Received-SPF: pass (google.com: domain of linux-kernel+bounces-194353-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Wed, 29 May 2024 16:21:23 +0100
From: Will Deacon <will@kernel.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org,
	linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Barry Song <v-songbaohua@oppo.com>,
	Lance Yang <ioworker0@gmail.com>,
	Ryan Roberts <ryan.roberts@arm.com>,
	David Hildenbrand <david@redhat.com>,
	Jeff Xie <xiehuan09@gmail.com>,
	Kefeng Wang <wangkefeng.wang@huawei.com>,
	Michal Hocko <mhocko@suse.com>, Minchan Kim <minchan@kernel.org>,
	Muchun Song <songmuchun@bytedance.com>,
	Peter Xu <peterx@redhat.com>, Yang Shi <shy828301@gmail.com>,
	Yin Fengwei <fengwei.yin@intel.com>,
	Zach O'Keefe <zokeefe@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: [PATCH] mm: arm64: Fix the out-of-bounds issue in
 contpte_clear_young_dirty_ptes
Message-ID: <20240529152123.GA13782@willie-the-truck>
References: <20240524005444.135417-1-21cnbao@gmail.com>
 <ZlWVHC0e2OadjwIa@J2N7QTR9R3>
 <CAGsJ_4xMdyBxwwh1AQeFM5a_ZMV2=y68M9eEuJf-D6NtYP-8dA@mail.gmail.com>
 <ZldCwWqI0JVIqh_3@J2N7QTR9R3.cambridge.arm.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <ZldCwWqI0JVIqh_3@J2N7QTR9R3.cambridge.arm.com>
User-Agent: Mutt/1.10.1 (2018-07-13)

On Wed, May 29, 2024 at 03:59:13PM +0100, Mark Rutland wrote:
> On Tue, May 28, 2024 at 08:39:55PM +1200, Barry Song wrote:
> > On Tue, May 28, 2024 at 8:26 PM Mark Rutland <mark.rutland@arm.com> wrote:
> > > On Fri, May 24, 2024 at 12:54:44PM +1200, Barry Song wrote:
> > > > From: Barry Song <v-songbaohua@oppo.com>
> > > >
> > > > We are passing a huge nr to __clear_young_dirty_ptes() right
> > > > now. While we should pass the number of pages, we are actually
> > > > passing CONT_PTE_SIZE. This is causing lots of crashes of
> > > > MADV_FREE, panic oops could vary everytime.
> > > >
> > > > Fixes: 89e86854fb0a ("mm/arm64: override clear_young_dirty_ptes() batch helper")
> > >
> > > I was seeing ths same thing on v6.10-rc1 (syzkaller splat and reproducer
> > > included at the end of the mail). The patch makes sense to me, and fixed the
> > > splat in testing, so:
> > >
> > > Reviewed-by: Mark Rutland <mark.rutland@arm.com>
> > > Tested-by: Mark Rutland <mark.rutland@arm.com>
> > 
> > Thanks!
> > 
> > > Since this only affects arm64 and is already in mainline, I assume the fix
> > > should go via the arm64 tree even though the broken commit went via mm.
> > 
> > Either mm or arm64 is fine with me, but I noticed that Andrew has already
> > included it in mm-hotfixes-unstable. If it works, we may want to stick with
> > that. :-)
> 
> Going via mm is also fine by me, I had just expected it'd be quicker to
> go via arm64 (and evidently I was wrong there!). :)

Sorry, I was fishing! I'm happy for it to land via -mm.

Will