From: Jarek Poplawski on
On Thu, Jan 07, 2010 at 10:03:51AM -0500, Michael Breuer wrote:
> On 1/7/2010 3:21 AM, Jarek Poplawski wrote:
> >On Thu, Jan 07, 2010 at 02:55:20AM -0500, Michael Breuer wrote:
> >>Unless I misread the code, I think that in some cases e skb is actually
> >>freed if the cfq (among others perhaps) scheduler returns an error on
> >>enqueue (flow control perhaps). Thus with alternative 1, it is possible
> >>that the skb is acted upon after being freed - this would be consistent
> >>with the DMAR errors I saw.
> >I can't see your point: could you give some scenario?
> >
> >Jarek P.
> With NET_CLS_ACT set, net_dev_enqueue can return an error after
> freeing the skb. Alternative 1 disregards the error and assumes the
> skb is still valid. The original code and alternative 2 exit the
> loop assuming the skb has been freed.

Not exactly: alternative 1 disregards the error, and tries to send
next skbs if the message was longer. After consuming all the message
it returns without err code (at least wrt. dev_queue_xmit). This is
quite often practice to skip dev_queue_xmit() return (try to grep in
net\). It should never touch any part of an earlier sent skb.

Jarek P.
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From: Jarek Poplawski on
On Thu, Jan 07, 2010 at 10:05:37AM -0500, Michael Breuer wrote:
> Bad news - crashed about an hour after I wrote this email - under
> load - same crash as before. Network watchdog... lots of attempts to
> reset the adapter... then hw watchdog rebooted the system.

It's a pity. Anyway, I'd be still interested in CONFIG_PACKET_MMAP off
if you find time.

Jarek P.
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From: Jarek Poplawski on
On Thu, Jan 07, 2010 at 06:56:10PM +0100, Jarek Poplawski wrote:
> [...] (try to grep in net\). [...]

Did I say "net\"?!

Extremely sorry! ;-)
Jarek P.
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From: Michael Breuer on
On 1/7/2010 1:01 PM, Jarek Poplawski wrote:
> On Thu, Jan 07, 2010 at 10:05:37AM -0500, Michael Breuer wrote:
>
>> Bad news - crashed about an hour after I wrote this email - under
>> load - same crash as before. Network watchdog... lots of attempts to
>> reset the adapter... then hw watchdog rebooted the system.
>>
> It's a pity. Anyway, I'd be still interested in CONFIG_PACKET_MMAP off
> if you find time.
>
> Jarek P.
>
Ok - any particular patch set to try with? I'm going to start with a
clean tree using the latest 2.6.32 from git (tried 2.6.33-rc3, but can't
get a usable console... will look at that later.)
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From: Jarek Poplawski on
On Thu, Jan 07, 2010 at 01:19:41PM -0500, Michael Breuer wrote:
> On 1/7/2010 1:01 PM, Jarek Poplawski wrote:
> >On Thu, Jan 07, 2010 at 10:05:37AM -0500, Michael Breuer wrote:
> >>Bad news - crashed about an hour after I wrote this email - under
> >>load - same crash as before. Network watchdog... lots of attempts to
> >>reset the adapter... then hw watchdog rebooted the system.
> >It's a pity. Anyway, I'd be still interested in CONFIG_PACKET_MMAP off
> >if you find time.
> >
> >Jarek P.
> Ok - any particular patch set to try with? I'm going to start with a
> clean tree using the latest 2.6.32 from git (tried 2.6.33-rc3, but
> can't get a usable console... will look at that later.)

My "Berck E. Nash" and Stephen's "pskb_may_pull" sky2 patches. (BTW,
could you remind if it worked any better with 2.6.31 or earlier?)

Jarek P.
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