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    SubjectRe: [PATCH 4/7] x86/entry: Increase entry_stack size to a full page
    On Thu, 18 Jun 2020 at 16:50, Peter Zijlstra <peterz@infradead.org> wrote:
    >
    > Marco crashed in bad_iret with a Clang11/KCSAN build due to
    > overflowing the stack. Now that we run C code on it, expand it to a
    > full page.
    >
    > Suggested-by: Andy Lutomirski <luto@amacapital.net>
    > Reported-by: Marco Elver <elver@google.com>
    > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

    This fixes the unpredictable crashes.

    Tested-by: Marco Elver <elver@google.com>

    Thanks!


    > ---
    > arch/x86/include/asm/processor.h | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > --- a/arch/x86/include/asm/processor.h
    > +++ b/arch/x86/include/asm/processor.h
    > @@ -370,7 +370,7 @@ struct x86_hw_tss {
    > #define IO_BITMAP_OFFSET_INVALID (__KERNEL_TSS_LIMIT + 1)
    >
    > struct entry_stack {
    > - unsigned long words[64];
    > + char stack[PAGE_SIZE];
    > };
    >
    > struct entry_stack_page {
    >
    >

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