--- wikisrc/users/leot/aarch64_problems.mdwn	2018/07/24 00:09:53	1.8
+++ wikisrc/users/leot/aarch64_problems.mdwn	2019/01/04 22:26:31	1.12
@@ -4,18 +4,123 @@ Here a list of possible problems of NetB
 investigation in order to write proper PR or better yet to fix them!
 
 
-## `mpv` and NetBSD crashes
+## `mpv` SIGSEGVs (strnlen(s, (size_t)-1) always returns -1)
+
+**UPDATE**: This was fixed by `<ryo>`, thanks!
+
 Just by invoking `mpv` via:
 
-    $ mpv
+    % mpv
+
+It SEGV as follows:
 
-It is possible to completely crash NetBSD on aarch64. Investigate why and if
-possible get a complete backtrace.
+    % mpv
+    /usr/pkg/lib/ffmpeg4/libavcodec.so.58: text relocations
+    mpv 0.29.0 Copyright © 2000-2018 mpv/MPlayer/mplayer2 projects
+     built on Sat Jul 28 21:02:57 CEST 2018
+    ffmpeg library versions:
+       libavutil       56.14.100
+       libavcodec      58.18.100
+       libavformat     58.12.100
+       libswscale      5.1.100
+       libavfilter     7.16.100
+       libswresample   3.1.100
+    ffmpeg version: 4.0.2
+    
+    Usage:   mpv [options] [url|path/]filename
+    
+    Basic options:
+     --start=<time>    seek to given (percent, seconds, or hh:mm:ss) position
+     --no-audio        do not play sound
+     --no-video        do not play video
+     --fs              fullscreen playback
+     --sub-file=<file> specify subtitle file to use
+     --playlist=<file> specify playlist file
+    
+     --list-options    list all mpv options
+     --h=<string>      print options which contain the given string in their name
+    
+    [1]   Segmentation fault (core dumped) /usr/pkg/bin/mpv...
+    % gdb -core mpv.core /usr/pkg/bin/mpv
+    Reading symbols from /usr/pkg/bin/mpv...done.
+    [New process 5]
+    [New process 6]
+    [New process 4]
+    [New process 3]
+    [New process 2]
+    [New process 1]
+    Core was generated by `mpv'.
+    Program terminated with signal SIGSEGV, Segmentation fault.
+    #0  0x0000f96f727f40b0 in memcpy () from /usr/lib/libc.so.12
+    [Current thread is 1 (process 5)]
+    (gdb) bt
+    #0  0x0000f96f727f40b0 in memcpy () from /usr/lib/libc.so.12
+    #1  0x00000002001cba34 in __memcpy_ichk (len=18446744073709551615, src=0xf96f6e10fec0, dst=<optimized out>)
+        at /usr/include/ssp/string.h:82
+    #2  strndup_append_at (str=str@entry=0xf96f6f4ff348, at=0, append=0xf96f6e10fec0 "speed", append_len=<optimized out>,
+        append_len@entry=18446744073709551615) at ../ta/ta_utils.c:113
+    #3  0x00000002001cbea4 in ta_strdup_append_buffer (str=str@entry=0xf96f6f4ff348, a=<optimized out>) at ../ta/ta_utils.c:165
+    #4  0x00000002001cb7b8 in ta_talloc_strdup_append_buffer (s=<optimized out>, s@entry=0x0, a=<optimized out>) at ../ta/ta_talloc.c:31
+    #5  0x0000000200157eec in print_str_list (opt=<optimized out>, src=<optimized out>) at ../options/m_option.c:1477
+    [...]
+
+This happens because `strnlen(s, (size_t)-1)`, always returns -1, e.g.:
+
+    % cat strnlen_size_max.c
+    #include <stdio.h>
+    #include <string.h>
+    
+    
+    int
+    main(int argc, char *argv[])
+    {
+    	int i;
+    	for (i = 1; i < argc; i++) {
+    		printf("strnlen(\"%s\", (size_t)-1) -> %ld\n",
+    		    argv[i], strnlen(argv[i], ~(size_t)0));
+    	}
+    
+    	return 0;
+    }
+    % gcc -Wall strnlen_size_max.c
+    % ./a.out foo
+    strnlen("foo", (size_t)-1) -> -1
 
-(Is it PaX MPROTECT related?)
+(This should returns 3, not -1!)
 
+The following patch workaround the mpv problem by avoiding all
+`strnlen(s, (size_t)-1)` calls (and just using strlen() instead):
+
+    $NetBSD: aarch64_problems.mdwn,v 1.11 2018/07/31 22:22:28 leot Exp $
+    
+    Avoid to directly call:
+    
+     strnlen(s, (size_t)-1)
+    
+    because on aarch64 ATM it (incorrectly) always returns -1 (also
+    when s is a string with less than SIZE_MAX characters).
+    
+    Add a kludge in order to use strlen() in these cases.
+    
+    --- ta/ta_utils.c.orig	2018-07-31 21:45:47.492269366 +0000
+    +++ ta/ta_utils.c
+    @@ -98,7 +98,11 @@ static bool strndup_append_at(char **str
+         if (!*str && !append)
+             return true; // stays NULL, but not an OOM condition
+     
+    -    size_t real_len = append ? strnlen(append, append_len) : 0;
+    +    size_t real_len = append ?
+    +	append_len == (size_t)-1 ?
+    +	   strlen(append) :
+    +	   strnlen(append, append_len) :
+    +	0;
+         if (append_len > real_len)
+             append_len = real_len;
+ 
 
 ## Python `import requests` SIGILLs
+
+**UPDATE**: A kludge was added since py-cffi-1.11.5nb1 to avoid that.
 Doing a (please note that also `python36` is affected):
 
     $ python2.7 -c 'import requests'
@@ -130,23 +235,8 @@ Doing a (please note that also `python36
     #define _cffi_save_errno                                                 \
         ((void(*)(void))_cffi_exports[14])
 
-The following patch workaround the issue:
-
-    $NetBSD: aarch64_problems.mdwn,v 1.7 2018/07/23 22:51:09 leot Exp $
-    
-    Kludge for NetBSD/aarch64 SIGILL.
-    
-    --- setup.py.orig	2018-02-27 18:15:41.000000000 +0000
-    +++ setup.py
-    @@ -70,7 +70,7 @@ def ask_supports_thread():
-         ok = (sys.platform != 'win32' and
-               config.try_compile('__thread int some_threadlocal_variable_42;'))
-         if ok:
-    -        define_macros.append(('USE__THREAD', None))
-    +        pass
-         else:
-             ok1 = config.try_compile('int some_regular_variable_42;')
-             if not ok1:
+Since py-cffi-1.11.5nb1 a kludge to workaround the issue is present (by
+disabling __thread).
 
 
 ## polkitd crashes