Re: why does bsearch segfault on custom strcmp when qsort works fine?

I have a program (complete source at the end) which correctly outputs this:
 ["charlie" "foxtrot" "oscar" "echo" "alpha" "golf" "tango" "delta" "bravo"]
["alpha" "bravo" "charlie" "delta" "echo" "foxtrot" "golf" "oscar" "tango"]
check_array OK
check_index_found true OK
check_index_found false OK
 However, if you uncomment the "//#define BUG" line, the output (in gdb) is this:
 (gdb) run
Starting program: /home/mark/tmp/mycmpstr/mycmpstr
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
["charlie" "foxtrot" "oscar" "echo" "alpha" "golf" "tango" "delta" "bravo"]
["alpha" "bravo" "charlie" "delta" "echo" "foxtrot" "golf" "oscar" "tango"]
check_array OK
 Program received signal SIGSEGV, Segmentation fault.
__strcmp_avx2 () at ../sysdeps/x86_64/multiarch/strcmp-avx2.S:283
283 ../sysdeps/x86_64/multiarch/strcmp-avx2.S: No such file or directory.
(gdb) bt
#0  __strcmp_avx2 () at ../sysdeps/x86_64/multiarch/strcmp-avx2.S:283
#1  0x00005555555553e0 in mystrcmp (s=0x555555556030, t=0x7fffffffde10) at mycmpstr.c:50
#2  0x00007ffff7e0a53c in __GI_bsearch (__key=0x555555556030, __base=0x7fffffffddf0,
     __nmemb=<optimized out>, __size=8, __compar=0x5555555553b7 <mystrcmp>)
     at ../bits/stdlib-bsearch.h:33
#3  0x0000555555555317 in main () at mycmpstr.c:30
 The difference is that without BUG defined I use my own binary search,
but with BUG defined I use bsearch.
 [...]
 int mystrcmp(const void* s, const void* t) {
     return strcmp(*(const char**)s, *(const char**)t);

}