ptp: Fix possible memory leak in ptp_clock_register()

I got memory leak as follows when doing fault injection test:

unreferenced object 0xffff88800906c618 (size 8):
  comm "i2c-idt82p33931", pid 4421, jiffies 4294948083 (age 13.188s)
  hex dump (first 8 bytes):
    70 74 70 30 00 00 00 00                          ptp0....
  backtrace:
    [<00000000312ed458>] __kmalloc_track_caller+0x19f/0x3a0
    [<0000000079f6e2ff>] kvasprintf+0xb5/0x150
    [<0000000026aae54f>] kvasprintf_const+0x60/0x190
    [<00000000f323a5f7>] kobject_set_name_vargs+0x56/0x150
    [<000000004e35abdd>] dev_set_name+0xc0/0x100
    [<00000000f20cfe25>] ptp_clock_register+0x9f4/0xd30 [ptp]
    [<000000008bb9f0de>] idt82p33_probe.cold+0x8b6/0x1561 [ptp_idt82p33]

When posix_clock_register() returns an error, the name allocated
in dev_set_name() will be leaked, the put_device() should be used
to give up the device reference, then the name will be freed in
kobject_cleanup() and other memory will be freed in ptp_clock_release().

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: a33121e ("ptp: fix the race between the release of ptp_clock and cdev")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/ptp/ptp_clock.c

@@ -283,15 +283,22 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	/* Create a posix clock and link it to the device. */
 	err = posix_clock_register(&ptp->clock, &ptp->dev);
 	if (err) {
+	        if (ptp->pps_source)
+	                pps_unregister_source(ptp->pps_source);
+
+		kfree(ptp->vclock_index);
+
+		if (ptp->kworker)
+	                kthread_destroy_worker(ptp->kworker);
+
+		put_device(&ptp->dev);
+
 		pr_err("failed to create posix clock\n");
-		goto no_clock;
+		return ERR_PTR(err);
 	}
 
 	return ptp;
 
-no_clock:
-	if (ptp->pps_source)
-		pps_unregister_source(ptp->pps_source);
 no_pps:
 	ptp_cleanup_pin_groups(ptp);
 no_pin_groups: