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Date:   Fri, 6 Nov 2020 17:28:02 -0500
From:   "J. Bruce Fields" <bfields@fieldses.org>
To:     Chuck Lever <chuck.lever@oracle.com>
Cc:     linux-nfs@vger.kernel.org
Subject: Re: [PATCH] SUNRPC: Fix general protection fault in
 trace_rpc_xdr_overflow()
Message-ID: <20201106222802.GG26028@fieldses.org>
References: <160346406748.79082.3077185849414818247.stgit@klimt.1015granger.net>
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Also applied.--b.

On Fri, Oct 23, 2020 at 10:41:07AM -0400, Chuck Lever wrote:
> The TP_fast_assign() section is careful enough not to dereference
> xdr->rqst if it's NULL. The TP_STRUCT__entry section is not.
> 
> Fixes: 5582863f450c ("SUNRPC: Add XDR overflow trace event")
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  include/trace/events/sunrpc.h |    8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
> index f45b3c01370c..2477014e3fa6 100644
> --- a/include/trace/events/sunrpc.h
> +++ b/include/trace/events/sunrpc.h
> @@ -655,10 +655,10 @@ TRACE_EVENT(rpc_xdr_overflow,
>  		__field(size_t, tail_len)
>  		__field(unsigned int, page_len)
>  		__field(unsigned int, len)
> -		__string(progname,
> -			 xdr->rqst->rq_task->tk_client->cl_program->name)
> -		__string(procedure,
> -			 xdr->rqst->rq_task->tk_msg.rpc_proc->p_name)
> +		__string(progname, xdr->rqst ?
> +			 xdr->rqst->rq_task->tk_client->cl_program->name : "unknown")
> +		__string(procedure, xdr->rqst ?
> +			 xdr->rqst->rq_task->tk_msg.rpc_proc->p_name : "unknown")
>  	),
>  
>  	TP_fast_assign(
>