Re: [RFC] sunrpc: Fix race between work-queue and rpc_killall_tasks.

[Ben Greear]

On 07/12/2011 10:30 AM, Ben Greear wrote:
> On 07/12/2011 10:25 AM, Myklebust, Trond wrote:
> > > -----Original Message-----
> > > From: Ben Greear [mailto:greearb@xxxxxxxxxxxxxxx]
> > > Sent: Tuesday, July 12, 2011 1:15 PM
> > > To: Myklebust, Trond
> > > Cc: linux-nfs@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> > > Subject: Re: [RFC] sunrpc: Fix race between work-queue and
> > > rpc_killall_tasks.

> > > I added lots of locking around the calldata, work-queue logic, and
> > > such, and
> > > still the problem persists w/out hitting any of the debug warnings or
> > > poisoned
> > > values I put in. It almost seems like tk_calldata is just assigned to
> > > two
> > > different tasks.
> > >
> > > While poking through the code, I noticed that 'map' is static in
> > > rpcb_getport_async.
> > >
> > > That would seem to cause problems if two threads called this method at
> > > the same time, possibly causing tk_calldata to be assigned to two
> > > different
> > > tasks???
> > >
> > > Any idea why it is static?
> >
> > Doh! That is clearly a typo dating all the way back to when Chuck
> > wrote that function.
> >
> > Yes, that would definitely explain your problem.
>
> Ok, patch sent. I assume someone will propagate this to stable
> as desired?
>
> And assuming this fixes it, can I get some brownie points towards
> review of the ip-addr binding patches? :)

Just to close this issue:  We ran a clean 24+ hour test mounting and
unmounting 200 mounts every 30 seconds, and it ran with zero problems.

This was with 2.6.38.8+ with this fix applied.

3.0-rc7+ is still flaky in various other ways, but I see no more
NFS problems at least.

So, that was the problem I was hitting, and it appears to be the
last problem in this area.

Thanks,
Ben

--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com

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