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[111.246.111.57]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b0bc881bacsm28941455ad.46.2026.03.26.05.42.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2026 05:42:59 -0700 (PDT) Date: Thu, 26 Mar 2026 20:42:55 +0800 From: Hao-Yu Yang To: Eric Dumazet Cc: Peter Zijlstra , "David Hildenbrand (Arm)" , Thomas Gleixner , mingo@redhat.com, linux-kernel@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, Lorenzo Stoakes , "Liam R. Howlett" Subject: Re: [PATCH v2] futex: Use-after-free between futex_key_to_node_opt and vma_replace_policy Message-ID: References: <20260313124756.52461-1-naup96721@gmail.com> <87a4vyihlx.ffs@tglx> <20260324140019.GE3738010@noisy.programming.kicks-ass.net> <87fr5pgp5x.ffs@tglx> <20260324174418.GB1850007@noisy.programming.kicks-ass.net> <20260325151445.GH3738010@noisy.programming.kicks-ass.net> <20260325152206.GH3738786@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: I need to send patch v3? If i need how i need to change about this patch? On Wed, Mar 25, 2026 at 08:25:29AM -0700, Eric Dumazet wrote: > On Wed, Mar 25, 2026 at 8:22 AM Peter Zijlstra wrote: > > > Fair enough. Like so then.. > > > > --- a/kernel/futex/core.c > > +++ b/kernel/futex/core.c > > @@ -342,7 +342,7 @@ static int __futex_key_to_node(struct mm > > if (!vma) > > return FUTEX_NO_NODE; > > > > - mpol = vma_policy(vma); > > + mpol = READ_ONCE(vma->vm_policy); > > if (!mpol) > > return FUTEX_NO_NODE; > > > > --- a/mm/mempolicy.c > > +++ b/mm/mempolicy.c > > @@ -1026,7 +1026,7 @@ static int vma_replace_policy(struct vm_ > > } > > > > old = vma->vm_policy; > > - vma->vm_policy = new; /* protected by mmap_lock */ > > + WRITE_ONCE(vma->vm_policy, new); /* protected by mmap_lock */ > > mpol_put(old); > > > > return 0; > > LGTM, thanks ! > > Reviewed-by: Eric Dumazet