Re: [PATCH 1/2] futex: adjust a futex timeout with a per-timens offset

[Dmitry Safonov]

On 10/15/20 8:29 AM, Andrei Vagin wrote:
> For all commands except FUTEX_WAIT, timeout is interpreted as an
> absolute value. This absolute value is inside the task's time namespace
> and has to be converted to the host's time.
> 
> Cc: <sta...@vger.kernel.org>
> Fixes: 5a590f35add9 ("posix-clocks: Wire up clock_gettime() with timens 
> offsets")
> Reported-by: Hans van der Laan <j.h.vanderl...@student.utwente.nl>
> Signed-off-by: Andrei Vagin <ava...@gmail.com>[..]
> @@ -3797,6 +3798,8 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, 
> u32, val,
>               t = timespec64_to_ktime(ts);
>               if (cmd == FUTEX_WAIT)
>                       t = ktime_add_safe(ktime_get(), t);
> +             else if (!(cmd & FUTEX_CLOCK_REALTIME))
> +                     t = timens_ktime_to_host(CLOCK_MONOTONIC, t);

Err, it probably should be
: else if (!(op & FUTEX_CLOCK_REALTIME))

And there's also
: SYSCALL_DEFINE6(futex_time32, ...)
which wants to be patched.

Thanks,
          Dmitry