Re: [PATCH 11/19] usb: typec: tcpm: don't wait for the VDM discovery work

[sashiko-bot@kernel.org]

> From: Josef Bacik <josef@toxicpanda.com>
> 
> mod_vdm_discovery_cancel_delayed_work() calls kthread_cancel_work_sync()
> with port->lock held, and tcpm_vdm_discovery_work() starts by taking
> that lock.  This is fine as long as the caller runs on the kthread
> worker of the port, like the work.  But tcpm_reset_port() is also
> reached from tcpm_tcpc_reset(), which tcpci_irq() calls from its
> interrupt thread.  If the work is running, it waits for the lock while
> the holder of the lock waits for the work.
> 
> Use a flag instead, protected by port->lock, which is set when the work
> is scheduled and cleared when it is cancelled.  The work returns at once
> if the flag is not set.
> 
> tcpm_unregister_port() calls tcpm_reset_port() after it has destroyed
> the worker.  Commit 98d00deb6ae4 ("usb: typec: tcpm: fix use-after-free
> of the kthread worker on port unregister") put a test of port->wq in
> front of the cancel for that case.  Nothing is cancelled any more, so
> the test goes.
> 
> Fixes: 205dc9cb39f5 ("usb: typec: tcpm: implement retry mechanism for Discover Identity VDMs")
> Cc: stable <stable@kernel.org>
> Cc: Badhri Jagan Sridharan <badhri@google.com>
> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261027-llm-usb-v1-0-b9751ddb9c7c@linuxfoundation.org?part=11