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Date:   Fri, 20 Jan 2023 12:13:38 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Dan Carpenter <error27@gmail.com>
Cc:     "Ismail, Mustafa" <mustafa.ismail@intel.com>,
        Leon Romanovsky <leon@kernel.org>,
        "Latif, Faisal" <faisal.latif@intel.com>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [bug report] iwpm: crash fix for large connections test
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On Mon, Nov 28, 2022 at 10:34:17AM +0300, Dan Carpenter wrote:
> So the background here is that Smatch sees this:
> 
> 	kref_put(&nlmsg_request->kref, iwpm_free_nlmsg_request);
> 
> and correctly says "if we call iwpm_free_nlmsg_request() then
> dereferencing nlmsg_request is a use after free".  However, the code
> is holding two references at this point so it will never call
> iwpm_free_nlmsg_request().
> 
> Smatch already checks to see if we are holding two references, but it
> doesn't parse this code correctly.  Smatch could be fixed, but there are
> other places with similar warnings that are more difficult to fix.
> 
> What we could do is create a kref_no_release() function that just calls
> WARN().  This would silence the warning and, I think, this would make
> the code more readable.
> 
> What do other people think?

Sure, that looks semi-decent if it helps out with the automated tools.

thanks

greg k-h