Messages in this thread Patch in this message |  | | | Date | Tue, 24 Mar 2009 15:39:42 +0100 | | From | Ingo Molnar <> | | Subject | Re: Revert "gro: Fix legacy path napi_complete crash", (was: Re: Linux 2.6.29) |
* Robert Schwebel <r.schwebel@pengutronix.de> wrote:
> On Tue, Mar 24, 2009 at 02:02:02PM +0100, Ingo Molnar wrote: > > If the box hung within 15 minutes, the kernel was deemed bad. Using > > that method i arrived to this upstream networking fix which was > > merged yesterday: > > > > | 303c6a0251852ecbdc5c15e466dcaff5971f7517 is first bad commit > > | commit 303c6a0251852ecbdc5c15e466dcaff5971f7517 > > | Author: Herbert Xu <herbert@gondor.apana.org.au> > > | Date: Tue Mar 17 13:11:29 2009 -0700 > > | > > | gro: Fix legacy path napi_complete crash > > This commit breaks nfsroot booting on i.MX27 and other ARM boxes > with different network cards here in a reproducable way.
Can you confirm that Herbert's fix (see it below) solves the problem?
Ingo
---------------> From b8b66ac07cab1b45aac93e4f406833a1e0d7677e Mon Sep 17 00:00:00 2001 From: Herbert Xu <herbert@gondor.apana.org.au> Date: Tue, 24 Mar 2009 21:35:42 +0800 Subject: [PATCH] net: Fix netpoll lockup in legacy receive path When I fixed the GRO crash in the legacy receive path I used napi_complete to replace __napi_complete. Unfortunately they're not the same when NETPOLL is enabled, which may result in us not calling __napi_complete at all.
While this is fishy in itself, let's make the obvious fix right now of reverting to the previous state where we always called __napi_complete.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Frank Blaschka <blaschka@linux.vnet.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090324133542.GA29046@gondor.apana.org.au> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- net/core/dev.c | 16 +++++++++------- 1 files changed, 9 insertions(+), 7 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index e3fe5c7..523f53e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2580,24 +2580,26 @@ static int process_backlog(struct napi_struct *napi, int quota) int work = 0; struct softnet_data *queue = &__get_cpu_var(softnet_data); unsigned long start_time = jiffies; + struct sk_buff *skb; napi->weight = weight_p; do { - struct sk_buff *skb; - local_irq_disable(); skb = __skb_dequeue(&queue->input_pkt_queue); - if (!skb) { - local_irq_enable(); - napi_complete(napi); - goto out; - } local_irq_enable(); + if (!skb) + break; napi_gro_receive(napi, skb); } while (++work < quota && jiffies == start_time); napi_gro_flush(napi); + if (skb) + goto out; + + local_irq_disable(); + __napi_complete(napi); + local_irq_enable(); out: return work;
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