5:49 p.m.
Notification time stamped 2023-03-31 22:49:32 UTC
From 9b284f749c9ddfdc6f59a440e1d842acd66f16d7 Mon Sep 17 00:00:00 2001
From: Keith Seitz <keiths(a)redhat.com>
Date: Mar 31 2023 21:09:01 +0000
Subject: Backport "Fix crash in inside_main_func"
Resolves: rhbz#2183595
---
diff --git a/_gdb.spec.Patch.include b/_gdb.spec.Patch.include
index 259715b..fa4a22c 100644
--- a/_gdb.spec.Patch.include
+++ b/_gdb.spec.Patch.include
@@ -253,3 +253,7 @@ Patch059: gdb-rhbz1553104-s390x-arch12-test.patch
# [aarch64] Backport fix from Luis Machado for RH BZ 2177655.
Patch060: gdb-rhbz2177655-aarch64-pauth-valid-regcache.patch
+# Backport "Fix crash in inside_main_func"
+# (Tom Tromey, RHBZ 2183595)
+Patch061: gdb-rhbz2183595-rustc-inside_main.patch
+
diff --git a/_gdb.spec.patch.include b/_gdb.spec.patch.include
index 3a533c1..12bf93a 100644
--- a/_gdb.spec.patch.include
+++ b/_gdb.spec.patch.include
@@ -58,3 +58,4 @@
%patch058 -p1
%patch059 -p1
%patch060 -p1
+%patch061 -p1
diff --git a/_patch_order b/_patch_order
index c7e631a..d28e8f9 100644
--- a/_patch_order
+++ b/_patch_order
@@ -58,3 +58,4 @@ gdb-linux_perf-bundle.patch
gdb-libexec-add-index.patch
gdb-rhbz1553104-s390x-arch12-test.patch
gdb-rhbz2177655-aarch64-pauth-valid-regcache.patch
+gdb-rhbz2183595-rustc-inside_main.patch
diff --git a/gdb-rhbz2183595-rustc-inside_main.patch
b/gdb-rhbz2183595-rustc-inside_main.patch
new file mode 100644
index 0000000..16a77b6
--- /dev/null
+++ b/gdb-rhbz2183595-rustc-inside_main.patch
@@ -0,0 +1,136 @@
+From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
+From: Tom Tromey <tromey(a)adacore.com>
+Date: Fri, 24 Feb 2023 10:40:16 -0700
+Subject: gdb-rhbz2183595-rustc-inside_main.patch
+
+;; Backport "Fix crash in inside_main_func"
+;; (Tom Tromey, RHBZ 2183595)
+
+gdb 13.1 crashes while running the rust compiler's debugger tests.
+The crash has a number of causes.
+
+First, the rust compiler still uses the C++-like _Z mangling, but with
+its own twist -- some hex digits added to the end of a symbol. So,
+while gdb finds the correct name of "main":
+
+(top-gdb) p name
+$13 = 0x292e0c0 "rustc_gdb_1031745::main"
+
+It isn't found in the minsyms, because C++ demangling yields:
+
+[99] t 0x90c0 _ZN17rustc_gdb_10317454main17h5b5be7fe16a97225E section .text
rustc_gdb_1031745::main::h5b5be7fe16a97225 zko06yobckx336v
+
+This could perhaps be fixed. I also filed a new PR to suggest
+preferring the linkage name of the main program.
+
+Next, the rust compiler emits both a DW_TAG_subprogram and a
+DW_TAG_namespace for "main". This happens because the file is named
+"main.rs" -- i.e., the bug is specific to the source file name. The
+crash also seems to require the nested function inside of 'main', at
+least for me. The namespace always is generated, but perhaps this
+changes the ordering in the DWARF.
+
+When inside_main_func looks up the main symbol, it finds the namespace
+symbol rather than the function. (I filed a bug about fixing gdb's
+symbol tables -- long overdue.)
+
+Meanwhile, as I think it's important to fix this crash sooner rather
+than later, this patch changes inside_main_func to check that the
+symbol that is found is LOC_BLOCK. This perhaps should have been done
+in the first place, anyway.
+
+Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30158
+
+diff --git a/gdb/frame.c b/gdb/frame.c
+--- a/gdb/frame.c
++++ b/gdb/frame.c
+@@ -2453,6 +2453,14 @@ inside_main_func (frame_info_ptr this_frame)
+ if (bs.symbol == nullptr)
+ return false;
+
++ /* We might have found some unrelated symbol. For example, the
++ Rust compiler can emit both a subprogram and a namespace with
++ the same name in the same scope; and due to how gdb's symbol
++ tables currently work, we can't request the one we'd
++ prefer. */
++ if (bs.symbol->aclass () != LOC_BLOCK)
++ return false;
++
+ const struct block *block = bs.symbol->value_block ();
+ gdb_assert (block != nullptr);
+ sym_addr = block->start ();
+diff --git a/gdb/testsuite/gdb.rust/main-crash.exp
b/gdb/testsuite/gdb.rust/main-crash.exp
+new file mode 100644
+--- /dev/null
++++ b/gdb/testsuite/gdb.rust/main-crash.exp
+@@ -0,0 +1,35 @@
++# Copyright (C) 2023 Free Software Foundation, Inc.
++
++# This program is free software; you can redistribute it and/or modify
++# it under the terms of the GNU General Public License as published by
++# the Free Software Foundation; either version 3 of the License, or
++# (at your option) any later version.
++#
++# This program is distributed in the hope that it will be useful,
++# but WITHOUT ANY WARRANTY; without even the implied warranty of
++# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
++# GNU General Public License for more details.
++#
++# You should have received a copy of the GNU General Public License
++# along with this program. If not, see <http://www.gnu.org/licenses/>;.
++
++# Regression test for a crash in inside_main_func.
++
++load_lib rust-support.exp
++require allow_rust_tests
++
++standard_testfile main.rs
++if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
++ {debug rust}]} {
++ return -1
++}
++
++set line [gdb_get_line_number "BREAK"]
++# The bug was that this would crash.
++if {![runto ${srcfile}:$line]} {
++ untested "could not run to breakpoint"
++ return -1
++}
++
++# Test that gdb is alive.
++gdb_test "print 23" " = 23"
+diff --git a/gdb/testsuite/gdb.rust/main.rs b/gdb/testsuite/gdb.rust/main.rs
+new file mode 100644
+--- /dev/null
++++ b/gdb/testsuite/gdb.rust/main.rs
+@@ -0,0 +1,30 @@
++// Copyright (C) 2016-2023 Free Software Foundation, Inc.
++
++// This program is free software; you can redistribute it and/or modify
++// it under the terms of the GNU General Public License as published by
++// the Free Software Foundation; either version 3 of the License, or
++// (at your option) any later version.
++//
++// This program is distributed in the hope that it will be useful,
++// but WITHOUT ANY WARRANTY; without even the implied warranty of
++// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
++// GNU General Public License for more details.
++//
++// You should have received a copy of the GNU General Public License
++// along with this program. If not, see <http://www.gnu.org/licenses/>;.
++
++#![allow(dead_code)]
++#![allow(unused_variables)]
++#![allow(unused_assignments)]
++
++fn global_fn(x: u8) {
++ // BREAK
++}
++
++fn main() {
++ fn nested(y: u8) {
++ global_fn(y)
++ }
++
++ nested(23);
++}
diff --git a/gdb.spec b/gdb.spec
index 259d8e6..7f2db45 100644
--- a/gdb.spec
+++ b/gdb.spec
@@ -57,7 +57,7 @@ Version: 13.1
# The release always contains a leading reserved number, start it at 1.
# `upstream' is not a part of `name' to stay fully rpm dependencies compatible
for the testing.
-Release: 2%{?dist}
+Release: 3%{?dist}
License: GPLv3+ and GPLv3+ with exceptions and GPLv2+ and GPLv2+ with exceptions and GPL+
and LGPLv2+ and LGPLv3+ and BSD and Public Domain and GFDL
# Do not provide URL for snapshots as the file lasts there only for 2 days.
@@ -1192,6 +1192,10 @@ fi
%endif
%changelog
+* Fri Mar 31 2023 Keith Seitz <keiths(a)redhat.com> - 13.1-3
+- Backport "Fix crash in inside_main_func".
+ (Tom Tromey, RHBZ 2183595)
+
* Fri Mar 24 2023 Kevin Buettner <kevinb(a)redhat.com> - 13.1-2
- Backport fix for RHBZ 2177655. (Luis Machado)
https://src.fedoraproject.org/rpms/gdb/c/9b284f749c9ddfdc6f59a440e1d842ac...