Patch "vmlinux.lds: account for destructor sections" has been added to the 4.6-stable tree

This is a note to let you know that I've just added the patch titled

vmlinux.lds: account for destructor sections

to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
vmlinux.lds-account-for-destructor-sections.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dmitry Vyukov <[email protected]>
Date: Thu, 14 Jul 2016 12:07:29 -0700
Subject: vmlinux.lds: account for destructor sections

From: Dmitry Vyukov <[email protected]>

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.

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

@@ -540,15 +540,19 @@
 
 #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							\

Patches currently in stable-queue which might be from [email protected] are

queue-4.6/mm-thp-refix-false-positive-bug-in-page_move_anon_rmap.patch queue-4.6/vmlinux.lds-account-for-destructor-sections.patch queue-4.6/radix-tree-fix-radix_tree_iter_retry-for-tagged-iterators.patch