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

[Andrei Kuchynski]

On Mon, Jun 16, 2025 at 4:15 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxx>
> > ---
> >  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?
>

Hi Greg,

The issue will emerge only after this series is applied, so 6.16
remains secure as this code is not executable.
I will submit it as a separate patch, with the relevant tags included.

Thanks,
Andrei