15664== ==15664== Use of uninitialised value of size 4 ==15664== at 0x804ACC0: crashreport_hexdump (crashreport.c:155) ==15664== by 0x804B2BD: crashreport_handler (crashreport.c:388) ==15664== by 0xBB79AF: (within /lib/tls/libc-2.3.4.so) ==15664== by 0x804A9DD: main (calc.dasc:472) not in syscall (0xB0044ADC - 0xB0044B31) valgrind: m_syswrap/syswrap-main.c:606 (vgPlain_client_syscall): Assertion 'sci->status.what == SsIdle' failed. ==15664== at 0xB000E029: report_and_quit (m_libcassert.c:122) ==15664== by 0xB000E1C2: vgPlain_assert_fail (m_libcassert.c:185) ==15664== by 0xB003AEA6: vgPlain_client_syscall (syswrap-main.c:606) ==15664== by 0xB002C826: handle_syscall (scheduler.c:623) ==15664== by 0xB002CAED: vgPlain_scheduler (scheduler.c:726) ==15664== by 0xB0014568: final_tidyup (m_main.c:2716) ==15664== by 0xB00141C9: shutdown_actions_NORETURN (m_main.c:2578) ==15664== by 0xB003C2D5: run_a_thread_NORETURN (syswrap-linux.c:139) sched status: running_tid=1 Thread 1: status = VgTs_Runnable ==15664== at 0xD080B5: pthread_once (in /lib/tls/libpthread-2.3.4.so) ==15664== by 0xC9BB76: free_mem (in /lib/tls/libc-2.3.4.so) ==15664== by 0xC9B811: __libc_freeres (in /lib/tls/libc-2.3.4.so) ==15664== by 0x4000336: _vgw_freeres (vg_preloaded.c:62) ==15664== by 0xBB78C4: raise (in /lib/tls/libc-2.3.4.so) ==15664== by 0x804B3E7: crashreport_handler (crashreport.c:495) ==15664== by 0xBB79AF: (within /lib/tls/libc-2.3.4.so) ==15664== by 0x804A9DD: main (calc.dasc:472) Note: see also the FAQ.txt in the source distribution. It contains workarounds to several common problems. If that doesn't help, please report this bug to: www.valgrind.org In the bug report, send all the above text, the valgrind version, and what Linux distro you are using. Thanks. [spc]lucy:~/source/jit>
Really Valgrind?
You don't support the INTO opcode?
Wow …
