[PATCH 5.8 239/255] usb: typec: ucsi: Fix 2 unlocked ucsi_run_command calls

From: Greg Kroah-Hartman
Date: Tue Sep 01 2020 - 11:51:27 EST


From: Hans de Goede <hdegoede@xxxxxxxxxx>

commit 7e90057f125c8c852940b848e06e7a72f050fc6f upstream.

Fix 2 unlocked ucsi_run_command calls:

1. ucsi_handle_connector_change() contains one ucsi_send_command() call,
which takes the ppm_lock for it; and one ucsi_run_command() call which
relies on the caller have taking the ppm_lock.
ucsi_handle_connector_change() does not take the lock, so the
second (ucsi_run_command) calls should also be ucsi_send_command().

2. ucsi_get_pdos() gets called from ucsi_handle_connector_change() which
does not hold the ppm_lock, so it also must use ucsi_send_command().

This commit also adds a WARN_ON(!mutex_is_locked(&ucsi->ppm_lock)); to
ucsi_run_command() to avoid similar problems getting re-introduced in
the future.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200809141904.4317-3-hdegoede@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/usb/typec/ucsi/ucsi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -152,6 +152,8 @@ static int ucsi_run_command(struct ucsi
u8 length;
int ret;

+ WARN_ON(!mutex_is_locked(&ucsi->ppm_lock));
+
ret = ucsi_exec_command(ucsi, command);
if (ret < 0)
return ret;
@@ -502,7 +504,7 @@ static void ucsi_get_pdos(struct ucsi_co
command |= UCSI_GET_PDOS_PARTNER_PDO(is_partner);
command |= UCSI_GET_PDOS_NUM_PDOS(UCSI_MAX_PDOS - 1);
command |= UCSI_GET_PDOS_SRC_PDOS;
- ret = ucsi_run_command(ucsi, command, con->src_pdos,
+ ret = ucsi_send_command(ucsi, command, con->src_pdos,
sizeof(con->src_pdos));
if (ret < 0) {
dev_err(ucsi->dev, "UCSI_GET_PDOS failed (%d)\n", ret);
@@ -681,7 +683,7 @@ static void ucsi_handle_connector_change
*/
command = UCSI_GET_CAM_SUPPORTED;
command |= UCSI_CONNECTOR_NUMBER(con->num);
- ucsi_run_command(con->ucsi, command, NULL, 0);
+ ucsi_send_command(con->ucsi, command, NULL, 0);
}

if (con->status.change & UCSI_CONSTAT_PARTNER_CHANGE)