Re: [PATCH 3/4] kernel: add support for TIF_NOTIFY_SIGNAL

Jens Axboe
2020-10-14T09:30:30Z

On 10/13/20 5:42 PM, Thomas Gleixner wrote:
> On Thu, Oct 08 2020 at 09:27, Jens Axboe wrote:
>> This adds TIF_NOTIFY_SIGNAL handling in the generic code, which if set,
>> will return true if signal_pending() is used in a wait loop. That causes
>> an exit of the loop so that notify_signal tracehooks can be run. If the
>> wait loop is currently inside a system call, the system call is restarted
>> once task_work has been processed.
>>
>> x86 is using the generic entry code, add the necessary TIF_NOTIFY_SIGNAL
>> definitions for it.
>
> Can you please split that into core changes and a patch which adds
> support for x86?

Sure, I'll split it into generic and then x86 after that.

>> static inline int signal_pending(struct task_struct *p)
>> {
>> +#ifdef TIF_NOTIFY_SIGNAL
>
> As I said in the other thread, plase make this
>
> #if defined(CONFIG_GENERIC_ENTRY) && defined(TIF_NOTIFY_SIGNAL)

Thanks, I'll make those tweaks.

> Other than that, this approach of using arch_do_signal() addresses my
> earlier concerns about the syscall restart machinery.

Great! Thanks for taking a look.

--
Jens Axboe