diff options
| author | RD Babiera <rdbabiera@google.com> | 2024-04-23 20:23:57 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-30 19:44:36 +0200 |
| commit | cdc9946ea6377e8e214b135ccc308c5e514ba25f (patch) | |
| tree | a7b6a94bae82d3d68a2f8416fc64f44516e99fc9 | |
| parent | 230ecdf71a644c9c73e0e6735b33173074ae3f94 (diff) | |
| download | linux-cdc9946ea6377e8e214b135ccc308c5e514ba25f.tar.gz | |
usb: typec: tcpm: enforce ready state when queueing alt mode vdm
Before sending Enter Mode for an Alt Mode, there is a gap between Discover
Modes and the Alt Mode driver queueing the Enter Mode VDM for the port
partner to send a message to the port.
If this message results in unregistering Alt Modes such as in a DR_SWAP,
then the following deadlock can occur with respect to the DisplayPort Alt
Mode driver:
1. The DR_SWAP state holds port->lock. Unregistering the Alt Mode driver
results in a cancel_work_sync() that waits for the current dp_altmode_work
to finish.
2. dp_altmode_work makes a call to tcpm_altmode_enter. The deadlock occurs
because tcpm_queue_vdm_unlock attempts to hold port->lock.
Before attempting to grab the lock, ensure that the port is in a state
vdm_run_state_machine can run in. Alt Mode unregistration will not occur
in these states.
Fixes: 03eafcfb60c0 ("usb: typec: tcpm: Add tcpm_queue_vdm_unlocked() helper")
Cc: stable@vger.kernel.org
Signed-off-by: RD Babiera <rdbabiera@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240423202356.3372314-2-rdbabiera@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/typec/tcpm/tcpm.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index 77e632ea68721..53c1f308ebd7c 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -1564,6 +1564,10 @@ static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header, static void tcpm_queue_vdm_unlocked(struct tcpm_port *port, const u32 header, const u32 *data, int cnt, enum tcpm_transmit_type tx_sop_type) { + if (port->state != SRC_READY && port->state != SNK_READY && + port->state != SRC_VDM_IDENTITY_REQUEST) + return; + mutex_lock(&port->lock); tcpm_queue_vdm(port, header, data, cnt, tx_sop_type); mutex_unlock(&port->lock); |