[PATCH][RFC] preempt_count corruption across H_CEDE call with CONFIG_PREEMPT on pseries
willschm at us.ibm.com
Sat Sep 4 06:10:07 EST 2010
dvhltc at linux.vnet.ibm.com wrote on 09/02/2010 01:04:28 AM:
> Re: [PATCH][RFC] preempt_count corruption across H_CEDE call with
> CONFIG_PREEMPT on pseries
> With this in place, we no longer see the preempt_count dropping below
> zero. However, if I offline/online a CPU about 246 times I hit the
> opposite problem, a preempt_count() overflow. There appears to be a
> missing preempt_enable() somewhere in the offline/online paths.
This (preempt_count overflow) also occurred in mainline (with
CONFIG_PREEMPT=y) in 2.6.35, but not in 2.6.36-rc3. A
bisect seems to indicate it was fixed with
a7c2bb8279d20d853e43c34584eaf2b039de8026 "powerpc: Re-enable preemption
Which may look familiar. :-)
It looks like this patch went to mainline (likely via the powerpc tree),
have not gotten back into the -rt branch.
> Darren Hart
> IBM Linux Technology Center
> Real-Time Linux Team
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Linuxppc-dev