Re: [PATCH 0/2] io_uring: honour submitter's time namespace for ABS timeouts

[Pavel Begunkov <asml.silence@gmail.com>]

On 5/4/26 16:37, Maoyi Xie wrote:
> This series addresses two io_uring code paths that arm an ABS
> hrtimer from a timestamp supplied by the caller. Both paths skip
> the conversion from the submitter's time namespace view to host
> view via timens_ktime_to_host(). The clock is CLOCK_MONOTONIC by
> default, or optionally CLOCK_BOOTTIME.
> 
> All four other ABS timer interfaces already do this conversion:
> timer_settime(TIMER_ABSTIME), clock_nanosleep(TIMER_ABSTIME),
> alarm_timer_nsleep(TIMER_ABSTIME), and
> timerfd_settime(TFD_TIMER_ABSTIME).
> 
> Patch 1/2 (io_uring/timeout) covers IORING_OP_TIMEOUT and
> IORING_OP_LINK_TIMEOUT via io_parse_user_time(). It is essentially
> the draft Pavel posted on the original thread. I rebased it on
> io_uring-7.1 and verified end to end.
> 
> Patch 2/2 (io_uring/wait) covers the IORING_ENTER_ABS_TIMER path
> in io_uring_enter(). That path parses ext_arg->ts inline rather
> than going through io_parse_user_time(). Patch 1/2 therefore does
> not cover it.
> 
> Per Pavel and Jens's discussion on the original thread, the two
> sites use two direct timens_ktime_to_host() call sites rather
> than a shared helper. Patch 1/2 also splits the existing
> io_timeout_get_clock() into a flags only io_flags_to_clock(), so
> io_parse_user_time() can resolve the clock without a
> struct io_timeout_data.
> 
> SQPOLL is automatically covered. The SQPOLL kernel thread is
> created via create_io_thread() with CLONE_THREAD and no CLONE_NEW*
> flag. copy_namespaces() therefore shares the submitter's nsproxy
> by reference. timens_ktime_to_host() through "current" sees the
> submitter's time_ns when called from the SQPOLL kthread. PoCs for
> both paths confirm this.

At a quick glance, both look good. I think you had an isolated
reproducer, are you sending it as a liburing test? Would be
greatly appreciated.

-- 
Pavel Begunkov