From: Dmitry Vyukov <dvyukov@google.com>
To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, x86@kernel.org, arnd@arndb.de,
linux-arch@vger.kernel.org, ryabinin.a.a@gmail.com
Cc: kasan-dev@googlegroups.com, glider@google.com,
Dmitry Vyukov <dvyukov@google.com>
Subject: [PATCH v4] vmlinux.lds: account for destructor sections
Date: Fri, 1 Jul 2016 17:19:23 +0200 [thread overview]
Message-ID: <1467386363-120030-1-git-send-email-dvyukov@google.com> (raw)
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. 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
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.
Cc: <stable@vger.kernel.org> # v4.0+
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
---
Changes since v1:
- discard .dtors
- don't define .mem sections
Changes since v2:
- use 'vmlinux.lds' subsystem prefix instead of 'kasan'
Changes since v3:
- add 'Cc: <stable@vger.kernel.org> # v4.0+' tag
- CC linux-kernel@vger.kernel.org,akpm@linux-foundation.org
---
include/asm-generic/vmlinux.lds.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 6a67ab9..081d0f2 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -542,15 +542,19 @@
#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 \
--
2.8.0.rc3.226.g39d4020
next reply other threads:[~2016-07-01 15:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-01 15:19 Dmitry Vyukov [this message]
2016-07-01 15:20 ` [PATCH v4] vmlinux.lds: account for destructor sections Dmitry Vyukov
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