linux-kernel - Re: [PATCH] usb: usbfs: Add reset

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <f159e37f-3b27-4977-9712-345e8902eb48@rowland.harvard.edu>
Date: Fri, 22 Aug 2025 16:30:18 -0400
From: Alan Stern <stern@...land.harvard.edu>
To: ccc194101@....com
Cc: gregkh@...uxfoundation.org, jannh@...gle.com, rex.nie@...uarmicro.com,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	chenchangcheng <chenchangcheng@...inos.cn>
Subject: Re: [PATCH] usb: usbfs: Add reset_resume callback to usbfs.

On Fri, Aug 22, 2025 at 10:46:02AM +0800, ccc194101@....com wrote:
> From: chenchangcheng <chenchangcheng@...inos.cn>
> 
> When an Apple device is inserted into the host, and the host
> wakes up from S3/S4 power states, if the reset_resume process
> is triggered, the absence of a reset_resume callback in usbfs will
> cause the device to unbind.
> By adding a reset_resume callback to usbfs and reporting REMOVE and ADD
> uevents in reset_resume, the userspace is prompted to reissue commands
> to re-establish the binding with usbfs.

usbfs has no way to inform userspace when the device is reset.  This is 
true for normal resets as well as for reset-resumes (no pre_reset, 
post_reset, or reset_resume callbacks).  I don't see any point in trying 
to add support for the latter but not the former.

Unbinding the device forces userspace to re-open the device file and 
establish a new binding.  How does adding REMOVE and ADD uevents make 
the situation any better than it already is?

Alan Stern