On samus board, build an image with glibc 2.27.
mosys crashed with SIGSYS


backstrace looks like


__libc_open64 
file_lock_open_or_create()
mosys::main()

The source code of __libc_open64 looks like
int
__libc_open64 (const char *file, int oflag, ...)
{
  int mode = 0;

  if (__OPEN_NEEDS_MODE (oflag))
    {
      va_list arg;
      va_start (arg, oflag);
      mode = va_arg (arg, int);
      va_end (arg);
    }

  return SYSCALL_CANCEL (openat, AT_FDCWD, file, oflag | EXTRA_OPEN_FLAGS,
                         mode);
}

It failed on SYSCALL_CANCEL().

In glibc, this commit

Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Fri Nov 11 15:00:03 2016 -0200

    Consolidate Linux open implementation
    
    This patch consolidates the open Linux syscall implementation on
    sysdeps/unix/sysv/linux/open{64}.c.  The changes are:
    
      1. Remove open{64} from auto-generation syscalls.list.
      2. Add a new open{64}.c implementation.  For architectures that
         define __OFF_T_MATCHES_OFF64_T the default open64 will create
         alias to required open symbols.
      3. Use __NR_openat as default syscall for open{64}.

changes the __libc_open64 to call
return SYSCALL_CANCEL (openat, AT_FDCWD, file, oflag | EXTRA_OPEN_FLAGS,   mode)
instead of 
return SYSCALL_CANCEL (open, file, oflag | O_LARGEFILE, mode)

Maybe this is caused by this change on glibc?