[PATCH] usb: core: port: Deattach Type-C connector on component unbind

[PATCH] usb: core: port: Deattach Type-C connector on component unbind

[Chia-Lin Kao (AceLan)]

connector_unbind() is the mirror of connector_bind(), but it is missing
the symmetric call to typec_deattach() that connector_bind() makes via:

    if (port_dev->child)
        typec_attach(port_dev->connector, &port_dev->child->dev);

When a Thunderbolt dock is unplugged, two teardown paths race:

1. The component framework calls connector_unbind() first, which sets
   port_dev->connector = NULL without calling typec_deattach().  This
   leaves port->usb2_dev/port->usb3_dev in struct typec_port pointing at
   the USB device that is about to be freed.

2. usb_disconnect() then calls typec_deattach(port_dev->connector, ...),
   but port_dev->connector is already NULL, so the call is a no-op and
   port->usb2_dev is never cleared.

3. Concurrently, UCSI detects a PD partner-disconnect event and calls
   typec_unregister_partner(), which reads port->usb2_dev (now a dangling
   pointer to freed memory) and passes it to typec_partner_unlink_device()
   -> sysfs_remove_link() -> dev_name() on the freed device, corrupting
   the typec/UCSI partner state.

This corruption leaves the Thunderbolt tunnel in an inconsistent state on
the next dock hot-plug.  On affected hardware the dock's I225/igc NIC fails
to enumerate: AER fires a slot reset while the igc driver is still
initialising ("PCIe link lost"), and the subsequent igc_reset attempt hits
igc_rd32 on an already-detached device:

    igc 0000:2e:00.0 eth0: PCIe link lost, device now detached
    igc: Failed to read reg 0x0!
    WARNING: CPU: 9 PID: 129 at drivers/net/ethernet/intel/igc/igc_main.c:7005
             igc_rd32+0xa4/0xc0 [igc]
    Call Trace:
     igc_disable_pcie_master+0x16/0xa0 [igc]
     igc_reset_hw_base+0x14/0x170 [igc]
     igc_reset+0x63/0x110 [igc]
     igc_io_slot_reset+0x9e/0xd0 [igc]
     report_slot_reset+0x5d/0xc0
     pcie_do_recovery+0x209/0x400
     aer_isr_one_error_type+0x235/0x430
     aer_isr+0x4e/0x80
     irq_thread+0xf4/0x1f0

4. UCSI later handles the PD partner-disconnect and calls
   typec_unregister_partner(), which still sees the stale port->usb2_dev
   and tries to remove its sysfs link a second time:

   kernfs: can not remove 'typec', no directory
   WARNING: CPU: 6 PID: 55 at fs/kernfs/dir.c:1706 kernfs_remove_by_name_ns+0xe9/0xf0
   Workqueue: events ucsi_handle_connector_change [typec_ucsi]
   Call Trace:
    sysfs_remove_link+0x19/0x50
    typec_unregister_partner+0x6e/0x120 [typec]
    ucsi_unregister_partner+0x107/0x150 [typec_ucsi]
    ucsi_handle_connector_change+0x3ec/0x490 [typec_ucsi]
    process_one_work+0x18e/0x3e0
    worker_thread+0x2e3/0x420
    kthread+0x10a/0x230
    ret_from_fork+0x121/0x140
    ret_from_fork_asm+0x1a/0x30

   With worse timing the same stale pointer is dereferenced after the
   backing memory is freed, turning the warning into a use-after-free.

Fix the asymmetry: call typec_deattach() before clearing
port_dev->connector, matching what connector_bind() does on the bind side.
typec_partner_deattach() is already protected by port->partner_link_lock,
so it serialises safely with the concurrent typec_unregister_partner() path.

Fixes: 11110783f5ea ("usb: Inform the USB Type-C class about enumerated devices")
Cc: stable@vger.kernel.org
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
---
 drivers/usb/core/port.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index b1364f0c384ce..b4452b665f591 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -740,6 +740,8 @@ static void connector_unbind(struct device *dev, struct device *connector, void
 
 	sysfs_remove_link(&connector->kobj, dev_name(dev));
 	sysfs_remove_link(&dev->kobj, "connector");
+	if (port_dev->child)
+		typec_deattach(port_dev->connector, &port_dev->child->dev);
 	port_dev->connector = NULL;
 }
 
-- 
2.53.0

Re: [PATCH] usb: core: port: Deattach Type-C connector on component unbind

[AceLan Kao]

Chia-Lin Kao (AceLan) <acelan.kao@canonical.com> 於 2026年6月11日週四 下午3:12寫道：
>
> connector_unbind() is the mirror of connector_bind(), but it is missing
> the symmetric call to typec_deattach() that connector_bind() makes via:
>
>     if (port_dev->child)
>         typec_attach(port_dev->connector, &port_dev->child->dev);
>
> When a Thunderbolt dock is unplugged, two teardown paths race:
>
> 1. The component framework calls connector_unbind() first, which sets
>    port_dev->connector = NULL without calling typec_deattach().  This
>    leaves port->usb2_dev/port->usb3_dev in struct typec_port pointing at
>    the USB device that is about to be freed.
>
> 2. usb_disconnect() then calls typec_deattach(port_dev->connector, ...),
>    but port_dev->connector is already NULL, so the call is a no-op and
>    port->usb2_dev is never cleared.
>
> 3. Concurrently, UCSI detects a PD partner-disconnect event and calls
>    typec_unregister_partner(), which reads port->usb2_dev (now a dangling
>    pointer to freed memory) and passes it to typec_partner_unlink_device()
>    -> sysfs_remove_link() -> dev_name() on the freed device, corrupting
>    the typec/UCSI partner state.
>
> This corruption leaves the Thunderbolt tunnel in an inconsistent state on
> the next dock hot-plug.  On affected hardware the dock's I225/igc NIC fails
> to enumerate: AER fires a slot reset while the igc driver is still
> initialising ("PCIe link lost"), and the subsequent igc_reset attempt hits
> igc_rd32 on an already-detached device:
>
>     igc 0000:2e:00.0 eth0: PCIe link lost, device now detached
>     igc: Failed to read reg 0x0!
>     WARNING: CPU: 9 PID: 129 at drivers/net/ethernet/intel/igc/igc_main.c:7005
>              igc_rd32+0xa4/0xc0 [igc]
>     Call Trace:
>      igc_disable_pcie_master+0x16/0xa0 [igc]
>      igc_reset_hw_base+0x14/0x170 [igc]
>      igc_reset+0x63/0x110 [igc]
>      igc_io_slot_reset+0x9e/0xd0 [igc]
>      report_slot_reset+0x5d/0xc0
>      pcie_do_recovery+0x209/0x400
>      aer_isr_one_error_type+0x235/0x430
>      aer_isr+0x4e/0x80
>      irq_thread+0xf4/0x1f0
>
> 4. UCSI later handles the PD partner-disconnect and calls
>    typec_unregister_partner(), which still sees the stale port->usb2_dev
>    and tries to remove its sysfs link a second time:
>
>    kernfs: can not remove 'typec', no directory
>    WARNING: CPU: 6 PID: 55 at fs/kernfs/dir.c:1706 kernfs_remove_by_name_ns+0xe9/0xf0
>    Workqueue: events ucsi_handle_connector_change [typec_ucsi]
>    Call Trace:
>     sysfs_remove_link+0x19/0x50
>     typec_unregister_partner+0x6e/0x120 [typec]
>     ucsi_unregister_partner+0x107/0x150 [typec_ucsi]
>     ucsi_handle_connector_change+0x3ec/0x490 [typec_ucsi]
>     process_one_work+0x18e/0x3e0
>     worker_thread+0x2e3/0x420
>     kthread+0x10a/0x230
>     ret_from_fork+0x121/0x140
>     ret_from_fork_asm+0x1a/0x30
>
>    With worse timing the same stale pointer is dereferenced after the
>    backing memory is freed, turning the warning into a use-after-free.
>
> Fix the asymmetry: call typec_deattach() before clearing
> port_dev->connector, matching what connector_bind() does on the bind side.
> typec_partner_deattach() is already protected by port->partner_link_lock,
> so it serialises safely with the concurrent typec_unregister_partner() path.
>
> Fixes: 11110783f5ea ("usb: Inform the USB Type-C class about enumerated devices")
> Cc: stable@vger.kernel.org
> Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
> ---
>  drivers/usb/core/port.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
> index b1364f0c384ce..b4452b665f591 100644
> --- a/drivers/usb/core/port.c
> +++ b/drivers/usb/core/port.c
> @@ -740,6 +740,8 @@ static void connector_unbind(struct device *dev, struct device *connector, void
>
>         sysfs_remove_link(&connector->kobj, dev_name(dev));
>         sysfs_remove_link(&dev->kobj, "connector");
> +       if (port_dev->child)
> +               typec_deattach(port_dev->connector, &port_dev->child->dev);
>         port_dev->connector = NULL;
>  }
>
> --
> 2.53.0
>

Hi,

Just a gentle ping, please help to review this path.
Thanks.

Re: [PATCH] usb: core: port: Deattach Type-C connector on component unbind

[Greg Kroah-Hartman]

On Thu, Jul 02, 2026 at 10:26:39AM +0800, AceLan Kao wrote:
> Chia-Lin Kao (AceLan) <acelan.kao@canonical.com> 於 2026年6月11日週四 下午3:12寫道：
> >
> > connector_unbind() is the mirror of connector_bind(), but it is missing
> > the symmetric call to typec_deattach() that connector_bind() makes via:
> >
> >     if (port_dev->child)
> >         typec_attach(port_dev->connector, &port_dev->child->dev);
> >
> > When a Thunderbolt dock is unplugged, two teardown paths race:
> >
> > 1. The component framework calls connector_unbind() first, which sets
> >    port_dev->connector = NULL without calling typec_deattach().  This
> >    leaves port->usb2_dev/port->usb3_dev in struct typec_port pointing at
> >    the USB device that is about to be freed.
> >
> > 2. usb_disconnect() then calls typec_deattach(port_dev->connector, ...),
> >    but port_dev->connector is already NULL, so the call is a no-op and
> >    port->usb2_dev is never cleared.
> >
> > 3. Concurrently, UCSI detects a PD partner-disconnect event and calls
> >    typec_unregister_partner(), which reads port->usb2_dev (now a dangling
> >    pointer to freed memory) and passes it to typec_partner_unlink_device()
> >    -> sysfs_remove_link() -> dev_name() on the freed device, corrupting
> >    the typec/UCSI partner state.
> >
> > This corruption leaves the Thunderbolt tunnel in an inconsistent state on
> > the next dock hot-plug.  On affected hardware the dock's I225/igc NIC fails
> > to enumerate: AER fires a slot reset while the igc driver is still
> > initialising ("PCIe link lost"), and the subsequent igc_reset attempt hits
> > igc_rd32 on an already-detached device:
> >
> >     igc 0000:2e:00.0 eth0: PCIe link lost, device now detached
> >     igc: Failed to read reg 0x0!
> >     WARNING: CPU: 9 PID: 129 at drivers/net/ethernet/intel/igc/igc_main.c:7005
> >              igc_rd32+0xa4/0xc0 [igc]
> >     Call Trace:
> >      igc_disable_pcie_master+0x16/0xa0 [igc]
> >      igc_reset_hw_base+0x14/0x170 [igc]
> >      igc_reset+0x63/0x110 [igc]
> >      igc_io_slot_reset+0x9e/0xd0 [igc]
> >      report_slot_reset+0x5d/0xc0
> >      pcie_do_recovery+0x209/0x400
> >      aer_isr_one_error_type+0x235/0x430
> >      aer_isr+0x4e/0x80
> >      irq_thread+0xf4/0x1f0
> >
> > 4. UCSI later handles the PD partner-disconnect and calls
> >    typec_unregister_partner(), which still sees the stale port->usb2_dev
> >    and tries to remove its sysfs link a second time:
> >
> >    kernfs: can not remove 'typec', no directory
> >    WARNING: CPU: 6 PID: 55 at fs/kernfs/dir.c:1706 kernfs_remove_by_name_ns+0xe9/0xf0
> >    Workqueue: events ucsi_handle_connector_change [typec_ucsi]
> >    Call Trace:
> >     sysfs_remove_link+0x19/0x50
> >     typec_unregister_partner+0x6e/0x120 [typec]
> >     ucsi_unregister_partner+0x107/0x150 [typec_ucsi]
> >     ucsi_handle_connector_change+0x3ec/0x490 [typec_ucsi]
> >     process_one_work+0x18e/0x3e0
> >     worker_thread+0x2e3/0x420
> >     kthread+0x10a/0x230
> >     ret_from_fork+0x121/0x140
> >     ret_from_fork_asm+0x1a/0x30
> >
> >    With worse timing the same stale pointer is dereferenced after the
> >    backing memory is freed, turning the warning into a use-after-free.
> >
> > Fix the asymmetry: call typec_deattach() before clearing
> > port_dev->connector, matching what connector_bind() does on the bind side.
> > typec_partner_deattach() is already protected by port->partner_link_lock,
> > so it serialises safely with the concurrent typec_unregister_partner() path.
> >
> > Fixes: 11110783f5ea ("usb: Inform the USB Type-C class about enumerated devices")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
> > ---
> >  drivers/usb/core/port.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
> > index b1364f0c384ce..b4452b665f591 100644
> > --- a/drivers/usb/core/port.c
> > +++ b/drivers/usb/core/port.c
> > @@ -740,6 +740,8 @@ static void connector_unbind(struct device *dev, struct device *connector, void
> >
> >         sysfs_remove_link(&connector->kobj, dev_name(dev));
> >         sysfs_remove_link(&dev->kobj, "connector");
> > +       if (port_dev->child)
> > +               typec_deattach(port_dev->connector, &port_dev->child->dev);
> >         port_dev->connector = NULL;
> >  }
> >
> > --
> > 2.53.0
> >
> 
> Hi,
> 
> Just a gentle ping, please help to review this path.

It was the merge window :(

Also, if you wish to have patches merged quicker, please provide review
comments on other patches while you wait, what is preventing that from
happening here?

thanks,

greg k-h