On 27/01/2026 20:17, Paul Floyd via Valgrind-users wrote:
On 27/01/2026 01:06, Steve Edmonds wrote:
Hi. I have just joined the group to see if I can resolve a long
standing issue with valgrind on Opensuse.
I have been using some accounting software for many years, initially
it ran fine and then at some point it started causing a segmentation
fault.
I then started using it with valgrind, successful with some versions
of valgrind and not with others, when it fails I get the following
before termination and core dump.
==199084== Illegal opcode at address 0x453BC82
==199084== at 0x453BC82: write_vec (xcb_conn.c:262)
Using valgrind from the latest Leap 15.6 and 16.0 repositories fails
(valgrind-3.26.0-355.d_t.2.x86_64.rpm, 3.24.0-150600.3.3.1,
3.22.0-150600.1.3, 3.24.0-160000.2.2 and 3.25.1-160000.1.1) I do have
the software running successfully with versions 3.25.1-350.d_t.1 (on
Leap 15.6) and 3.13.0-lp150.4.61-x86_64 (on Leap 15.0 in a VM). I am
trying to get to grips with what might determine a successful version
of valgrind, I can no longer locate the rpm for 3.25.1-350.d_t.1 to
try on Leap 16.0 and quite happy to build from source if there is
some configuration in the source that will resolve this issue.
Hi Steve
Trying older Valgrind versions is unlikely solve the problem.
What application are you trying to run under Valgrind? I just tried
Valgrind 3.25.1 on openSUSE LEAP 16.0 running kwrite and there were no
major issues.
In gdb (with kwrite again) that piece of code looks like
261 n = *count;
262 if (n > IOV_MAX)
263 n = IOV_MAX;
Nothing unusual in the assembler, like like it is using SSE instructions.
Can you also post the op-code bytes that Valgrind fails to handle?
Lastly, have you built your own copy of libxcb.so.1? If so, did you
use any GCC options like -march? There are a few amd64 CPU features
that like AVX512 that Valgrind does not support.
Regards
Paul
Hi Paul.
Are the op-code bytes in the information below?
I have not built my own copy of libxcb.so.1
On Leap 16.0 I get the following, the application fails to load.
valgrind installed is 3.25.1-160000.1.1. Same for X11 and Wayland
steve@linux-qw83:~> valgrind quasar
==18853== Memcheck, a memory error detector
==18853== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al.
==18853== Using Valgrind-3.25.1 and LibVEX; rerun with -h for copyright info
==18853== Command: quasar
==18853==
vex x86->IR: unhandled instruction bytes: 0x66 0xF 0x38 0x39
==18853== valgrind: Unrecognised instruction at address 0x453bc82.
==18853== at 0x453BC82: UnknownInlinedFun (xcb_conn.c:262)
==18853== by 0x453BC82: _xcb_conn_wait.part.0 (xcb_conn.c:553)
==18853== by 0x453BF4C: UnknownInlinedFun (xcb_out.c:469)
==18853== by 0x453BF4C: _xcb_out_send (xcb_out.c:470)
==18853== by 0x453EE4A: UnknownInlinedFun (xcb_conn.c:166)
==18853== by 0x453EE4A: xcb_connect_to_fd (xcb_conn.c:385)
==18853== by 0x453F909: xcb_connect_to_display_with_auth_info
(xcb_util.c:565)
==18853== by 0x453FA3D: xcb_connect (xcb_util.c:522)
==18853== by 0x40DADAA: _XConnectXCB (xcb_disp.c:78)
==18853== by 0x40CC3FA: XOpenDisplay (OpenDis.c:129)
==18853== by 0x86EEFE2: qt_init_internal__FPiPPcP9_XDisplayUlUl (in
/opt/quasar/bin/quasar)
==18853== by 0x86EFF83: qt_init__FPiPPcQ212QApplication4Type (in
/opt/quasar/bin/quasar)
==18853== by 0x873145B:
construct__12QApplicationRiPPcQ212QApplication4Type (in
/opt/quasar/bin/quasar)
==18853== by 0x87312F7: __12QApplicationRiPPc (in /opt/quasar/bin/quasar)
==18853== by 0x818B585: main (in /opt/quasar/bin/quasar)
On Leap 15.0 running in a VM.
I get the following where the application runs ok.
steve@linux-b1cb:~> valgrind quasar
==9455== Memcheck, a memory error detector
==9455== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==9455== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==9455== Command: quasar
==9455==
On Leap 15.6 the application loads, the installed valgrind is
3.25.1-350.d_t.1
steve@rnd2:~> valgrind quasar
==6438== Memcheck, a memory error detector
==6438== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al.
==6438== Using Valgrind-3.25.1 and LibVEX; rerun with -h for copyright info
==6438== Command: quasar
I am not sure where to start to debug this.
This application has worked on and off with valgrind from before Leap
42.3. Some times it wouldn't work, then there would be an update to
valgrind and it would work so I would stick with that version until
until a distribution update and go through it all again.
Cheers,
Steve
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