objtool: Fix off-by-one in symbol_by_offset()

Sometimes, WARN_FUNC() and other users of symbol_by_offset() will
associate the first instruction of a symbol with the symbol preceding
it.  This is because symbol->offset + symbol->len is already outside of
the symbol's range.

Fixes: 2a362ec ("objtool: Optimize find_symbol_*() and read_symbols()")
Signed-off-by: Julien Thierry <[email protected]>
Reviewed-by: Miroslav Benes <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>

Author: Julien Thierry

tools/objtool/elf.c

@@ -105,7 +105,7 @@ static int symbol_by_offset(const void *key, const struct rb_node *node)
 
 	if (*o < s->offset)
 		return -1;
-	if (*o > s->offset + s->len)
+	if (*o >= s->offset + s->len)
 		return 1;
 
 	return 0;