netdev - [PATCH v1 1/1 net-next] 8139cp: Fix one possible deadloop in cp_rx

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Message-Id: <1472089539-11543-1-git-send-email-fgao@ikuai8.com>
Date:   Thu, 25 Aug 2016 09:45:39 +0800
From:   fgao@...ai8.com
To:     dwmw2@...radead.org, davem@...emloft.net, netdev@...r.kernel.org
Cc:     gfree.wind@...il.com, Gao Feng <fgao@...ai8.com>
Subject: [PATCH v1 1/1 net-next] 8139cp: Fix one possible deadloop in cp_rx_poll

From: Gao Feng <fgao@...ai8.com>

When cp_rx_poll does not get enough packet, it will check the rx
interrupt status again. If so, it will jumpt to rx_status_loop again.
But the goto jump resets the rx variable as zero too.

As a result, it causes one possible deadloop. Assume this case,
rx_status_loop only gets the packet count which is less than budget,
and (cpr16(IntrStatus) & cp_rx_intr_mask) condition is always true.
It causes the deadloop happens and system is blocked.

Signed-off-by: Gao Feng <fgao@...ai8.com>
---
 drivers/net/ethernet/realtek/8139cp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/realtek/8139cp.c b/drivers/net/ethernet/realtek/8139cp.c
index deae10d..5297bf7 100644
--- a/drivers/net/ethernet/realtek/8139cp.c
+++ b/drivers/net/ethernet/realtek/8139cp.c
@@ -467,8 +467,8 @@ static int cp_rx_poll(struct napi_struct *napi, int budget)
 	unsigned int rx_tail = cp->rx_tail;
 	int rx;

-rx_status_loop:
 	rx = 0;
+rx_status_loop:
 	cpw16(IntrStatus, cp_rx_intr_mask);

 	while (rx < budget) {
-- 
1.9.1