On Thu, Dec 29, 2016 at 03:56:14PM +0800, tang.junhui@xxxxxxxxxx wrote:
> From: "tang.junhui" <tang.junhui@xxxxxxxxxx>
>
> SIGUSR2 is not blocked by default, it would cause bellow conflict
> in removing of the last path:
ACK
-Ben
> -------------------------------------------------------------
> uevent processing thread | waiter thread
> -----------------------------------------|-------------------
> uev_remove_path() | waiteventloop()
> lock(&vecs->lock) |
> ev_remove_path() |
> dm_queue_if_no_path()----------------|----> dm_task_run()
> flush_map() | |
> remove_map_and_stop_waiter() | -> pthread_cleanup_push(cleanup_lock, &waiter->vecs->lock);
> _remove_map() | lock(&waiter->vecs->lock)//wait for the locker
> stop_waiter_thread() |
> pthread_cancel(thread) |
> pthread_kill(thread,SIGUSR2)-|------> sigusr2 (int sig)
> | condlog()
> | fprintf() //it has test cancel point
> | cleanup_lock() //thread cancel, and pop, which unlock the
> | locker of uevent processing thread
> --------------------------------------------------------------
> Since SIGUSR2 is only needed when waiter thread running in dm_task_run(),
> and it has already been unblocked before dm_task_run(), so this patch block
> SIGUSR2 for other times.
>
> Change-Id: I8c46292dc954415764ebbe054498b4f7ea53c1c6
> Signed-off-by: tang.junhui <tang.junhui@xxxxxxxxxx>
> ---
> multipathd/main.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/multipathd/main.c b/multipathd/main.c
> index adc3258..fe69abd 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -2181,6 +2181,12 @@ sigusr2 (int sig)
> static void
> signal_init(void)
> {
> + sigset_t set;
> +
> + sigemptyset(&set);
> + sigaddset(&set, SIGUSR2);
> + pthread_sigmask(SIG_SETMASK, &set, NULL);
> +
> signal_set(SIGHUP, sighup);
> signal_set(SIGUSR1, sigusr1);
> signal_set(SIGUSR2, sigusr2);
> --
> 2.8.1.windows.1
>
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
