From owner-freebsd-current  Mon Feb 11 19:48:12 2002
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Date: Mon, 11 Feb 2002 09:49:49 -0500 (EST)
From: John Baldwin <jhb@FreeBSD.org>
To: Bruce Evans <bde@zeta.org.au>
Subject: Re: final ucred patch
Cc: current@FreeBSD.ORG, Julian Elischer <julian@elischer.org>
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On 10-Feb-02 Bruce Evans wrote:
>> +                    }
>> +                    if (p->p_ucred) {
> 
> How can this be NULL?  The old code didn't check.

Agreed.  Julian, can you take it out and replace it with a KASSERT() instead
and then get a traceback of the panic?

>>              switch (type) {
>>              case T_PRIVINFLT:       /* privileged instruction fault */
>> @@ -644,10 +654,12 @@
>>      userret(td, &frame, sticks);
>>      mtx_assert(&Giant, MA_NOTOWNED);
>>  userout:
>> +#ifdef      INVARIANTS
>>      mtx_lock(&Giant);
>>      crfree(td->td_ucred);
>> -    mtx_unlock(&Giant);
>>      td->td_ucred = NULL;
>> +    mtx_unlock(&Giant);
>> +#endif
>>  out:
>>      return;
>>  }
> 
> I think moving the unlock is just an obfuscation.  td_ucred isn't locked
> by Giant.

Yep, definitely agree.

> Bruce

-- 

John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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