On Fri, Nov 20, 2009 at 05:24:43PM -0500, Chuck Lever wrote:
> On Nov 20, 2009, at 5:05 PM, J. Bruce Fields wrote:
>> On Fri, Nov 20, 2009 at 04:50:34PM -0500, Chuck Lever wrote:
>>> On Nov 20, 2009, at 3:18 PM, Trond Myklebust wrote:
>>>> On Thu, 2009-11-05 at 13:23 -0500, Chuck Lever wrote:
>>>>> + static DEFINE_SPINLOCK(rpcb_create_local_lock);
>>>>> + struct rpc_clnt *clnt, *clnt4;
>>>>> + int result = 0;
>>>>> +
>>>>> + spin_lock(&rpcb_create_local_lock);
>>>>> + if (rpcb_local_clnt)
>>>>> + goto out;
>>>>> +
>>>>> + clnt = rpc_create(&args);
>>>>> + if (IS_ERR(clnt)) {
>>>>> + result = -PTR_ERR(clnt);
>>>>> + goto out;
>>>>> + }
>>>>>
>>>>> - return rpc_create(&args);
>>>>> + clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
>>>>> + if (IS_ERR(clnt4)) {
>>>>> + result = -PTR_ERR(clnt4);
>>>>> + rpc_shutdown_client(clnt);
>>>>> + goto out;
>>>>> + }
>>>>> +
>>>>> + rpcb_local_clnt = clnt;
>>>>> + rpcb_local_clnt4 = clnt4;
>>>>> +
>>>>> +out:
>>>>> + spin_unlock(&rpcb_create_local_lock);
>>>>> + return result;
>>>>> }
>>>>
>>>> You can't have tested this. At the very least you cannot have done
>>>> so
>>>> with spinlock debugging enabled...
>>>
>>> I moved the rpcb_create_local_lock spinlock out of the function,
>>> enabled
>>> every spinlock checkbox I could under kernel hacking,
>>
>> Including CONFIG_DEBUG_SPINLOCK_SLEEP?
>
> Yes. I even rebuilt the kernel under test from scratch.
>
>>> and gave the guest
>>> 2 CPUs. The spinlock checker reported a problem almost immediately
>>> with
>>> XFS (even with just one virtual CPU), so I know it's enabled and
>>> working.
>>>
>>> I can't reproduce any problems with the rpcbind upcall here. Do you
>>> have anything more specific?
>>
>> Isn't there an rpc ping in rpc_bind_new_program?
>
> Hrm, I suppose there is. That's weird, clearly I didn't see the
> rpc_ping() call, even though I was looking for it when I wrote this. A
> GFP_KERNEL memory allocation can sleep too, can't it?
Yes. I'd be really curious to know how that got through--if
CONFIG_DEBUG_SPINLOCK_SLEEP can't catch a case that cut-and-dried, then
it's totally broken....
--b.
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