Message-id: <55800C42.4050702@samsung.com>
Date: Tue, 16 Jun 2015 14:45:06 +0300
From: Andrey Ryabinin <a.ryabinin@samsung.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101
 Thunderbird/31.7.0
MIME-version: 1.0
To: Borislav Petkov <bp@alien8.de>, Alexander Popov <alpopov@ptsecurity.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andrey Konovalov <adech.fo@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Alexander Kuleshov <kuleshovmail@gmail.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Kees Cook <keescook@chromium.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 1/2] x86_64: remove not needed clear_page for
 init_level4_page
References: <1433842921-18055-1-git-send-email-alpopov@ptsecurity.com>
 <1433842921-18055-2-git-send-email-alpopov@ptsecurity.com>
 <20150616111632.GF17786@pd.tnic> <20150616113436.GG17786@pd.tnic>
In-reply-to: <20150616113436.GG17786@pd.tnic>
Content-type: text/plain; charset=utf-8
Content-transfer-encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 800
Lines: 24

On 06/16/2015 02:34 PM, Borislav Petkov wrote:
> On Tue, Jun 16, 2015 at 01:16:32PM +0200, Borislav Petkov wrote:
>> Now my hunch is that those entries get overwritten later but I wouldn't
>> want to debug any strange bugs from leftovers in init_level4_pgt so
>> having the clear_page() is actually a good thing.
> 
> So I guess we can do that:
> 
> #ifndef CONFIG_KASAN
>         clear_page(init_level4_pgt);
> #endif
> 

Ugh..

Can't we just move clear_page(init_level4_pgt) higher? Before or right after clear_bss() (iow before kasan_early_init()).


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/