[PATCH 2/4] usb: typec: ucsi: Fix 2 unlocked ucsi_run_command calls - Linux-stable-mirror

9 Aug 2020

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@vger.kernel.org
Signed-off-by: Hans de Goede hdegoede@redhat.com
---
 drivers/usb/typec/ucsi/ucsi.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index d9d93f83b2a6..2f586d6c54f4 100644
--- 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 *ucsi, u64 command,
    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_connector *con, int is_partner)
    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(struct work_struct *work)
    	 */
    	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)
-- 
2.26.2


    