2008-10-28 12:06:21

by Will Newton

[permalink] [raw]

Subject: [PATCH] drivers/net/smc911x.c: Fix lockdep warning on xmit.

---

>From 0e3ec7f78e115533e4aca9ac067acbc33eb0a21f Mon Sep 17 00:00:00 2001
From: Will Newton <[email protected]>
Date: Tue, 28 Oct 2008 10:52:36 +0000
Subject: [PATCH] drivers/net/smc911x.c: Fix lockdep warning on xmit.

dev_kfree_skb should not be called with irqs disabled, use dev_kfree_skb_irq
instead. The warning caused looks like this:

======================================================
[ INFO: hard-safe -> hard-unsafe lock order detected ]
2.6.28-rc1 #273
------------------------------------------------------
swapper/0 [HC0[0]:SC1[2]:HE0:SE0] is trying to acquire:
(clock-AF_INET){-..+}, at: [<4015c17c>] _sock_def_write_space+0x28/0xd8

and this task is already holding:
(&lp->lock){++..}, at: [<4013f230>] _smc911x_hard_start_xmit+0x30/0x4b8
which would create a new lock dependency:
(&lp->lock){++..} -> (clock-AF_INET){-..+}

Signed-off-by: Will Newton <[email protected]>
---
drivers/net/smc911x.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/smc911x.c b/drivers/net/smc911x.c
index f59c777..5051554 100644
--- a/drivers/net/smc911x.c
+++ b/drivers/net/smc911x.c
@@ -499,7 +499,7 @@ static void smc911x_hardware_send_pkt(struct
net_device *dev)
#else
SMC_PUSH_DATA(lp, buf, len);
dev->trans_start = jiffies;
- dev_kfree_skb(skb);
+ dev_kfree_skb_irq(skb);
#endif
if (!lp->tx_throttle) {
netif_wake_queue(dev);
--
1.5.5.2

---

Attachments:

(No filename) (1.37 kB)
0001-drivers-net-smc911x.c-Fix-lockdep-warning-on-xmit.patch (1.37 kB)
Download all attachments

2008-11-02 13:46:23

by Jeff Garzik

[permalink] [raw]

Subject: Re: [PATCH] drivers/net/smc911x.c: Fix lockdep warning on xmit.

---

Will Newton wrote:
>>From 0e3ec7f78e115533e4aca9ac067acbc33eb0a21f Mon Sep 17 00:00:00 2001
> From: Will Newton <[email protected]>
> Date: Tue, 28 Oct 2008 10:52:36 +0000
> Subject: [PATCH] drivers/net/smc911x.c: Fix lockdep warning on xmit.
>
> dev_kfree_skb should not be called with irqs disabled, use dev_kfree_skb_irq
> instead. The warning caused looks like this:
>
> ======================================================
> [ INFO: hard-safe -> hard-unsafe lock order detected ]
> 2.6.28-rc1 #273
> ------------------------------------------------------
> swapper/0 [HC0[0]:SC1[2]:HE0:SE0] is trying to acquire:
> (clock-AF_INET){-..+}, at: [<4015c17c>] _sock_def_write_space+0x28/0xd8
>
> and this task is already holding:
> (&lp->lock){++..}, at: [<4013f230>] _smc911x_hard_start_xmit+0x30/0x4b8
> which would create a new lock dependency:
> (&lp->lock){++..} -> (clock-AF_INET){-..+}
>
> Signed-off-by: Will Newton <[email protected]>
> ---
> drivers/net/smc911x.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/smc911x.c b/drivers/net/smc911x.c
> index f59c777..5051554 100644
> --- a/drivers/net/smc911x.c
> +++ b/drivers/net/smc911x.c
> @@ -499,7 +499,7 @@ static void smc911x_hardware_send_pkt(struct
> net_device *dev)
> #else
> SMC_PUSH_DATA(lp, buf, len);
> dev->trans_start = jiffies;
> - dev_kfree_skb(skb);
> + dev_kfree_skb_irq(skb);
> #endif
> if (!lp->tx_throttle) {
> netif_wake_queue(dev);

applied manually, your patch was corrupted