[PATCH] b44.c Use dev_kfree_skb_irq() in b44_tx()

From: Xander Hover
Date: Wed Nov 23 2011 - 09:05:07 EST


Reported issues when using dev_kfree_skb() on UP systems and
systems with low numbers of cores. dev_kfree_skb_irq() will
properly save IRQ state before freeing the skb.

Tested on 3.1.1 and 3.2_rc2

Example of reproducible trace of kernel 3.1.1
------------[ cut here ]------------
WARNING: at kernel/softirq.c:159 local_bh_enable+0x32/0x79()
...
Pid: 0, comm: swapper Not tainted 3.1.1-gentoo #1
Call Trace:
[<c1022970>] warn_slowpath_common+0x65/0x7a
[<c102699e>] ? local_bh_enable+0x32/0x79
[<c1022994>] warn_slowpath_null+0xf/0x13
[<c102699e>] local_bh_enable+0x32/0x79
[<c134bfd8>] destroy_conntrack+0x7c/0x9b
[<c134890b>] nf_conntrack_destroy+0x1f/0x26
[<c132e3a6>] skb_release_head_state+0x74/0x83
[<c132e286>] __kfree_skb+0xb/0x6b
[<c132e30a>] consume_skb+0x24/0x26
[<c127c925>] b44_poll+0xaa/0x449
[<c1333ca1>] net_rx_action+0x3f/0xea
[<c1026a44>] __do_softirq+0x5f/0xd5
[<c10269e5>] ? local_bh_enable+0x79/0x79
<IRQ> [<c1026c32>] ? irq_exit+0x34/0x8d
[<c1003628>] ? do_IRQ+0x74/0x87
[<c13f5329>] ? common_interrupt+0x29/0x30
[<c1006e18>] ? default_idle+0x29/0x3e
[<c10015a7>] ? cpu_idle+0x2f/0x5d
[<c13e91c5>] ? rest_init+0x79/0x7b
[<c15c66a9>] ? start_kernel+0x297/0x29c
[<c15c60b0>] ? i386_start_kernel+0xb0/0xb7
---[ end trace 583f33bb1aa207a9 ]---

Signed-off-by: Xander Hover <LKML@xxxxxxxx>
---
drivers/net/ethernet/broadcom/b44.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c
index 4cf835d..3fb66d0 100644
--- a/drivers/net/ethernet/broadcom/b44.c
+++ b/drivers/net/ethernet/broadcom/b44.c
@@ -608,7 +608,7 @@ static void b44_tx(struct b44 *bp)
skb->len,
DMA_TO_DEVICE);
rp->skb = NULL;
- dev_kfree_skb(skb);
+ dev_kfree_skb_irq(skb);
}

bp->tx_cons = cons;
--
1.7.8.rc3

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