Re: [patch V4 part 1 05/36] x86/entry: Flip _TIF_SIGPENDING and _TIF_NOTIFY_RESUME handling

Alexandre Chartre
2020-05-06T13:08:42Z

On 5/5/20 3:16 PM, Thomas Gleixner wrote:
> Make sure task_work runs before any kind of userspace -- very much
> including signals -- is invoked.
>
> Suggested-by: Andy Lutomirski <luto@kernel.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/entry/common.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)

Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>

alex.

> --- a/arch/x86/entry/common.c
> +++ b/arch/x86/entry/common.c
> @@ -156,16 +156,16 @@ static void exit_to_usermode_loop(struct
> if (cached_flags & _TIF_PATCH_PENDING)
> klp_update_patch_state(current);
>
> - /* deal with pending signal delivery */
> - if (cached_flags & _TIF_SIGPENDING)
> - do_signal(regs);
> -
> if (cached_flags & _TIF_NOTIFY_RESUME) {
> clear_thread_flag(TIF_NOTIFY_RESUME);
> tracehook_notify_resume(regs);
> rseq_handle_notify_resume(NULL, regs);
> }
>
> + /* deal with pending signal delivery */
> + if (cached_flags & _TIF_SIGPENDING)
> + do_signal(regs);
> +
> if (cached_flags & _TIF_USER_RETURN_NOTIFY)
> fire_user_return_notifiers();
>
>