This is a note to let you know that I've just added the patch titled
sh_eth: fix napi_{en|dis}able() calls racing against interrupts
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sh_eth-fix-napi_-en-dis-able-calls-racing-against-interrupts.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d3e08db628482ea4580de4fa5a8dba7fe057fddd Mon Sep 17 00:00:00 2001
From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Date: Wed, 4 Sep 2013 02:41:27 +0400
Subject: sh_eth: fix napi_{en|dis}able() calls racing against interrupts
From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
[ Upstream commit d2779e99468fd83ef1493c34f3803fec9aad8345 ]
While implementing NAPI for the driver, I overlooked the race conditions where
interrupt handler might have called napi_schedule_prep() before napi_enable()
was called or after napi_disable() was called. If RX interrupt happens, this
would cause the endless interrupts and messages like:
sh-eth eth0: ignoring interrupt, status 0x00040000, mask 0x01ff009f.
The interrupt wouldn't even be masked by the kernel eventually since the handler
would return IRQ_HANDLED all the time.
As a fix, move napi_enable() call before request_irq() call and napi_disable()
call after free_irq() call.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/renesas/sh_eth.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1857,11 +1857,13 @@ static int sh_eth_open(struct net_device
pm_runtime_get_sync(&mdp->pdev->dev);
+ napi_enable(&mdp->napi);
+
ret = request_irq(ndev->irq, sh_eth_interrupt,
mdp->cd->irq_flags, ndev->name, ndev);
if (ret) {
dev_err(&ndev->dev, "Can not assign IRQ number\n");
- return ret;
+ goto out_napi_off;
}
/* Descriptor set */
@@ -1879,12 +1881,12 @@ static int sh_eth_open(struct net_device
if (ret)
goto out_free_irq;
- napi_enable(&mdp->napi);
-
return ret;
out_free_irq:
free_irq(ndev->irq, ndev);
+out_napi_off:
+ napi_disable(&mdp->napi);
pm_runtime_put_sync(&mdp->pdev->dev);
return ret;
}
@@ -1976,8 +1978,6 @@ static int sh_eth_close(struct net_devic
{
struct sh_eth_private *mdp = netdev_priv(ndev);
- napi_disable(&mdp->napi);
-
netif_stop_queue(ndev);
/* Disable interrupts by clearing the interrupt mask. */
@@ -1995,6 +1995,8 @@ static int sh_eth_close(struct net_devic
free_irq(ndev->irq, ndev);
+ napi_disable(&mdp->napi);
+
/* Free all the skbuffs in the Rx queue. */
sh_eth_ring_free(ndev);
Patches currently in stable-queue which might be from sergei.shtylyov@xxxxxxxxxxxxxxxxxx are
queue-3.11/sh_eth-fix-napi_-en-dis-able-calls-racing-against-interrupts.patch
--
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