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Subject: Re: [PATCH] x86/mm: fix use-after-free of ldt_struct
To: Eric Biggers <ebiggers3@gmail.com>, x86@kernel.org
References: <20170824175029.76040-1-ebiggers3@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Eric Biggers <ebiggers@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@amacapital.net>, Borislav Petkov <bp@alien8.de>,
        Brian Gerst <brgerst@gmail.com>, Christoph Hellwig <hch@lst.de>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Dmitry Vyukov <dvyukov@google.com>, "H . Peter Anvin" <hpa@zytor.com>,
        Ingo Molnar <mingo@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>, Peter Zijlstra <peterz@infradead.org>,
        Rik van Riel <riel@redhat.com>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Thomas Gleixner <tglx@linutronix.de>, stable@vger.kernel.org
From: Dave Hansen <dave.hansen@linux.intel.com>
Message-ID: <43bcad51-b210-c1fa-c729-471fe008ba61@linux.intel.com>
Date: Thu, 24 Aug 2017 10:59:18 -0700
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On 08/24/2017 10:50 AM, Eric Biggers wrote:
> --- a/arch/x86/include/asm/mmu_context.h
> +++ b/arch/x86/include/asm/mmu_context.h
> @@ -148,9 +148,7 @@ static inline int init_new_context(struct task_struct *tsk,
>  		mm->context.execute_only_pkey = -1;
>  	}
>  	#endif
> -	init_new_context_ldt(tsk, mm);
> -
> -	return 0;
> +	return init_new_context_ldt(tsk, mm);
>  }

Sheesh.  That was silly.  Thanks for finding and fixing this!  Feel free
to add my ack on it.