Re: NOHZ: local_softirq_pending 08

From: Johannes Berg
Date: Sun Oct 11 2009 - 06:10:31 EST


On Sun, 2009-10-11 at 17:52 +0800, Dave Young wrote:

> With kernel 2.6.32-rc3-00052-g0eca52a I got following KERN_ERR
> messages just while using firefox:
>
> [ 130.527399] NOHZ: local_softirq_pending 08

> Any idea? or known issue?

Are you using b43 (or wl12x1)? If so, it's a known issue, but the driver
was recently left without an active maintainer in a brouhaha about a bug
fix.

Cf. http://thread.gmane.org/gmane.linux.kernel.wireless.general/39440

Absent proof that mac80211 is safe to run with BHs enabled, the correct
solution is disabling tasklets around the RX function, unlike all the
proposed patches. However, Michael thinks it's such a bad solution that
he has refused to implement it. So far, nobody has bothered to fix the
drivers.

FWIW, I believe the bug to be in b43 and wl12x1, and not as Michael
thinks in the stack.

johannes

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