The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bed97b30968ba354035a020989df0623e52b5536 Mon Sep 17 00:00:00 2001

From: Hans de Goede hdegoede@redhat.com Date: Sun, 9 Aug 2020 16:19:04 +0200 Subject: [PATCH] usb: typec: ucsi: Hold con->lock for the entire duration of ucsi_register_port()

Commit 081da1325d35 ("usb: typec: ucsi: displayport: Fix a potential race during registration") made the ucsi code hold con->lock in ucsi_register_displayport(). But we really don't want any interactions with the connector to run before the port-registration process is fully complete.

This commit moves the taking of con->lock from ucsi_register_displayport() into ucsi_register_port() to achieve this.

Cc: stable@vger.kernel.org Fixes: 081da1325d35 ("usb: typec: ucsi: displayport: Fix a potential race during registration") Signed-off-by: Hans de Goede hdegoede@redhat.com Acked-by: Heikki Krogerus heikki.krogerus@linux.intel.com Reviewed-by: Guenter Roeck linux@roeck-us.net Link: https://lore.kernel.org/r/20200809141904.4317-5-hdegoede@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c index 048381c058a5..261131c9e37c 100644 --- a/drivers/usb/typec/ucsi/displayport.c +++ b/drivers/usb/typec/ucsi/displayport.c @@ -288,8 +288,6 @@ struct typec_altmode *ucsi_register_displayport(struct ucsi_connector *con, struct typec_altmode *alt; struct ucsi_dp *dp;

- mutex_lock(&con->lock); - /* We can't rely on the firmware with the capabilities. */ desc->vdo |= DP_CAP_DP_SIGNALING | DP_CAP_RECEPTACLE;

@@ -298,15 +296,12 @@ struct typec_altmode *ucsi_register_displayport(struct ucsi_connector *con, desc->vdo |= all_assignments << 16;

alt = typec_port_register_altmode(con->port, desc); - if (IS_ERR(alt)) { - mutex_unlock(&con->lock); + if (IS_ERR(alt)) return alt; - }

dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL); if (!dp) { typec_unregister_altmode(alt); - mutex_unlock(&con->lock); return ERR_PTR(-ENOMEM); }

@@ -319,7 +314,5 @@ struct typec_altmode *ucsi_register_displayport(struct ucsi_connector *con, alt->ops = &ucsi_displayport_ops; typec_altmode_set_drvdata(alt, dp);

- mutex_unlock(&con->lock); - return alt; } diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index 8a35144211e5..e680fcfdee60 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -898,12 +898,15 @@ static int ucsi_register_port(struct ucsi *ucsi, int index) con->num = index + 1; con->ucsi = ucsi;

+ /* Delay other interactions with the con until registration is complete */ + mutex_lock(&con->lock); + /* Get connector capability */ command = UCSI_GET_CONNECTOR_CAPABILITY; command |= UCSI_CONNECTOR_NUMBER(con->num); ret = ucsi_send_command(ucsi, command, &con->cap, sizeof(con->cap)); if (ret < 0) - return ret; + goto out;

if (con->cap.op_mode & UCSI_CONCAP_OPMODE_DRP) cap->data = TYPEC_PORT_DRD; @@ -935,26 +938,32 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)

ret = ucsi_register_port_psy(con); if (ret) - return ret; + goto out;

/* Register the connector */ con->port = typec_register_port(ucsi->dev, cap); - if (IS_ERR(con->port)) - return PTR_ERR(con->port); + if (IS_ERR(con->port)) { + ret = PTR_ERR(con->port); + goto out; + }

/* Alternate modes */ ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_CON); - if (ret) + if (ret) { dev_err(ucsi->dev, "con%d: failed to register alt modes\n", con->num); + goto out; + }

/* Get the status */ command = UCSI_GET_CONNECTOR_STATUS | UCSI_CONNECTOR_NUMBER(con->num); ret = ucsi_send_command(ucsi, command, &con->status, sizeof(con->status)); if (ret < 0) { dev_err(ucsi->dev, "con%d: failed to get status\n", con->num); - return 0; + ret = 0; + goto out; } + ret = 0; /* ucsi_send_command() returns length on success */

switch (UCSI_CONSTAT_PARTNER_TYPE(con->status.flags)) { case UCSI_CONSTAT_PARTNER_TYPE_UFP: @@ -979,17 +988,21 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)

if (con->partner) { ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP); - if (ret) + if (ret) { dev_err(ucsi->dev, "con%d: failed to register alternate modes\n", con->num); - else + ret = 0; + } else { ucsi_altmode_update_active(con); + } }

trace_ucsi_register_port(con->num, &con->status);

- return 0; +out: + mutex_unlock(&con->lock); + return ret; }

/**