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Date:   Sat, 15 Jul 2023 09:54:19 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Zheng Yejian <zhengyejian1@huawei.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH 2/2] tracing: Add free_trace_iter_content() helper
 function
Message-ID: <20230715095419.3af9ec19@rorschach.local.home>
In-Reply-To: <20230715094201.34a41f17@rorschach.local.home>
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        <20230713114700.450e7a17@gandalf.local.home>
        <d8aeab6c-338e-dcdd-75c6-7ae4eb9c9887@huawei.com>
        <20230715094201.34a41f17@rorschach.local.home>
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On Sat, 15 Jul 2023 09:42:01 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Sat, 15 Jul 2023 13:15:32 +0800
> Zheng Yejian <zhengyejian1@huawei.com> wrote:
> 
> > > @@ -6709,7 +6723,12 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
> > >   	}
> > >   
> > >   	trace_seq_init(&iter->seq);
> > > -	iter->trace = tr->current_trace;
> > > +
> > > +	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
> > > +	if (!iter->trace)
> > > +		goto fail;  
> > 
> > Hi, Steve, 'ret' may need to be set before `goto fail`:
> >    ret = -ENOMEM;
> > 
> 
> As I mentioned to Masami, this hunk of the patch didn't belong.
> Something got mixed up in the commit. This patch even depends on the
> previous patch to remove the allocation completely.
> 

I know what I did now. I first started writing this patch and saw that
the iter->trace was inconsistent and in one place allocated a copy and
here it did not. I started to make the copy here, when I realized that
there was no reason to make that copy. Then I wrote the first patch to
remove the copying, but forgot to remove the copying I added in this
patch! :-p

-- Steve