[PATCH 4.4 14/68] vmlinux.lds: account for destructor sections

From: Greg Kroah-Hartman
Date: Mon Aug 08 2016 - 15:47:42 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>

commit e41f501d391265ff568f3e49d6128cc30856a36f upstream.

If CONFIG_KASAN is enabled and gcc is configured with
--disable-initfini-array and/or gold linker is used, gcc emits
.ctors/.dtors and .text.startup/.text.exit sections instead of
.init_array/.fini_array. .dtors section is not explicitly accounted in
the linker script and messes vvar/percpu layout.

We want:
ffffffff822bfd80 D _edata
ffffffff822c0000 D __vvar_beginning_hack
ffffffff822c0000 A __vvar_page
ffffffff822c0080 0000000000000098 D vsyscall_gtod_data
ffffffff822c1000 A __init_begin
ffffffff822c1000 D init_per_cpu__irq_stack_union
ffffffff822c1000 A __per_cpu_load
ffffffff822d3000 D init_per_cpu__gdt_page

We got:
ffffffff8279a600 D _edata
ffffffff8279b000 A __vvar_page
ffffffff8279c000 A __init_begin
ffffffff8279c000 D init_per_cpu__irq_stack_union
ffffffff8279c000 A __per_cpu_load
ffffffff8279e000 D __vvar_beginning_hack
ffffffff8279e080 0000000000000098 D vsyscall_gtod_data
ffffffff827ae000 D init_per_cpu__gdt_page

This happens because __vvar_page and .vvar get different addresses in
arch/x86/kernel/vmlinux.lds.S:

. = ALIGN(PAGE_SIZE);
__vvar_page = .;

.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
/* work around gold bug 13023 */
__vvar_beginning_hack = .;

Discard .dtors/.fini_array/.text.exit, since we don't call dtors.
Merge .text.startup into init text.

Link: http://lkml.kernel.org/r/1467386363-120030-1-git-send-email-dvyukov@xxxxxxxxxx
Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
include/asm-generic/vmlinux.lds.h | 4 ++++
1 file changed, 4 insertions(+)

--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -531,15 +531,19 @@

#define INIT_TEXT \
*(.init.text) \
+ *(.text.startup) \
MEM_DISCARD(init.text)

#define EXIT_DATA \
*(.exit.data) \
+ *(.fini_array) \
+ *(.dtors) \
MEM_DISCARD(exit.data) \
MEM_DISCARD(exit.rodata)

#define EXIT_TEXT \
*(.exit.text) \
+ *(.text.exit) \
MEM_DISCARD(exit.text)

#define EXIT_CALL \