(unless of course the caller is expected to)

@@ -56,18 +57,24 @@ dwfl_module_getsrc (Dwfl_Module *mod, Dwarf_Addr addr)
   Dwarf_Addr bias;
   if (INTUSE(dwfl_module_getdwarf) (mod, &bias) == NULL)
     return NULL;
+  fprintf(stderr, "got dwarf 0x%lx\n", addr);
 
   struct dwfl_cu *cu;
   Dwfl_Error error = __libdwfl_addrcu (mod, addr, &cu);
   if (likely (error == DWFL_E_NOERROR))
     error = __libdwfl_cu_getsrclines (cu);
+  fprintf(stderr, "got addrcu\n");
   if (likely (error == DWFL_E_NOERROR))
     {
+      addr = addr - bias;
+      fprintf(stderr, "searching unbiased 0x%lx\n", (long) addr);
       /* The lines are sorted by address, so we can use binary search.  */
       size_t l = 0, u = cu->die.cu->lines->nlines;
       while (l < u)
        {
          size_t idx = (l + u) / 2;
+         fprintf(stderr, "%d 0x%lx\n", (int)idx,
+                 (long) cu->die.cu->lines->info[idx].addr);
          if (addr < cu->die.cu->lines->info[idx].addr)
            u = idx;
          else if (addr > cu->die.cu->lines->info[idx].addr)

which gives the improved effect:

got dwarf 0x2aaab057683c
addrarange 2aaab057683c
naranges 859
adjusted 6e83c by bias 2aaab0508000
found arange at 624
got addrcu
searching unbiased 0x6e83c
73 0x6e950
36 0x57fba
55 0x6e87b
46 0x6e83c