[PATCH v2 0/2] mt7601u: do not schedule {rx,tx}_tasklet when the device has been disconnected

[PATCH v2 0/2] mt7601u: do not schedule {rx,tx}_tasklet when the device has been disconnected

[Lorenzo Bianconi]

Do not schedule {tx,rx}_tasklet when the usb dongle is disconnected in order to fix
{TX,RX} urb mismatch warning
Fix possible memory leak when the device is disconnected while passing traffic.

Changes since v1:
- move tasklet_kill back in mt7601u_dma_cleanup
- add more comments and improve commit messages

Lorenzo Bianconi (2):
  mt7601u: do not schedule rx_tasklet when the device has been
    disconnected
  mt7601u: fix possible memory leak when the device is disconnected

 drivers/net/wireless/mediatek/mt7601u/dma.c | 54 +++++++++++++--------
 drivers/net/wireless/mediatek/mt7601u/tx.c  |  4 +-
 2 files changed, 36 insertions(+), 22 deletions(-)

-- 
2.21.0

[PATCH v2 1/2] mt7601u: do not schedule rx_tasklet when the device has been disconnected

[Lorenzo Bianconi]

Do not schedule rx_tasklet when the usb dongle is disconnected.
Moreover do not grub rx_lock in mt7601u_kill_rx since usb_poison_urb
can run concurrently with urb completion and we can unlink urbs from rx
ring in any order.
This patch fixes the common kernel warning reported when
the device is removed.

[   24.921354] usb 3-14: USB disconnect, device number 7
[   24.921593] ------------[ cut here ]------------
[   24.921594] RX urb mismatch
[   24.921675] WARNING: CPU: 4 PID: 163 at drivers/net/wireless/mediatek/mt7601u/dma.c:200 mt7601u_complete_rx+0xcb/0xd0 [mt7601u]
[   24.921769] CPU: 4 PID: 163 Comm: kworker/4:2 Tainted: G           OE     4.19.31-041931-generic #201903231635
[   24.921770] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./Z97 Extreme4, BIOS P1.30 05/23/2014
[   24.921782] Workqueue: usb_hub_wq hub_event
[   24.921797] RIP: 0010:mt7601u_complete_rx+0xcb/0xd0 [mt7601u]
[   24.921800] RSP: 0018:ffff9bd9cfd03d08 EFLAGS: 00010086
[   24.921802] RAX: 0000000000000000 RBX: ffff9bd9bf043540 RCX: 0000000000000006
[   24.921803] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff9bd9cfd16420
[   24.921804] RBP: ffff9bd9cfd03d28 R08: 0000000000000002 R09: 00000000000003a8
[   24.921805] R10: 0000002f485fca34 R11: 0000000000000000 R12: ffff9bd9bf043c1c
[   24.921806] R13: ffff9bd9c62fa3c0 R14: 0000000000000082 R15: 0000000000000000
[   24.921807] FS:  0000000000000000(0000) GS:ffff9bd9cfd00000(0000) knlGS:0000000000000000
[   24.921808] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   24.921808] CR2: 00007fb2648b0000 CR3: 0000000142c0a004 CR4: 00000000001606e0
[   24.921809] Call Trace:
[   24.921812]  <IRQ>
[   24.921819]  __usb_hcd_giveback_urb+0x8b/0x140
[   24.921821]  usb_hcd_giveback_urb+0xca/0xe0
[   24.921828]  xhci_giveback_urb_in_irq.isra.42+0x82/0xf0
[   24.921834]  handle_cmd_completion+0xe02/0x10d0
[   24.921837]  xhci_irq+0x274/0x4a0
[   24.921838]  xhci_msi_irq+0x11/0x20
[   24.921851]  __handle_irq_event_percpu+0x44/0x190
[   24.921856]  handle_irq_event_percpu+0x32/0x80
[   24.921861]  handle_irq_event+0x3b/0x5a
[   24.921867]  handle_edge_irq+0x80/0x190
[   24.921874]  handle_irq+0x20/0x30
[   24.921889]  do_IRQ+0x4e/0xe0
[   24.921891]  common_interrupt+0xf/0xf
[   24.921892]  </IRQ>
[   24.921900] RIP: 0010:usb_hcd_flush_endpoint+0x78/0x180
[   24.921354] usb 3-14: USB disconnect, device number 7

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/wireless/mediatek/mt7601u/dma.c | 33 +++++++++++----------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt7601u/dma.c b/drivers/net/wireless/mediatek/mt7601u/dma.c
index f7edeffb2b19..134f8a5bb5d4 100644
--- a/drivers/net/wireless/mediatek/mt7601u/dma.c
+++ b/drivers/net/wireless/mediatek/mt7601u/dma.c
@@ -193,10 +193,23 @@ static void mt7601u_complete_rx(struct urb *urb)
 	struct mt7601u_rx_queue *q = &dev->rx_q;
 	unsigned long flags;
 
-	spin_lock_irqsave(&dev->rx_lock, flags);
+	/* do no schedule rx tasklet if urb has been unlinked
+	 * or the device has been removed
+	 */
+	switch (urb->status) {
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+	case -ENOENT:
+		return;
+	default:
+		dev_err_ratelimited(dev->dev, "rx urb failed: %d\n",
+				    urb->status);
+		/* fall through */
+	case 0:
+		break;
+	}
 
-	if (mt7601u_urb_has_error(urb))
-		dev_err(dev->dev, "Error: RX urb failed:%d\n", urb->status);
+	spin_lock_irqsave(&dev->rx_lock, flags);
 	if (WARN_ONCE(q->e[q->end].urb != urb, "RX urb mismatch"))
 		goto out;
 
@@ -363,19 +376,9 @@ int mt7601u_dma_enqueue_tx(struct mt7601u_dev *dev, struct sk_buff *skb,
 static void mt7601u_kill_rx(struct mt7601u_dev *dev)
 {
 	int i;
-	unsigned long flags;
 
-	spin_lock_irqsave(&dev->rx_lock, flags);
-
-	for (i = 0; i < dev->rx_q.entries; i++) {
-		int next = dev->rx_q.end;
-
-		spin_unlock_irqrestore(&dev->rx_lock, flags);
-		usb_poison_urb(dev->rx_q.e[next].urb);
-		spin_lock_irqsave(&dev->rx_lock, flags);
-	}
-
-	spin_unlock_irqrestore(&dev->rx_lock, flags);
+	for (i = 0; i < dev->rx_q.entries; i++)
+		usb_poison_urb(dev->rx_q.e[i].urb);
 }
 
 static int mt7601u_submit_rx_buf(struct mt7601u_dev *dev,
-- 
2.21.0

[PATCH v2 2/2] mt7601u: fix possible memory leak when the device is disconnected

[Lorenzo Bianconi]

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>
---
 drivers/net/wireless/mediatek/mt7601u/dma.c | 21 ++++++++++++++++-----
 drivers/net/wireless/mediatek/mt7601u/tx.c  |  4 ++--
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt7601u/dma.c b/drivers/net/wireless/mediatek/mt7601u/dma.c
index 134f8a5bb5d4..401444f36402 100644
--- 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 3600e911a63e..4d81c45722fb 100644
--- 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)
-- 
2.21.0

Re: [PATCH v2 0/2] mt7601u: do not schedule {rx,tx}_tasklet when the device has been disconnected

[Jakub Kicinski]

On Fri,  7 Jun 2019 13:48:08 +0200, Lorenzo Bianconi wrote:
> Do not schedule {tx,rx}_tasklet when the usb dongle is disconnected in order to fix
> {TX,RX} urb mismatch warning
> Fix possible memory leak when the device is disconnected while passing traffic.

Acked-by: Jakub Kicinski <kubakici@wp.pl>

Thanks Lorenzo!

Re: [PATCH v2 1/2] mt7601u: do not schedule rx_tasklet when the device has been disconnected

[Kalle Valo]

Lorenzo Bianconi <lorenzo@kernel.org> wrote:

> Do not schedule rx_tasklet when the usb dongle is disconnected.
> Moreover do not grub rx_lock in mt7601u_kill_rx since usb_poison_urb
> can run concurrently with urb completion and we can unlink urbs from rx
> ring in any order.
> This patch fixes the common kernel warning reported when
> the device is removed.
> 
> [   24.921354] usb 3-14: USB disconnect, device number 7
> [   24.921593] ------------[ cut here ]------------
> [   24.921594] RX urb mismatch
> [   24.921675] WARNING: CPU: 4 PID: 163 at drivers/net/wireless/mediatek/mt7601u/dma.c:200 mt7601u_complete_rx+0xcb/0xd0 [mt7601u]
> [   24.921769] CPU: 4 PID: 163 Comm: kworker/4:2 Tainted: G           OE     4.19.31-041931-generic #201903231635
> [   24.921770] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./Z97 Extreme4, BIOS P1.30 05/23/2014
> [   24.921782] Workqueue: usb_hub_wq hub_event
> [   24.921797] RIP: 0010:mt7601u_complete_rx+0xcb/0xd0 [mt7601u]
> [   24.921800] RSP: 0018:ffff9bd9cfd03d08 EFLAGS: 00010086
> [   24.921802] RAX: 0000000000000000 RBX: ffff9bd9bf043540 RCX: 0000000000000006
> [   24.921803] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff9bd9cfd16420
> [   24.921804] RBP: ffff9bd9cfd03d28 R08: 0000000000000002 R09: 00000000000003a8
> [   24.921805] R10: 0000002f485fca34 R11: 0000000000000000 R12: ffff9bd9bf043c1c
> [   24.921806] R13: ffff9bd9c62fa3c0 R14: 0000000000000082 R15: 0000000000000000
> [   24.921807] FS:  0000000000000000(0000) GS:ffff9bd9cfd00000(0000) knlGS:0000000000000000
> [   24.921808] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   24.921808] CR2: 00007fb2648b0000 CR3: 0000000142c0a004 CR4: 00000000001606e0
> [   24.921809] Call Trace:
> [   24.921812]  <IRQ>
> [   24.921819]  __usb_hcd_giveback_urb+0x8b/0x140
> [   24.921821]  usb_hcd_giveback_urb+0xca/0xe0
> [   24.921828]  xhci_giveback_urb_in_irq.isra.42+0x82/0xf0
> [   24.921834]  handle_cmd_completion+0xe02/0x10d0
> [   24.921837]  xhci_irq+0x274/0x4a0
> [   24.921838]  xhci_msi_irq+0x11/0x20
> [   24.921851]  __handle_irq_event_percpu+0x44/0x190
> [   24.921856]  handle_irq_event_percpu+0x32/0x80
> [   24.921861]  handle_irq_event+0x3b/0x5a
> [   24.921867]  handle_edge_irq+0x80/0x190
> [   24.921874]  handle_irq+0x20/0x30
> [   24.921889]  do_IRQ+0x4e/0xe0
> [   24.921891]  common_interrupt+0xf/0xf
> [   24.921892]  </IRQ>
> [   24.921900] RIP: 0010:usb_hcd_flush_endpoint+0x78/0x180
> [   24.921354] usb 3-14: USB disconnect, device number 7
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

2 patches applied to wireless-drivers-next.git, thanks.

4079e8ccabc3 mt7601u: do not schedule rx_tasklet when the device has been disconnected
23377c200b2e mt7601u: fix possible memory leak when the device is disconnected

-- 
https://patchwork.kernel.org/patch/10981545/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches