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    Subject[PATCH] x86/traps: print faulty addresses on stack overflow
    Date
    Since commit ad67b74d2469d9b8 ("printk: hash addresses printed with %p"),
    when a stack overflow happens "____ptrval____" is printed instead of the
    real addresses:

    BUG: stack guard page was hit at (____ptrval____) (stack is (____ptrval____)..(____ptrval____))

    Even if leaking kernel layout information is usually a bad thing, probably
    the system needs to be rebooted anyway past this point, so force the
    address print as the obfuscation makes the error message useless.

    Signed-off-by: Matteo Croce <mcroce@redhat.com>
    ---
    arch/x86/kernel/traps.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
    index d26f9e9c3d83..0d3695334dfd 100644
    --- a/arch/x86/kernel/traps.c
    +++ b/arch/x86/kernel/traps.c
    @@ -301,7 +301,7 @@ __visible void __noreturn handle_stack_overflow(const char *message,
    struct pt_regs *regs,
    unsigned long fault_address)
    {
    - printk(KERN_EMERG "BUG: stack guard page was hit at %p (stack is %p..%p)\n",
    + printk(KERN_EMERG "BUG: stack guard page was hit at %px (stack is %px..%px)\n",
    (void *)fault_address, current->stack,
    (char *)current->stack + THREAD_SIZE - 1);
    die(message, regs, 0);
    --
    2.20.1
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