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    SubjectRe: s390 && user_enable_single_step() (Was: odd utrace testing results on s390x)
    On 01/07, Martin Schwidefsky wrote:
    >
    > On Wed, 6 Jan 2010 13:08:12 -0800 (PST)
    > Roland McGrath <roland@redhat.com> wrote:
    >
    > > That's what tracehook_signal_handler is for. You're both doing it yourself
    > > in the arch code (by setting TIF_SINGLE_STEP), and then telling the generic
    > > code to do it (by passing stepping=1 to tracehook_signal_handler).
    >
    > Ok, so with the full utrace the semantics of tracehook_signal_handler
    > is more than just causing a SIGTRAP. It is an indication for a signal
    > AND a SIGTRAP if single-stepping is active. To make both cases work we
    > should stop setting TIF_SINGLE_STEP in do_signal and pass
    > current->thread.per_info.single_step to tracehook_signal_handler
    > instead of test_thread_flag(TIF_SINGLE_STEP).

    Can't understand why do we need TIF_SINGLE_STEP at all.

    Just pass current->thread.per_info.single_step to
    tracehook_signal_handler() ?

    Oleg.

    --- a/arch/s390/kernel/signal.c
    +++ b/arch/s390/kernel/signal.c
    @@ -504,14 +504,8 @@ void do_signal(struct pt_regs *regs)
    * for a normal instruction, act like we took
    * one for the handler setup.
    */
    - if (current->thread.per_info.single_step)
    - set_thread_flag(TIF_SINGLE_STEP);
    -
    - /*
    - * Let tracing know that we've done the handler setup.
    - */
    tracehook_signal_handler(signr, &info, &ka, regs,
    - test_thread_flag(TIF_SINGLE_STEP));
    + current->thread.per_info.single_step);
    }
    return;
    }


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