USB: serial: keyspan: fix memleak on probe errors

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

unreferenced object 0xffff888258228440 (size 64):
  comm "kworker/7:2", pid 2005, jiffies 4294989509 (age 824.540s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8167939c>] slab_post_alloc_hook+0x9c/0x490
    [<ffffffff8167f627>] kmem_cache_alloc_trace+0x1f7/0x470
    [<ffffffffa02ac0e4>] keyspan_port_probe+0xa4/0x5d0 [keyspan]
    [<ffffffffa0294c07>] usb_serial_device_probe+0x97/0x1d0 [usbserial]
    [<ffffffff82b50ca7>] really_probe+0x167/0x460
    [<ffffffff82b51099>] __driver_probe_device+0xf9/0x180
    [<ffffffff82b51173>] driver_probe_device+0x53/0x130
    [<ffffffff82b516f5>] __device_attach_driver+0x105/0x130
    [<ffffffff82b4cfe9>] bus_for_each_drv+0x129/0x190
    [<ffffffff82b50a69>] __device_attach+0x1c9/0x270
    [<ffffffff82b518d0>] device_initial_probe+0x20/0x30
    [<ffffffff82b4f062>] bus_probe_device+0x142/0x160
    [<ffffffff82b4a4e9>] device_add+0x829/0x1300
    [<ffffffffa0295fda>] usb_serial_probe.cold+0xc9b/0x14ac [usbserial]
    [<ffffffffa02266aa>] usb_probe_interface+0x1aa/0x3c0 [usbcore]
    [<ffffffff82b50ca7>] really_probe+0x167/0x460

If keyspan_port_probe() fails to allocate memory for an out_buffer[i] or
in_buffer[i], the previously allocated memory for out_buffer or
in_buffer needs to be freed on the error handling path, otherwise a
memory leak will result.

Fixes: bad41a5 ("USB: keyspan: fix port DMA-buffer allocations")
Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Wang Hai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: [email protected]      # 3.12
Signed-off-by: Johan Hovold <[email protected]>

Author: Wang Hai

drivers/usb/serial/keyspan.c

@@ -2890,22 +2890,22 @@ static int keyspan_port_probe(struct usb_serial_port *port)
 	for (i = 0; i < ARRAY_SIZE(p_priv->in_buffer); ++i) {
 		p_priv->in_buffer[i] = kzalloc(IN_BUFLEN, GFP_KERNEL);
 		if (!p_priv->in_buffer[i])
-			goto err_in_buffer;
+			goto err_free_in_buffer;
 	}
 
 	for (i = 0; i < ARRAY_SIZE(p_priv->out_buffer); ++i) {
 		p_priv->out_buffer[i] = kzalloc(OUT_BUFLEN, GFP_KERNEL);
 		if (!p_priv->out_buffer[i])
-			goto err_out_buffer;
+			goto err_free_out_buffer;
 	}
 
 	p_priv->inack_buffer = kzalloc(INACK_BUFLEN, GFP_KERNEL);
 	if (!p_priv->inack_buffer)
-		goto err_inack_buffer;
+		goto err_free_out_buffer;
 
 	p_priv->outcont_buffer = kzalloc(OUTCONT_BUFLEN, GFP_KERNEL);
 	if (!p_priv->outcont_buffer)
-		goto err_outcont_buffer;
+		goto err_free_inack_buffer;
 
 	p_priv->device_details = d_details;
 
@@ -2951,15 +2951,14 @@ static int keyspan_port_probe(struct usb_serial_port *port)
 
 	return 0;
 
-err_outcont_buffer:
+err_free_inack_buffer:
 	kfree(p_priv->inack_buffer);
-err_inack_buffer:
+err_free_out_buffer:
 	for (i = 0; i < ARRAY_SIZE(p_priv->out_buffer); ++i)
 		kfree(p_priv->out_buffer[i]);
-err_out_buffer:
+err_free_in_buffer:
 	for (i = 0; i < ARRAY_SIZE(p_priv->in_buffer); ++i)
 		kfree(p_priv->in_buffer[i]);
-err_in_buffer:
 	kfree(p_priv);
 
 	return -ENOMEM;