Reduce false positives of module_has_debuginfo()

The module_has_debuginfo() function is heuristic and only checks the
first symbol to see whether drgn knows of it. Let's increase this to the
first 5 symbols (truly, just a magic number) which eliminates some
observed false positives in the wild.

I'm willing to do this somewhat scattershot approach beacuse we're not
far from switching to drgn's new Module API. This will allow us to drop
this heuristic function and just query the Module API for the status of
the debuginfo file.

Orabug: 37894875

Signed-off-by: Stephen Brennan <[email protected]>

Author: brenns10

drgn_tools/module.py

@@ -450,14 +450,13 @@ def module_symbols(module: Object) -> List[Tuple[str, Object]]:
     return syms
 
 
-def _first_kallsyms_symbol(module: Object) -> Optional[int]:
+def _first_kallsyms_symbols(module: Object, count: int) -> List[int]:
     try:
         ks = module.kallsyms
     except AttributeError:
         ks = module
-    if ks.num_symtab >= 2:
-        return int(ks.symtab[1].st_value)
-    return None
+    end = min(count + 1, ks.num_symtab)
+    return [int(ks.symtab[i].st_value) for i in range(1, end)]
 
 
 def module_has_debuginfo(module: Object) -> bool:
@@ -471,14 +470,14 @@ def module_has_debuginfo(module: Object) -> bool:
     """
     if module.prog_.cache.get("using_ctf"):
         return True
-    fst = _first_kallsyms_symbol(module)
-    if not fst:
-        return False
-    try:
-        module.prog_.symbol(fst)
-        return True
-    except LookupError:
-        return False
+    addrs = _first_kallsyms_symbols(module, 5)
+    for addr in addrs:
+        try:
+            module.prog_.symbol(addr)
+            return True
+        except LookupError:
+            pass
+    return False
 
 
 def _elf_sym_to_symbol(name: str, obj: Object) -> Symbol: