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61 lines
2.5 KiB
61 lines
2.5 KiB
2 years ago
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From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
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From: Keith Seitz <keiths@redhat.com>
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Date: Mon, 27 Jul 2020 16:34:37 -0400
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Subject: gdb-rhbz1842691-corefile-mem-access-1of15.patch
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;; Remove hack for GDB which sets the section size to 0
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;; Kevin Buettner, RH BZ 1842691
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Author: Kevin Buettner <kevinb@redhat.com>
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Remove hack for GDB which sets the section size to 0
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This commit removes a hack for GDB which was introduced in 2007.
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See:
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https://sourceware.org/ml/binutils/2007-08/msg00044.html
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That hack mostly allowed GDB's handling of core files to continue to
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work without any changes to GDB.
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The problem with setting the section size to zero is that GDB won't
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know how big that section is/was. Often, this doesn't matter because
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the data in question are found in the exec file. But it can happen
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that the section describes memory that had been allocated, but never
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written to. In this instance, the contents of that memory region are
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not written to the core file. Also, since the region in question was
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dynamically allocated, it won't appear in the exec file. We don't
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want these regions to appear as inaccessible to GDB (since they *were*
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accessible when the process was live), so it's important that GDB know
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the size of the region.
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I've made changes to GDB which correctly handles this case. When
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attempting to access memory, GDB will first consider core file data
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for which both SEC_ALLOC and SEC_HAS_CONTENTS is set. Next, if that
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fails, GDB will attempt to find the data in the exec file. Finally,
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if that also fails, GDB will attempt to access memory in the sections
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which are flagged as SEC_ALLOC, but not SEC_HAS_CONTENTS.
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bfd/ChangeLog:
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* elf.c (_bfd_elf_make_section_from_phdr): Remove hack for GDB.
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diff --git a/bfd/elf.c b/bfd/elf.c
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--- a/bfd/elf.c
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+++ b/bfd/elf.c
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@@ -2975,14 +2975,6 @@ _bfd_elf_make_section_from_phdr (bfd *abfd,
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newsect->alignment_power = bfd_log2 (align);
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if (hdr->p_type == PT_LOAD)
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{
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- /* Hack for gdb. Segments that have not been modified do
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- not have their contents written to a core file, on the
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- assumption that a debugger can find the contents in the
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- executable. We flag this case by setting the fake
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- section size to zero. Note that "real" bss sections will
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- always have their contents dumped to the core file. */
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- if (bfd_get_format (abfd) == bfd_core)
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- newsect->size = 0;
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newsect->flags |= SEC_ALLOC;
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if (hdr->p_flags & PF_X)
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newsect->flags |= SEC_CODE;
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