HID: hid-bigbenff: fix race condition for scheduled work during removal
authorHanno Zulla <kontakt@hanno.de>
Tue, 18 Feb 2020 11:39:31 +0000 (12:39 +0100)
committerBenjamin Tissoires <benjamin.tissoires@redhat.com>
Tue, 18 Feb 2020 13:43:51 +0000 (14:43 +0100)
It's possible that there is scheduled work left while the device is
already being removed, which can cause a kernel crash. Adding a flag
will avoid this.

Signed-off-by: Hanno Zulla <kontakt@hanno.de>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
drivers/hid/hid-bigbenff.c

index f8c552b..db6da21 100644 (file)
@@ -174,6 +174,7 @@ static __u8 pid0902_rdesc_fixed[] = {
 struct bigben_device {
        struct hid_device *hid;
        struct hid_report *report;
+       bool removed;
        u8 led_state;         /* LED1 = 1 .. LED4 = 8 */
        u8 right_motor_on;    /* right motor off/on 0/1 */
        u8 left_motor_force;  /* left motor force 0-255 */
@@ -190,6 +191,9 @@ static void bigben_worker(struct work_struct *work)
                struct bigben_device, worker);
        struct hid_field *report_field = bigben->report->field[0];
 
+       if (bigben->removed)
+               return;
+
        if (bigben->work_led) {
                bigben->work_led = false;
                report_field->value[0] = 0x01; /* 1 = led message */
@@ -304,6 +308,7 @@ static void bigben_remove(struct hid_device *hid)
 {
        struct bigben_device *bigben = hid_get_drvdata(hid);
 
+       bigben->removed = true;
        cancel_work_sync(&bigben->worker);
        hid_hw_stop(hid);
 }
@@ -324,6 +329,7 @@ static int bigben_probe(struct hid_device *hid,
                return -ENOMEM;
        hid_set_drvdata(hid, bigben);
        bigben->hid = hid;
+       bigben->removed = false;
 
        error = hid_parse(hid);
        if (error) {