mt7601u: fix possible memory leak when the device is disconnected

When the device is disconnected while passing traffic it is possible
to receive out of order urbs causing a memory leak since the skb linked
to the current tx urb is not removed. Fix the issue deallocating the skb
cleaning up the tx ring. Moreover this patch fixes the following kernel
warning

[   57.480771] usb 1-1: USB disconnect, device number 2
[   57.483451] ------------[ cut here ]------------
[   57.483462] TX urb mismatch
[   57.483481] WARNING: CPU: 1 PID: 32 at drivers/net/wireless/mediatek/mt7601u/dma.c:245 mt7601u_complete_tx+0x165/00
[   57.483483] Modules linked in:
[   57.483496] CPU: 1 PID: 32 Comm: kworker/1:1 Not tainted 5.2.0-rc1+ #72
[   57.483498] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.12.0-2.fc30 04/01/2014
[   57.483502] Workqueue: usb_hub_wq hub_event
[   57.483507] RIP: 0010:mt7601u_complete_tx+0x165/0x1e0
[   57.483510] Code: 8b b5 10 04 00 00 8b 8d 14 04 00 00 eb 8b 80 3d b1 cb e1 00 00 75 9e 48 c7 c7 a4 ea 05 82 c6 05 f
[   57.483513] RSP: 0000:ffffc900000a0d28 EFLAGS: 00010092
[   57.483516] RAX: 000000000000000f RBX: ffff88802c0a62c0 RCX: ffffc900000a0c2c
[   57.483518] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff810a8371
[   57.483520] RBP: ffff88803ced6858 R08: 0000000000000000 R09: 0000000000000001
[   57.483540] R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000046
[   57.483542] R13: ffff88802c0a6c88 R14: ffff88803baab540 R15: ffff88803a0cc078
[   57.483548] FS:  0000000000000000(0000) GS:ffff88803eb00000(0000) knlGS:0000000000000000
[   57.483550] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   57.483552] CR2: 000055e7f6780100 CR3: 0000000028c86000 CR4: 00000000000006a0
[   57.483554] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   57.483556] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   57.483559] Call Trace:
[   57.483561]  <IRQ>
[   57.483565]  __usb_hcd_giveback_urb+0x77/0xe0
[   57.483570]  xhci_giveback_urb_in_irq.isra.0+0x8b/0x140
[   57.483574]  handle_cmd_completion+0xf5b/0x12c0
[   57.483577]  xhci_irq+0x1f6/0x1810
[   57.483581]  ? lockdep_hardirqs_on+0x9e/0x180
[   57.483584]  ? _raw_spin_unlock_irq+0x24/0x30
[   57.483588]  __handle_irq_event_percpu+0x3a/0x260
[   57.483592]  handle_irq_event_percpu+0x1c/0x60
[   57.483595]  handle_irq_event+0x2f/0x4c
[   57.483599]  handle_edge_irq+0x7e/0x1a0
[   57.483603]  handle_irq+0x17/0x20
[   57.483607]  do_IRQ+0x54/0x110
[   57.483610]  common_interrupt+0xf/0xf
[   57.483612]  </IRQ>

Acked-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/mediatek/mt7601u/dma.c b/drivers/net/wireless/mediatek/mt7601u/dma.c
index 134f8a5bb5d4d34684e7a7b3ac29925af85a263d..401444f36402caa72061f5de973f314ceca17f6b 100644 (file)
--- a/drivers/net/wireless/mediatek/mt7601u/dma.c
+++ b/drivers/net/wireless/mediatek/mt7601u/dma.c
@@ -241,14 +241,25 @@ static void mt7601u_complete_tx(struct urb *urb)
        struct sk_buff *skb;
        unsigned long flags;
 
-       spin_lock_irqsave(&dev->tx_lock, flags);
+       switch (urb->status) {
+       case -ECONNRESET:
+       case -ESHUTDOWN:
+       case -ENOENT:
+               return;
+       default:
+               dev_err_ratelimited(dev->dev, "tx urb failed: %d\n",
+                                   urb->status);
+               /* fall through */
+       case 0:
+               break;
+       }
 
-       if (mt7601u_urb_has_error(urb))
-               dev_err(dev->dev, "Error: TX urb failed:%d\n", urb->status);
+       spin_lock_irqsave(&dev->tx_lock, flags);
        if (WARN_ONCE(q->e[q->start].urb != urb, "TX urb mismatch"))
                goto out;
 
        skb = q->e[q->start].skb;
+       q->e[q->start].skb = NULL;
        trace_mt_tx_dma_done(dev, skb);
 
        __skb_queue_tail(&dev->tx_skb_done, skb);
@@ -448,10 +459,10 @@ static void mt7601u_free_tx_queue(struct mt7601u_tx_queue *q)
 {
        int i;
 
-       WARN_ON(q->used);
-
        for (i = 0; i < q->entries; i++)  {
                usb_poison_urb(q->e[i].urb);
+               if (q->e[i].skb)
+                       mt7601u_tx_status(q->dev, q->e[i].skb);
                usb_free_urb(q->e[i].urb);
        }
 }

diff --git a/drivers/net/wireless/mediatek/mt7601u/tx.c b/drivers/net/wireless/mediatek/mt7601u/tx.c
index 3600e911a63e85d23ecc15f238c42db66865472d..4d81c45722fbb756dc3c91fa8559772dc8738fda 100644 (file)
--- a/drivers/net/wireless/mediatek/mt7601u/tx.c
+++ b/drivers/net/wireless/mediatek/mt7601u/tx.c
@@ -117,9 +117,9 @@ void mt7601u_tx_status(struct mt7601u_dev *dev, struct sk_buff *skb)
        info->status.rates[0].idx = -1;
        info->flags |= IEEE80211_TX_STAT_ACK;
 
-       spin_lock(&dev->mac_lock);
+       spin_lock_bh(&dev->mac_lock);
        ieee80211_tx_status(dev->hw, skb);
-       spin_unlock(&dev->mac_lock);
+       spin_unlock_bh(&dev->mac_lock);
 }
 
 static int mt7601u_skb_rooms(struct mt7601u_dev *dev, struct sk_buff *skb)