usb: typec: bus: verify partner exists in typec_altmode_attention

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commit f236433064 upstream.

Some usb hubs will negotiate DisplayPort Alt mode with the device
but will then negotiate a data role swap after entering the alt
mode. The data role swap causes the device to unregister all alt
modes, however the usb hub will still send Attention messages
even after failing to reregister the Alt Mode. type_altmode_attention
currently does not verify whether or not a device's altmode partner
exists, which results in a NULL pointer error when dereferencing
the typec_altmode and typec_altmode_ops belonging to the altmode
partner.

Verify the presence of a device's altmode partner before sending
the Attention message to the Alt Mode driver.

Fixes: 8a37d87d72 ("usb: typec: Bus type for alternate modes")
Cc: stable@vger.kernel.org
Signed-off-by: RD Babiera <rdbabiera@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230814180559.923475-1-rdbabiera@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

RD Babiera 2023-08-14 18:05:59 +00:00 • committed by Greg Kroah-Hartman

parent 31220bd89c

commit 0ad6bad31d

3 changed files with 13 additions and 4 deletions

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12

drivers/usb/typec/bus.c

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3

drivers/usb/typec/tcpm/tcpm.c

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2

include/linux/usb/typec_altmode.h

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