From: Jiangfeng Xiao xiaojiangfeng@huawei.com
[ Upstream commit 90b3b339364c76baa2436445401ea9ade040c216 ]
When doing stress test, we get the following trace: kernel BUG at lib/dynamic_queue_limits.c:26! Internal error: Oops - BUG: 0 [#1] SMP ARM Modules linked in: hip04_eth CPU: 0 PID: 2003 Comm: tDblStackPcap0 Tainted: G O L 4.4.197 #1 Hardware name: Hisilicon A15 task: c3637668 task.stack: de3bc000 PC is at dql_completed+0x18/0x154 LR is at hip04_tx_reclaim+0x110/0x174 [hip04_eth] pc : [<c041abfc>] lr : [<bf0003a8>] psr: 800f0313 sp : de3bdc2c ip : 00000000 fp : c020fb10 r10: 00000000 r9 : c39b4224 r8 : 00000001 r7 : 00000046 r6 : c39b4000 r5 : 0078f392 r4 : 0078f392 r3 : 00000047 r2 : 00000000 r1 : 00000046 r0 : df5d5c80 Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 32c5387d Table: 1e189b80 DAC: 55555555 Process tDblStackPcap0 (pid: 2003, stack limit = 0xde3bc190) Stack: (0xde3bdc2c to 0xde3be000) [<c041abfc>] (dql_completed) from [<bf0003a8>] (hip04_tx_reclaim+0x110/0x174 [hip04_eth]) [<bf0003a8>] (hip04_tx_reclaim [hip04_eth]) from [<bf0012c0>] (hip04_rx_poll+0x20/0x388 [hip04_eth]) [<bf0012c0>] (hip04_rx_poll [hip04_eth]) from [<c04c8d9c>] (net_rx_action+0x120/0x374) [<c04c8d9c>] (net_rx_action) from [<c021eaf4>] (__do_softirq+0x218/0x318) [<c021eaf4>] (__do_softirq) from [<c021eea0>] (irq_exit+0x88/0xac) [<c021eea0>] (irq_exit) from [<c0240130>] (msa_irq_exit+0x11c/0x1d4) [<c0240130>] (msa_irq_exit) from [<c0267ba8>] (__handle_domain_irq+0x110/0x148) [<c0267ba8>] (__handle_domain_irq) from [<c0201588>] (gic_handle_irq+0xd4/0x118) [<c0201588>] (gic_handle_irq) from [<c0558360>] (__irq_svc+0x40/0x58) Exception stack(0xde3bdde0 to 0xde3bde28) dde0: 00000000 00008001 c3637668 00000000 00000000 a00f0213 dd3627a0 c0af6380 de00: c086d380 a00f0213 c0a22a50 de3bde6c 00000002 de3bde30 c0558138 c055813c de20: 600f0213 ffffffff [<c0558360>] (__irq_svc) from [<c055813c>] (_raw_spin_unlock_irqrestore+0x44/0x54) Kernel panic - not syncing: Fatal exception in interrupt
Pre-modification code: int hip04_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev) { [...] [1] priv->tx_head = TX_NEXT(tx_head); [2] count++; [3] netdev_sent_queue(ndev, skb->len); [...] } An rx interrupt occurs if hip04_mac_start_xmit just executes to the line 2, tx_head has been updated, but corresponding 'skb->len' has not been added to dql_queue.
And then hip04_mac_interrupt->__napi_schedule->hip04_rx_poll->hip04_tx_reclaim
In hip04_tx_reclaim, because tx_head has been updated, bytes_compl will plus an additional "skb-> len" which has not been added to dql_queue. And then trigger the BUG_ON(bytes_compl > num_queued - dql->num_completed).
To solve the problem described above, we put "netdev_sent_queue(ndev, skb->len);" before "priv->tx_head = TX_NEXT(tx_head);"
Fixes: a41ea46a9a12 ("net: hisilicon: new hip04 ethernet driver") Signed-off-by: Jiangfeng Xiao xiaojiangfeng@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/hisilicon/hip04_eth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/hisilicon/hip04_eth.c b/drivers/net/ethernet/hisilicon/hip04_eth.c index 2a7dfac20546..09c51220b5ca 100644 --- a/drivers/net/ethernet/hisilicon/hip04_eth.c +++ b/drivers/net/ethernet/hisilicon/hip04_eth.c @@ -455,9 +455,9 @@ static int hip04_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev) skb_tx_timestamp(skb);
hip04_set_xmit_desc(priv, phys); - priv->tx_head = TX_NEXT(tx_head); count++; netdev_sent_queue(ndev, skb->len); + priv->tx_head = TX_NEXT(tx_head);
stats->tx_bytes += skb->len; stats->tx_packets++;