Re: [PATCH v4] mm,hwpoison: Differentiate Action Required error in current and non current processes

["HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>]

It's desirable that $SUBJECT represents what that patch does, so
how about something like
"mm, hwpoison: send SIGBUS to PF_MCE_EARLY processes on action required events" ?

On Wed, Jan 20, 2021 at 03:03:02PM +0800, Aili Yao wrote:
> When a memory uncorrected error is triggered by process A who accessed
> the address with error; It's Action Required Case for only current
> process which triggered this.this Action Required case means Action
> optional to other process who share the same page. Usually, kill current
> process will be sufficient, other process sharing the same page will
> get be signaled when they really touch the poisoned page.
> 
> But there is another scenario that other processes
> sharing the same page want to be signaled early with PF_MCE_EARLY set,
> In this case, we should get them into kill list and signal
> BUS_MCEERR_AO to them.
> 
> So in this patch, task_early_kill will check current process if
> force_early is set, and if not current,check find_early_kill_thread
> to see if there is PF_MCE_EARLY process which cares the error.
> 
> In kill_proc, BUS_MCEERR_AR is only send to current, other process in
> kill list will be signaled BUS_MCEERR_AO.
> 
> Signed-off-by: Aili Yao <yaoaili@kingsoft.com>
...
> @@ -440,10 +443,13 @@ static struct task_struct *find_early_kill_thread(struct task_struct *tsk)
>   * Determine whether a given process is "early kill" process which expects
>   * to be signaled when some page under the process is hwpoisoned.
>   * Return task_struct of the dedicated thread (main thread unless explicitly
> - * specified) if the process is "early kill," and otherwise returns NULL.
> + * specified) if the process is "early kill" and otherwise returns NULL.
>   *
> - * Note that the above is true for Action Optional case, but not for Action
> - * Required case where SIGBUS should sent only to the current thread.
> + * Note that the above is true for Action Optional case. For Action Required
> + * case, it's only meaningful to the current thread which need to be signaled
> + * with SIGBUS, this error is Action Optional for other non current
> + * processes sharing the same error page,if the process is "early kill",the

Please insert a whitespace after commas (just for convention).

With these fixed, I agree with this patch.

Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>