Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 4 Jan 2023 12:58:48 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     Ross Philipson <ross.philipson@oracle.com>,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        dpsmith@apertussolutions.com, tglx@linutronix.de, mingo@redhat.com,
        hpa@zytor.com, luto@amacapital.net, dave.hansen@linux.intel.com,
        kanth.ghatraju@oracle.com, trenchboot-devel@googlegroups.com,
        jailhouse-dev@googlegroups.com, jan.kiszka@siemens.com,
        xen-devel@lists.xenproject.org, jgross@suse.com,
        boris.ostrovsky@oracle.com, andrew.cooper3@citrix.com
Subject: Re: [PATCH v2 1/2] x86: Check return values from early_memremap calls
Message-ID: <Y7Vp+EPq5wkGr5mi@zn.tnic>
References: <20221110154521.613472-1-ross.philipson@oracle.com>
 <20221110154521.613472-2-ross.philipson@oracle.com>
 <8e62a029-f2fa-0627-1f71-4850a68ec6b6@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <8e62a029-f2fa-0627-1f71-4850a68ec6b6@intel.com>
Precedence: bulk

On Thu, Nov 10, 2022 at 08:07:53AM -0800, Dave Hansen wrote:
> On 11/10/22 07:45, Ross Philipson wrote:
> >  	dt = early_memremap(initial_dtb, map_len);
> > +	if (!dt) {
> > +		pr_warn("failed to memremap initial dtb\n");
> > +		return;
> > +	}
> 
> Are all of these new pr_warn/err()'s really adding much value?  They all
> look pretty generic.  It makes me wonder if we should just spit out a
> generic message in early_memremap() and save all the callers the trouble.

Well, let's see.

early_memremap() calls __early_ioremap() and that one already warns befofe each
NULL return. So I guess we don't need the error messages as we will know where
it starts failing.

I guess we still need the error handling though.

I.e., this above should be:

    dt = early_memremap(initial_dtb, map_len);
+   if (!dt)
+           return;

so that we don't go off into the weeds with a NULL ptr.

Or?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette