Fixes for rockchip EMAC

Fixes for rockchip EMAC

[Alexander Kochetkov]

Hello!

Here is a set of 3 patches what fix koops, memory leak and
rockchip EMAC hang. Tested on radxarock lite.

[PATCH 1/3] net: arc_emac: fix koops caused by sk_buff free
[PATCH 2/3] net: arc_emac: reset txbd_curr and txbd_dirty pointers
[PATCH 3/3] net: arc_emac: fix sk_buff leak

[PATCH 1/3] net: arc_emac: fix koops caused by sk_buff free

[Alexander Kochetkov]

There is a race between arc_emac_tx() and arc_emac_tx_clean().
sk_buff got freed by arc_emac_tx_clean() while arc_emac_tx()
submitting sk_buff.

In order to free sk_buff arc_emac_tx_clean() checks:
    if ((info & FOR_EMAC) || !txbd->data)
        break;
    ...
    dev_kfree_skb_irq(skb);

If condition false, arc_emac_tx_clean() free sk_buff.

In order to submit txbd, arc_emac_tx() do:
    priv->tx_buff[*txbd_curr].skb = skb;
    ...
    priv->txbd[*txbd_curr].data = cpu_to_le32(addr);
    ...
    ...  <== arc_emac_tx_clean() check condition here
    ...  <== (info & FOR_EMAC) is false
    ...  <== !txbd->data is false
    ...
    *info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);

In order to reproduce the situation,
run device:
    # iperf -s
run on host:
    # iperf -t 600 -c <device-ip-addr>

[   28.396284] ------------[ cut here ]------------
[   28.400912] kernel BUG at .../net/core/skbuff.c:1355!
[   28.414019] Internal error: Oops - BUG: 0 [#1] SMP ARM
[   28.419150] Modules linked in:
[   28.422219] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G    B           4.4.0+ #120
[   28.429516] Hardware name: Rockchip (Device Tree)
[   28.434216] task: c0665070 ti: c0660000 task.ti: c0660000
[   28.439622] PC is at skb_put+0x10/0x54
[   28.443381] LR is at arc_emac_poll+0x260/0x474
[   28.447821] pc : [<c03af580>]    lr : [<c028fec4>]    psr: a0070113
[   28.447821] sp : c0661e58  ip : eea68502  fp : ef377000
[   28.459280] r10: 0000012c  r9 : f08b2000  r8 : eeb57100
[   28.464498] r7 : 00000000  r6 : ef376594  r5 : 00000077  r4 : ef376000
[   28.471015] r3 : 0030488b  r2 : ef13e880  r1 : 000005ee  r0 : eeb57100
[   28.477534] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[   28.484658] Control: 10c5387d  Table: 8eaf004a  DAC: 00000051
[   28.490396] Process swapper/0 (pid: 0, stack limit = 0xc0660210)
[   28.496393] Stack: (0xc0661e58 to 0xc0662000)
[   28.500745] 1e40:                                                       00000002 00000000
[   28.508913] 1e60: 00000000 ef376520 00000028 f08b23b8 00000000 ef376520 ef7b6900 c028fc64
[   28.517082] 1e80: 2f158000 c0661ea8 c0661eb0 0000012c c065e900 c03bdeac ffff95e9 c0662100
[   28.525250] 1ea0: c0663924 00000028 c0661ea8 c0661ea8 c0661eb0 c0661eb0 0000001e c0660000
[   28.533417] 1ec0: 40000003 00000008 c0695a00 0000000a c066208c 00000100 c0661ee0 c0027410
[   28.541584] 1ee0: ef0fb700 2f158000 00200000 ffff95e8 00000004 c0662100 c0662080 00000003
[   28.549751] 1f00: 00000000 00000000 00000000 c065b45c 0000001e ef005000 c0647a30 00000000
[   28.557919] 1f20: 00000000 c0027798 00000000 c005cf40 f0802100 c0662ffc c0661f60 f0803100
[   28.566088] 1f40: c0661fb8 c00093bc c000ffb4 60070013 ffffffff c0661f94 c0661fb8 c00137d4
[   28.574267] 1f60: 00000001 00000000 00000000 c001ffa0 00000000 c0660000 00000000 c065a364
[   28.582441] 1f80: c0661fb8 c0647a30 00000000 00000000 00000000 c0661fb0 c000ffb0 c000ffb4
[   28.590608] 1fa0: 60070013 ffffffff 00000051 00000000 00000000 c005496c c0662400 c061bc40
[   28.598776] 1fc0: ffffffff ffffffff 00000000 c061b680 00000000 c0647a30 00000000 c0695294
[   28.606943] 1fe0: c0662488 c0647a2c c066619c 6000406a 413fc090 6000807c 00000000 00000000
[   28.615127] [<c03af580>] (skb_put) from [<ef376520>] (0xef376520)
[   28.621218] Code: e5902054 e590c090 e3520000 0a000000 (e7f001f2)
[   28.627307] ---[ end trace 4824734e2243fdb6 ]---

[   34.377068] Internal error: Oops: 17 [#1] SMP ARM
[   34.382854] Modules linked in:
[   34.385947] CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.4.0+ #120
[   34.392219] Hardware name: Rockchip (Device Tree)
[   34.396937] task: ef02d040 ti: ef05c000 task.ti: ef05c000
[   34.402376] PC is at __dev_kfree_skb_irq+0x4/0x80
[   34.407121] LR is at arc_emac_poll+0x130/0x474
[   34.411583] pc : [<c03bb640>]    lr : [<c028fd94>]    psr: 60030013
[   34.411583] sp : ef05de68  ip : 0008e83c  fp : ef377000
[   34.423062] r10: c001bec4  r9 : 00000000  r8 : f08b24c8
[   34.428296] r7 : f08b2400  r6 : 00000075  r5 : 00000019  r4 : ef376000
[   34.434827] r3 : 00060000  r2 : 00000042  r1 : 00000001  r0 : 00000000
[   34.441365] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[   34.448507] Control: 10c5387d  Table: 8f25c04a  DAC: 00000051
[   34.454262] Process ksoftirqd/0 (pid: 3, stack limit = 0xef05c210)
[   34.460449] Stack: (0xef05de68 to 0xef05e000)
[   34.464827] de60:                   ef376000 c028fd94 00000000 c0669480 c0669480 ef376520
[   34.473022] de80: 00000028 00000001 00002ae4 ef376520 ef7b6900 c028fc64 2f158000 ef05dec0
[   34.481215] dea0: ef05dec8 0000012c c065e900 c03bdeac ffff983f c0662100 c0663924 00000028
[   34.489409] dec0: ef05dec0 ef05dec0 ef05dec8 ef05dec8 ef7b6000 ef05c000 40000003 00000008
[   34.497600] dee0: c0695a00 0000000a c066208c 00000100 ef05def8 c0027410 ef7b6000 40000000
[   34.505795] df00: 04208040 ffff983e 00000004 c0662100 c0662080 00000003 ef05c000 ef027340
[   34.513985] df20: ef05c000 c0666c2c 00000000 00000001 00000002 00000000 00000000 c0027568
[   34.522176] df40: ef027340 c003ef48 ef027300 00000000 ef027340 c003edd4 00000000 00000000
[   34.530367] df60: 00000000 c003c37c ffffff7f 00000001 00000000 ef027340 00000000 00030003
[   34.538559] df80: ef05df80 ef05df80 00000000 00000000 ef05df90 ef05df90 ef05dfac ef027300
[   34.546750] dfa0: c003c2a4 00000000 00000000 c000f578 00000000 00000000 00000000 00000000
[   34.554939] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[   34.563129] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff dfff7fff
[   34.571360] [<c03bb640>] (__dev_kfree_skb_irq) from [<c028fd94>] (arc_emac_poll+0x130/0x474)
[   34.579840] [<c028fd94>] (arc_emac_poll) from [<c03bdeac>] (net_rx_action+0xdc/0x28c)
[   34.587712] [<c03bdeac>] (net_rx_action) from [<c0027410>] (__do_softirq+0xcc/0x1f8)
[   34.595482] [<c0027410>] (__do_softirq) from [<c0027568>] (run_ksoftirqd+0x2c/0x50)
[   34.603168] [<c0027568>] (run_ksoftirqd) from [<c003ef48>] (smpboot_thread_fn+0x174/0x18c)
[   34.611466] [<c003ef48>] (smpboot_thread_fn) from [<c003c37c>] (kthread+0xd8/0xec)
[   34.619075] [<c003c37c>] (kthread) from [<c000f578>] (ret_from_fork+0x14/0x3c)
[   34.626317] Code: e8bd8010 e3a00000 e12fff1e e92d4010 (e59030a4)
[   34.632572] ---[ end trace cca5a3d86a82249a ]---

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>

---
CC: stable@vger.kernel.org # 3.18.x-
---
 drivers/net/ethernet/arc/emac_main.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
index abe1eab..63a63e3 100644
--- a/drivers/net/ethernet/arc/emac_main.c
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -163,7 +163,7 @@ static void arc_emac_tx_clean(struct net_device *ndev)
 		struct sk_buff *skb = tx_buff->skb;
 		unsigned int info = le32_to_cpu(txbd->info);
 
-		if ((info & FOR_EMAC) || !txbd->data)
+		if ((info & FOR_EMAC) || !txbd->data || !skb)
 			break;
 
 		if (unlikely(info & (DROP | DEFR | LTCL | UFLO))) {
@@ -191,6 +191,7 @@ static void arc_emac_tx_clean(struct net_device *ndev)
 
 		txbd->data = 0;
 		txbd->info = 0;
+		tx_buff->skb = NULL;
 
 		*txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
 	}
@@ -610,7 +611,6 @@ static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
 	dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], addr, addr);
 	dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);
 
-	priv->tx_buff[*txbd_curr].skb = skb;
 	priv->txbd[*txbd_curr].data = cpu_to_le32(addr);
 
 	/* Make sure pointer to data buffer is set */
@@ -620,6 +620,11 @@ static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
 
 	*info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);
 
+	/* Make sure info word is set */
+	wmb();
+
+	priv->tx_buff[*txbd_curr].skb = skb;
+
 	/* Increment index to point to the next BD */
 	*txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;
 
-- 
1.7.9.5

[PATCH 2/3] net: arc_emac: reset txbd_curr and txbd_dirty pointers to zero

[Alexander Kochetkov]

EMAC reset internal tx ring pointer to zero at statup.
txbd_curr and txbd_dirty can be different from zero.
That cause ethernet transfer hang (no packets transmitted).

In order to reproduce, run on device:
    ifconfig eth0 down
    ifconfig eth0 up

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>

---
CC: stable@vger.kernel.org # 3.18.x-
---
 drivers/net/ethernet/arc/emac_main.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
index 63a63e3..4f6e5be 100644
--- a/drivers/net/ethernet/arc/emac_main.c
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -447,6 +447,9 @@ static int arc_emac_open(struct net_device *ndev)
 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
 	}
 
+	priv->txbd_curr = 0;
+	priv->txbd_dirty = 0;
+
 	/* Clean Tx BD's */
 	memset(priv->txbd, 0, TX_RING_SZ);
 
-- 
1.7.9.5

[PATCH 3/3] net: arc_emac: fix sk_buff leak

[Alexander Kochetkov]

EMAC could be disabled, while there is some sb_buff
in use. That buffers got lost for linux.

In order to reproduce run on device during active ethernet work:
    ifconfig eth0 down

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>

---
CC: stable@vger.kernel.org # 3.18.x-
---
 drivers/net/ethernet/arc/emac_main.c |   62 ++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
index 4f6e5be..6446af1 100644
--- a/drivers/net/ethernet/arc/emac_main.c
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -518,6 +518,64 @@ static void arc_emac_set_rx_mode(struct net_device *ndev)
 }
 
 /**
+ * arc_free_tx_queue - free skb from tx queue
+ * @ndev:	Pointer to the network device.
+ *
+ * This function must be called while EMAC disable
+ */
+static void arc_free_tx_queue(struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	unsigned int i;
+
+	for (i = 0; i < TX_BD_NUM; i++) {
+		struct arc_emac_bd *txbd = &priv->txbd[i];
+		struct buffer_state *tx_buff = &priv->tx_buff[i];
+
+		if (tx_buff->skb) {
+			dma_unmap_single(&ndev->dev, dma_unmap_addr(tx_buff, addr),
+					 dma_unmap_len(tx_buff, len), DMA_TO_DEVICE);
+
+			/* return the sk_buff to system */
+			dev_kfree_skb_irq(tx_buff->skb);
+		}
+
+		txbd->info = 0;
+		txbd->data = 0;
+		tx_buff->skb = NULL;
+	}
+}
+
+/**
+ * arc_free_rx_queue - free skb from rx queue
+ * @ndev:	Pointer to the network device.
+ *
+ * This function must be called while EMAC disable
+ */
+static void arc_free_rx_queue(struct net_device *ndev)
+{
+	struct arc_emac_priv *priv = netdev_priv(ndev);
+	unsigned int i;
+
+	for (i = 0; i < RX_BD_NUM; i++) {
+		struct arc_emac_bd *rxbd = &priv->rxbd[i];
+		struct buffer_state *rx_buff = &priv->rx_buff[i];
+
+		if (rx_buff->skb) {
+			dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),
+					dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);
+
+			/* return the sk_buff to system */
+			dev_kfree_skb_irq(rx_buff->skb);
+		}
+
+		rxbd->info = 0;
+		rxbd->data = 0;
+		rx_buff->skb = NULL;
+	}
+}
+
+/**
  * arc_emac_stop - Close the network device.
  * @ndev:	Pointer to the network device.
  *
@@ -538,6 +596,10 @@ static int arc_emac_stop(struct net_device *ndev)
 	/* Disable EMAC */
 	arc_reg_clr(priv, R_CTRL, EN_MASK);
 
+	/* Return the sk_buff to system */
+	arc_free_tx_queue(ndev);
+	arc_free_rx_queue(ndev);
+
 	return 0;
 }
 
-- 
1.7.9.5

Re: Fixes for rockchip EMAC

[David Miller]

From: Alexander Kochetkov <al.kochet@gmail.com>
Date: Tue,  9 Feb 2016 18:20:37 +0300

> Here is a set of 3 patches what fix koops, memory leak and
> rockchip EMAC hang. Tested on radxarock lite.

Series applied, thanks.