When running valgrind on a simple program opening an OpenCV namedWindow (https://docs.opencv.org/3.3.0/d7/dfc/group__highgui.html#ga5afdf8410934fd099df85c75b2e0888b), it reports:

UNKNOWN workq_ops option 128
==88358== valgrind: Unrecognised instruction at address 0x10219bb50.
==88358==    at 0x10219BB50: _dispatch_kq_init (in /usr/lib/system/libdispatch.dylib)

(Full report and example code below)

It is not impossible that this is a bug on OpenCV's site.



Versions etc:

OS:
macOS Sierra 10.12.6 (MB Pro, 15inch, Mid 2015 / 2.8 GHz Intel Core i7)
Installed most things straight with brew package manager.

valgrind --version:
valgrind-3.14.0.SVN
(brew HEAD-16470)

clang --version:
Apple LLVM version 9.0.0 (clang-900.0.37)
Target: x86_64-apple-darwin16.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

pkg-config --modversion opencv:
3.3.0

ls /usr/lib/libstdc++.*:
/usr/lib/libstdc++.6.0.9.dylib
/usr/lib/libstdc++.6.dylib
/usr/lib/libstdc++.dylib



Example code: test.cpp:
```
#include "opencv2/highgui.hpp"

int main(const int argc, const char** const argv) {
  cv::namedWindow("NamedWindow");
  // while (true) if (cv::waitKey(1) != -1) break;
}
```

You might want to add the commented line to see the window in action when running the program normally.



Compile commands:
```
clang -lstdc++ $(pkg-config --cflags --libs opencv) test.cpp -o test
```



Report (simple `valgrind ./test`):
```
==88358== Memcheck, a memory error detector
==88358== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==88358== Using Valgrind-3.14.0.SVN and LibVEX; rerun with -h for copyright info
==88358== Command: ./test
==88358== 
--88358-- run: /usr/bin/dsymutil "./test"
warning: no debug symbols in executable (-arch x86_64)
==88358== Syscall param msg->desc.port.name points to uninitialised byte(s)
==88358==    at 0x1023AF34A: mach_msg_trap (in /usr/lib/system/libsystem_kernel.dylib)
==88358==    by 0x1023AE796: mach_msg (in /usr/lib/system/libsystem_kernel.dylib)
==88358==    by 0x1023A8485: task_set_special_port (in /usr/lib/system/libsystem_kernel.dylib)
==88358==    by 0x10254410E: _os_trace_create_debug_control_port (in /usr/lib/system/libsystem_trace.dylib)
==88358==    by 0x102544458: _libtrace_init (in /usr/lib/system/libsystem_trace.dylib)
==88358==    by 0x1020749DF: libSystem_initializer (in /usr/lib/libSystem.B.dylib)
==88358==    by 0x100018A1A: ImageLoaderMachO::doModInitFunctions(ImageLoader::LinkContext const&) (in /usr/lib/dyld)
==88358==    by 0x100018C1D: ImageLoaderMachO::doInitialization(ImageLoader::LinkContext const&) (in /usr/lib/dyld)
==88358==    by 0x1000144A9: ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&, unsigned int, char const*, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==88358==    by 0x100014440: ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&, unsigned int, char const*, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==88358==    by 0x100013523: ImageLoader::processInitializers(ImageLoader::LinkContext const&, unsigned int, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==88358==    by 0x1000135B8: ImageLoader::runInitializers(ImageLoader::LinkContext const&, ImageLoader::InitializerTimingList&) (in /usr/lib/dyld)
==88358==  Address 0x104889a2c is on thread 1's stack
==88358==  in frame #2, created by task_set_special_port (???:)
==88358== 
--88358-- UNKNOWN mach_msg unhandled MACH_SEND_TRAILER option
--88358-- UNKNOWN mach_msg unhandled MACH_SEND_TRAILER option (repeated 2 times)
--88358-- UNKNOWN mach_msg unhandled MACH_SEND_TRAILER option (repeated 4 times)
UNKNOWN workq_ops option 128
==88358== valgrind: Unrecognised instruction at address 0x10219bb50.
==88358==    at 0x10219BB50: _dispatch_kq_init (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1021998FB: _dispatch_client_callout (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1021998B8: dispatch_once_f (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219BA90: _dispatch_kq_update (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219D0CD: _dispatch_kevent_resume (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219D03D: _dispatch_source_kevent_resume (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219CE85: _dispatch_source_kevent_register (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1021AC651: _dispatch_queue_resume_finalize_activation (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1024EC3C0: _notify_lib_init (in /usr/lib/system/libsystem_notify.dylib)
==88358==    by 0x1024EC9AB: notify_register_dispatch (in /usr/lib/system/libsystem_notify.dylib)
==88358==    by 0x1088BF916: CFUniCharMapTo (in /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation)
==88358==    by 0x1021998FB: _dispatch_client_callout (in /usr/lib/system/libdispatch.dylib)
==88358== Your program just tried to execute an instruction that Valgrind
==88358== did not recognise.  There are two possible reasons for this.
==88358== 1. Your program has a bug and erroneously jumped to a non-code
==88358==    location.  If you are running Memcheck and you just saw a
==88358==    warning about a bad jump, it's probably your program's fault.
==88358== 2. The instruction is legitimate but Valgrind doesn't handle it,
==88358==    i.e. it's Valgrind's fault.  If you think this is the case or
==88358==    you are not sure, please let us know and we'll try to fix it.
==88358== Either way, Valgrind will now raise a SIGILL signal which will
==88358== probably kill your program.
==88358== 
==88358== Process terminating with default action of signal 4 (SIGILL)
==88358==  Illegal opcode at address 0x10219BB50
==88358==    at 0x10219BB50: _dispatch_kq_init (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1021998FB: _dispatch_client_callout (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1021998B8: dispatch_once_f (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219BA90: _dispatch_kq_update (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219D0CD: _dispatch_kevent_resume (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219D03D: _dispatch_source_kevent_resume (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x10219CE85: _dispatch_source_kevent_register (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1021AC651: _dispatch_queue_resume_finalize_activation (in /usr/lib/system/libdispatch.dylib)
==88358==    by 0x1024EC3C0: _notify_lib_init (in /usr/lib/system/libsystem_notify.dylib)
==88358==    by 0x1024EC9AB: notify_register_dispatch (in /usr/lib/system/libsystem_notify.dylib)
==88358==    by 0x1088BF916: CFUniCharMapTo (in /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation)
==88358==    by 0x1021998FB: _dispatch_client_callout (in /usr/lib/system/libdispatch.dylib)
==88358== 
==88358== HEAP SUMMARY:
==88358==     in use at exit: 2,355,679 bytes in 1,302 blocks
==88358==   total heap usage: 5,463 allocs, 4,161 frees, 4,758,949 bytes allocated
==88358== 
==88358== LEAK SUMMARY:
==88358==    definitely lost: 1,264 bytes in 4 blocks
==88358==    indirectly lost: 0 bytes in 0 blocks
==88358==      possibly lost: 9,792 bytes in 226 blocks
==88358==    still reachable: 69,037 bytes in 741 blocks
==88358==         suppressed: 2,275,586 bytes in 331 blocks
==88358== Rerun with --leak-check=full to see details of leaked memory
==88358== 
==88358== For counts of detected and suppressed errors, rerun with: -v
==88358== Use --track-origins=yes to see where uninitialised values come from
==88358== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 23 from 4)
[1]    88358 illegal hardware instruction  valgrind ./test
```