From FEDORA_PATCHES Mon Sep 17 00:00:00 2001

From: Kevin Buettner <kevinb@redhat.com>

Date: Tue, 8 Dec 2020 14:07:45 -0700

Subject: gdb-rhbz1905996-fix-off-by-one-error-in-ada_fold_name.patch

;; Fix off-by-one error in ada_fold_name.patch (RH BZ 1905996)

;; Upstream patch proposal: https://sourceware.org/pipermail/gdb-patches/2020-December/173935.html

;; =fedoratest

Fix off-by-one error in ada_fold_name

I'm seeing a libstdc++ assertion failure when running GDB's "maint selftest"

command when GDB is configured with the following CFLAGS and CXXFLAGS as

part of the configure line:

  CFLAGS='-D_GLIBCXX_DEBUG -g3 -O0' CXXFLAGS='-D_GLIBCXX_DEBUG -g3 -O0'

This is what I see when running the self tests:

(gdb) maint selftest

Running selftest aarch64-analyze-prologue.

Running selftest aarch64-process-record.

Running selftest arm-record.

Running selftest arm_analyze_prologue.

Running selftest array_view.

Running selftest child_path.

Running selftest cli_utils.

Running selftest command_structure_invariants.

Running selftest copy_bitwise.

Running selftest copy_integer_to_size.

Running selftest cp_remove_params.

Running selftest cp_symbol_name_matches.

Running selftest dw2_expand_symtabs_matching.

/usr/include/c++/11/string_view:211: constexpr const value_type& std::basic_string_view<_CharT, _Traits>::operator[](std::basic_string_view<_CharT, _Traits>::size_type) const [with _CharT = char; _Traits = std::char_traits<char>; std::basic_string_view<_CharT, _Traits>::const_reference = const char&; std::basic_string_view<_CharT, _Traits>::size_type = long unsigned int]: Assertion '__pos < this->_M_len' failed.

Aborted (core dumped)

Here's a partial stack trace:

  #0  0x00007ffff6ef6262 in raise () from /lib64/libc.so.6

  #1  0x00007ffff6edf8a4 in abort () from /lib64/libc.so.6

  #2  0x00000000004249bf in std::__replacement_assert (

      __file=0xef7480 "/usr/include/c++/11/string_view", __line=211,

      __function=0xef7328 "constexpr const value_type& std::basic_string_view<_CharT, _Traits>::operator[](std::basic_string_view<_CharT, _Traits>::size_type) const [with _CharT = char; _Traits = std::char_traits<char>; std::ba"...,

      __condition=0xef7311 "__pos < this->_M_len")

      at /usr/include/c++/11/x86_64-redhat-linux/bits/c++config.h:2624

  #3  0x0000000000451737 in std::basic_string_view<char, std::char_traits<char> >::operator[] (this=0x7fffffffc200, __pos=8)

      at /usr/include/c++/11/string_view:211

  #4  0x00000000004329f5 in ada_fold_name (name="function")

      at /ironwood1/sourceware-git/rawhide-master/bld/../../worktree-master/gdb/ada-lang.c:988

And, looking at frame #4...

(top-gdb) up 4

    at /ironwood1/sourceware-git/rawhide-master/bld/../../worktree-master/gdb/ada-lang.c:988

988		fold_buffer[i] = tolower (name[i]);

(top-gdb) p i

$1 = 8

(top-gdb) p name.size()

$2 = 8

My patch adjusts the comparison to only copy name.size() characters

from the string.  I've added a separate statement for NUL character

termination of fold_buffer[].

gdb/ChangeLog:

	* ada-lang.c (ada_fold_name): Fix off-by-one error.

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c

--- a/gdb/ada-lang.c

+++ b/gdb/ada-lang.c

@@ -1006,8 +1006,9 @@ struct type *

     {

       int i;

-      for (i = 0; i <= len; i += 1)

+      for (i = 0; i < len; i += 1)

         fold_buffer[i] = tolower (name[i]);

+      fold_buffer[i] = '\0';

     }

   return fold_buffer;