From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: [BUG][AX25] Fwd: SMP with AX.25 Date: Wed, 6 Feb 2008 09:30:50 +0000 Message-ID: <20080206093050.GF4496@ff.dom.local> References: <20080206074529.GC4496@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ralf Baechle , netdev@vger.kernel.org To: Jann Traschewski Return-path: Received: from ug-out-1314.google.com ([66.249.92.171]:16188 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759706AbYBFJXq (ORCPT ); Wed, 6 Feb 2008 04:23:46 -0500 Received: by ug-out-1314.google.com with SMTP id z38so365708ugc.16 for ; Wed, 06 Feb 2008 01:23:44 -0800 (PST) Content-Disposition: inline In-Reply-To: <20080206074529.GC4496@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Feb 06, 2008 at 07:45:29AM +0000, Jarek Poplawski wrote: ... > From: Jann Traschewski > Subject: SMP with AX.25 > To: jarkao2@gmail.com According to one of OOPSes reported by Jann softirq can break while skb is prepared for netif_rx. The report isn't complete, so the real reason of the later bug could be different, but IMHO this locking in ax_bump is wrong. I attach this patch for testing purpose only. Jarek P. --- drivers/net/hamradio/mkiss.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c index cfcd15a..30c9b3b 100644 --- a/drivers/net/hamradio/mkiss.c +++ b/drivers/net/hamradio/mkiss.c @@ -289,7 +289,6 @@ static void ax_bump(struct mkiss *ax) *ax->rbuff &= ~0x20; } } - spin_unlock_bh(&ax->buflock); count = ax->rcount; @@ -297,17 +296,17 @@ static void ax_bump(struct mkiss *ax) printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n", ax->dev->name); ax->stats.rx_dropped++; + spin_unlock_bh(&ax->buflock); return; } - spin_lock_bh(&ax->buflock); memcpy(skb_put(skb,count), ax->rbuff, count); - spin_unlock_bh(&ax->buflock); skb->protocol = ax25_type_trans(skb, ax->dev); netif_rx(skb); ax->dev->last_rx = jiffies; ax->stats.rx_packets++; ax->stats.rx_bytes += count; + spin_unlock_bh(&ax->buflock); } static void kiss_unesc(struct mkiss *ax, unsigned char s)