linux-kernel - Re: [PATCH 06/10] Revert "usb: typec: displayport: Receive DP Status Update NAK request exit dp altmode"

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

Message-ID: <2025061623-ammonium-outskirts-e89e@gregkh>
Date: Mon, 16 Jun 2025 16:15:06 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Andrei Kuchynski <akuchynski@...omium.org>
Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Dmitry Baryshkov <lumag@...nel.org>,
	Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
	Jameson Thies <jthies@...gle.com>,
	Benson Leung <bleung@...omium.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>,
	Guenter Roeck <groeck@...omium.org>,
	Pooja Katiyar <pooja.katiyar@...el.com>,
	Badhri Jagan Sridharan <badhri@...gle.com>,
	RD Babiera <rdbabiera@...gle.com>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, chrome-platform@...ts.linux.dev
Subject: Re: [PATCH 06/10] Revert "usb: typec: displayport: Receive DP Status
 Update NAK request exit dp altmode"

On Mon, Jun 16, 2025 at 01:31:43PM +0000, Andrei Kuchynski wrote:
> This reverts commit b4b38ffb38c91afd4dc387608db26f6fc34ed40b.
> 
> The commit introduced a deadlock with the cros_ec_typec driver.
> The deadlock occurs due to a recursive lock acquisition of
> `cros_typec_altmode_work::mutex`.
> The call chain is as follows: 
> 1. cros_typec_altmode_work() acquires the mutex
> 2. typec_altmode_vdm() -> dp_altmode_vdm() ->
> 3. typec_altmode_exit() -> cros_typec_altmode_exit()
> 4. cros_typec_altmode_exit() attempts to acquire the mutex again
> 
> This revert is considered safe as no other known driver sends back
> DP_CMD_STATUS_UPDATE command with the NAK flag.
> 
> Signed-off-by: Andrei Kuchynski <akuchynski@...omium.org>
> ---
>  drivers/usb/typec/altmodes/displayport.c | 4 ----
>  1 file changed, 4 deletions(-)

Why isn't this being sent as a separate patch for 6.16-final?  And why
not put a fixes: line?

thanks,

greg k-h