Re: Re: Subject: [PATCH v1] USB:Core: BugFix: Proper handling of Race Condition when two USB class drivers try to call init_usb_class simultaneously

From: gregkh@xxxxxxxxxxxxxxxxxxx
Date: Tue Jan 31 2017 - 02:01:13 EST

Q: Were do I find info about this thing called top-posting?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

A: No.
Q: Should I include quotations after my reply?

On Tue, Jan 31, 2017 at 05:21:46AM +0000, Ajay Kaher wrote:
> At boot time, probe function of multiple connected devices
> (proprietary devices) execute simultaneously.

What exactly do you mean here? How can probe happen "simultaneously"?
The USB core prevents this, right?

And what do you mean exactly by "(proprietary devices)"?

> And because of the following code path race condition happens:
> probe->usb_register_dev->init_usb_class

Why is this just showing up now, and hasn't been an issue for the decade
or so this code has been around? What changed?

> Tested with these changes, and problem has been solved.

What changes?


greg k-h