On Tue, 27 Nov 2007 14:34:44 -0800
"Kok, Auke" <[EMAIL PROTECTED]> wrote:
> Stephen Hemminger wrote:
> > On Tue, 27 Nov 2007 19:52:24 +0100
> > Robert Olsson <[EMAIL PROTECTED]> wrote:
> >
> >> Hello!
> >>
> >> I've discovered a bug while testing the new multiQ NAPI code. In hi-load
> >> situations when we take down an interface we get a kernel panic. The
> >> oops is below.
> >>
> >> From what I see this happens when driver does napi_disable() and clears
> >> NAPI_STATE_SCHED. In net_rx_action there is a check for work == weight
> >> a sort indirect test but that's now not enough to cover the load
> >> situation.
> >> where we have NAPI_STATE_SCHED cleared by e1000_down in my case and still
> >> full quota. Latest git but I'll guess the is the same in all later kernels.
> >> There might be different solutions... one variant is below:
> >
> > It is considered a driver bug in 2.6.24 to call netif_rx_complete (clear
> > NAPI_STATE_SCHED)
> > and do a full quota. That bug already had to be fixed in other drivers,
> > look like e1000 has same problem.
>
> Stephen,
>
> please enlighten me, can you e.g. show me a commit of other drivers where you
> fixed this up?
>
> Thanks,
>
> Auke
Author: David S. Miller <[EMAIL PROTECTED]> 2007-10-11 18:08:29
Committer: David S. Miller <[EMAIL PROTECTED]> 2007-10-11 18:08:29
Parent: b9f2c0440d806e01968c3ed4def930a43be248ad ([netdrvr] Stop using legacy
hooks ->self_test_count, ->get_stats_count)
Child: 266918303226cceac7eca38ced30f15f277bd89c ([SKY2]: status polling loop
(post merge))
Branches: master, origin
Follows: v2.6.23
Precedes: v2.6.24-rc1
[NET]: Fix NAPI completion handling in some drivers.
In order for the list handling in net_rx_action() to be
correct, drivers must follow certain rules as stated by
this comment in net_rx_action():
/* Drivers must not modify the NAPI state if they
* consume the entire weight. In such cases this code
* still "owns" the NAPI instance and therefore can
* move the instance around on the list at-will.
*/
A few drivers do not do this because they mix the budget checks
with reading hardware state, resulting in crashes like the one
reported by [EMAIL PROTECTED]
BNX2 and TG3 are taken care of here, SKY2 fix is from Stephen
Hemminger.
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
--
Stephen Hemminger <[EMAIL PROTECTED]>
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