Re: oops in rpc_pipe_release

[Vince Busam <vbusam@google.com>]

I tried that with and without the linux-2.6.13-CITI_NFS4_ALL-1.dif patch, and either way 
it ends up causing another NULL pointer dereference in __rpc_purge_upcall after an hour or 
two.

Vince

Steve Dickson wrote:
> 
> 
> Vince Busam wrote:
> 
>> I'm using NFS3 with kerberos authentication, and 25 hour tickets that 
>> refresh when
>> unlocking the screensaver.  Over the weekend, it'll hang with one of 
>> the following stack
>> traces.  Any ideas what could cause this?
> 
> I believe this is caused by the fact gss_pipe_release()
> (i.e. rpci->ops->release_pipe(inode)) is being called
> with a freed clnt->cl_auth pointer. I proposed the
> following patch a while back that I thought fixed the
> problem, but Trond said the patch "prevents anyone from
> reopening the pipe after the first close(), so if gssd
> needs to be restarted, then all pipes will forever block."
> So the patch got reverted....
> 
> 
> --- linux-2.6.13/net/sunrpc/rpc_pipe.c.orig    2005-08-28 
> 19:41:01.000000000 -0400
> +++ linux-2.6.13/net/sunrpc/rpc_pipe.c    2005-09-16 11:18:53.598157000 
> -0400
> @@ -177,6 +177,8 @@ rpc_pipe_release(struct inode *inode, st
>          __rpc_purge_upcall(inode, -EPIPE);
>      if (rpci->ops->release_pipe)
>          rpci->ops->release_pipe(inode);
> +    if (!rpci->nreaders && !rpci->nwriters)
> +        rpci->ops = NULL;
>  out:
>      up(&inode->i_sem);
>      return 0;
> 
> I think the main problem here is there is no way of telling
> if a rpc_inode is or is not valid (or active) so there
> is no way of knowing whether or not a release call is needed...
> 
> steved.


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