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    Subject[PATCH 4.6 18/96] vmlinux.lds: account for destructor sections
    Date
    4.6-stable review patch.  If anyone has any objections, please let me know.

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

    From: Dmitry Vyukov <dvyukov@google.com>

    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@google.com
    Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
    Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    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
    @@ -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 \

    \
     
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