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Re: [patch+8.1] Fix -D_GLIBCXX_DEBUG gdb-add-index regression
- From: Simon Marchi <simon dot marchi at ericsson dot com>
- To: Jan Kratochvil <jan dot kratochvil at redhat dot com>, <gdb-patches at sourceware dot org>
- Cc: Sergio Durigan Junior <sergiodj at redhat dot com>
- Date: Thu, 12 Apr 2018 15:21:28 -0400
- Subject: Re: [patch+8.1] Fix -D_GLIBCXX_DEBUG gdb-add-index regression
- References: <20180204193754.GA29011@host1.jankratochvil.net>
- Spamdiagnosticmetadata: NSPM
- Spamdiagnosticoutput: 1:99
Hi Jan,
Sorry I missed this patch, but found out about it from your bug report.
On 2018-02-04 02:37 PM, Jan Kratochvil wrote:
> Hi,
>
> gdb: Out-of-bounds vector access while running gdb-add-index
> https://bugzilla.redhat.com/show_bug.cgi?id=1540559
>
> Fedora Rawhide started to use -D_GLIBCXX_DEBUG which made gdb-add-index
> failing.
>
> /usr/include/c++/7/debug/safe_iterator.h:270:
> Error: attempt to dereference a past-the-end iterator.
> Objects involved in the operation:
> iterator "this" @ 0x0x7fffffffcb90 {
> type = __gnu_debug::_Safe_iterator<__gnu_cxx::__normal_iterator<unsigned char*, std::__cxx1998::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > >, std::__debug::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > > (mutable iterator);
> state = past-the-end;
> references sequence with type 'std::__debug::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > >' @ 0x0x7fffffffcc50
> }
>
> /usr/include/c++/7/debug/vector:417:
> Error: attempt to subscript container with out-of-bounds index 556, but
> container only holds 556 elements.
> Objects involved in the operation:
> sequence "this" @ 0x0x2e87af8 {
> type = std::__debug::vector<partial_symbol*, std::allocator<partial_symbol*> >;
> }
>
> I do not know if anyone regression-tests GDB with -D_GLIBCXX_DEBUG,
> I have just checked -D_GLIBCXX_DEBUG run against gdb-add-index.
I didn't know about this before you reported those bugs. I've added it to my
build, and suggested to Sergio that we add it to the buildbot.
> The two -D_GLIBCXX_DEBUG regressions were made by:
>
> commit bc8f2430e08cc2a520db49a42686e0529be4a3bc
> Author: Jan Kratochvil <jan.kratochvil@redhat.com>
> Date: Mon Jun 12 16:29:53 2017 +0100
> Code cleanup: C++ify .gdb_index producer
>
> commit af5bf4ada48ff65b6658be1fab8f9c8f8ab5f319
> Author: Simon Marchi <simon.marchi@ericsson.com>
> Date: Sat Oct 14 08:06:29 2017 -0400
> Replace psymbol_allocation_list with std::vector
>
> No regressions on {x86_64,x86_64-m32,i686}-fedorarawhide-linux-gnu.
>
> OK for check-in?
LGTM. But that code has moved to dwarf-index-write.c, and I feel bad
because your patch was posted way before the move. So I adjusted it
to save you a bit of time (please make sure I didn't mess up anything).
>From 0f437317476d4eacf220c03f58baaf595a5c0cee Mon Sep 17 00:00:00 2001
From: Jan Kratochvil <jan.kratochvil@redhat.com>
Date: Sun, 4 Feb 2018 20:37:54 +0100
Subject: [PATCH] Fix -D_GLIBCXX_DEBUG gdb-add-index regression
Hi,
gdb: Out-of-bounds vector access while running gdb-add-index
https://bugzilla.redhat.com/show_bug.cgi?id=1540559
Fedora Rawhide started to use -D_GLIBCXX_DEBUG which made gdb-add-index
failing.
/usr/include/c++/7/debug/safe_iterator.h:270:
Error: attempt to dereference a past-the-end iterator.
Objects involved in the operation:
iterator "this" @ 0x0x7fffffffcb90 {
type = __gnu_debug::_Safe_iterator<__gnu_cxx::__normal_iterator<unsigned char*, std::__cxx1998::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > >, std::__debug::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > > > (mutable iterator);
state = past-the-end;
references sequence with type 'std::__debug::vector<unsigned char, gdb::default_init_allocator<unsigned char, std::allocator<unsigned char> > >' @ 0x0x7fffffffcc50
}
/usr/include/c++/7/debug/vector:417:
Error: attempt to subscript container with out-of-bounds index 556, but
container only holds 556 elements.
Objects involved in the operation:
sequence "this" @ 0x0x2e87af8 {
type = std::__debug::vector<partial_symbol*, std::allocator<partial_symbol*> >;
}
I do not know if anyone regression-tests GDB with -D_GLIBCXX_DEBUG,
I have just checked -D_GLIBCXX_DEBUG run against gdb-add-index.
The two -D_GLIBCXX_DEBUG regressions were made by:
commit bc8f2430e08cc2a520db49a42686e0529be4a3bc
Author: Jan Kratochvil <jan.kratochvil@redhat.com>
Date: Mon Jun 12 16:29:53 2017 +0100
Code cleanup: C++ify .gdb_index producer
commit af5bf4ada48ff65b6658be1fab8f9c8f8ab5f319
Author: Simon Marchi <simon.marchi@ericsson.com>
Date: Sat Oct 14 08:06:29 2017 -0400
Replace psymbol_allocation_list with std::vector
No regressions on {x86_64,x86_64-m32,i686}-fedorarawhide-linux-gnu.
OK for check-in?
Jan
gdb/ChangeLog
2018-02-04 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (data_buf::grow) (write_one_signatured_type)
(recursively_write_psymbols) (debug_names::recursively_write_psymbols)
(debug_names::write_one_signatured_type): Fix -D_GLIBCXX_DEBUG
regression.
---
gdb/dwarf-index-write.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/gdb/dwarf-index-write.c b/gdb/dwarf-index-write.c
index 4c596c2..a5e196d 100644
--- a/gdb/dwarf-index-write.c
+++ b/gdb/dwarf-index-write.c
@@ -154,7 +154,7 @@ private:
gdb_byte *grow (size_t size)
{
m_vec.resize (m_vec.size () + size);
- return &*m_vec.end () - size;
+ return &*(m_vec.end () - size);
}
gdb::byte_vector m_vec;
@@ -588,12 +588,14 @@ write_one_signatured_type (void **slot, void *d)
write_psymbols (info->symtab,
info->psyms_seen,
- &info->objfile->global_psymbols[psymtab->globals_offset],
+ (info->objfile->global_psymbols.data ()
+ + psymtab->globals_offset),
psymtab->n_global_syms, info->cu_index,
0);
write_psymbols (info->symtab,
info->psyms_seen,
- &info->objfile->static_psymbols[psymtab->statics_offset],
+ (info->objfile->static_psymbols.data ()
+ + psymtab->statics_offset),
psymtab->n_static_syms, info->cu_index,
1);
@@ -643,12 +645,12 @@ recursively_write_psymbols (struct objfile *objfile,
write_psymbols (symtab,
psyms_seen,
- &objfile->global_psymbols[psymtab->globals_offset],
+ objfile->global_psymbols.data () + psymtab->globals_offset,
psymtab->n_global_syms, cu_index,
0);
write_psymbols (symtab,
psyms_seen,
- &objfile->static_psymbols[psymtab->statics_offset],
+ objfile->static_psymbols.data () + psymtab->statics_offset,
psymtab->n_static_syms, cu_index,
1);
}
@@ -839,10 +841,10 @@ public:
psyms_seen, cu_index);
write_psymbols (psyms_seen,
- &objfile->global_psymbols[psymtab->globals_offset],
+ objfile->global_psymbols.data () + psymtab->globals_offset,
psymtab->n_global_syms, cu_index, false, unit_kind::cu);
write_psymbols (psyms_seen,
- &objfile->static_psymbols[psymtab->statics_offset],
+ objfile->static_psymbols.data () + psymtab->statics_offset,
psymtab->n_static_syms, cu_index, true, unit_kind::cu);
}
@@ -1200,11 +1202,13 @@ private:
struct partial_symtab *psymtab = entry->per_cu.v.psymtab;
write_psymbols (info->psyms_seen,
- &info->objfile->global_psymbols[psymtab->globals_offset],
+ (info->objfile->global_psymbols.data ()
+ + psymtab->globals_offset),
psymtab->n_global_syms, info->cu_index, false,
unit_kind::tu);
write_psymbols (info->psyms_seen,
- &info->objfile->static_psymbols[psymtab->statics_offset],
+ (info->objfile->static_psymbols.data ()
+ + psymtab->statics_offset),
psymtab->n_static_syms, info->cu_index, true,
unit_kind::tu);
--
2.7.4