From: Sasha Levin <sashal@kernel.org>
To: shakeel.butt@linux.dev
Cc: Sasha Levin <sashal@kernel.org>,
akpm@linux-foundation.org, baohua@kernel.org,
cgroups@vger.kernel.org, chenxinxin@xiaomi.com, david@kernel.org,
david@redhat.com, gregkh@linuxfoundation.org, hannes@cmpxchg.org,
hughd@google.com, jose.fernandez@linux.dev,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
mambaxin@163.com, mhocko@kernel.org, muchun.song@linux.dev,
roman.gushchin@linux.dev, ryncsn@gmail.com, shakeelb@google.com,
stable@vger.kernel.org,
syzbot+e12bd9ca48157add237a@syzkaller.appspotmail.com,
v-songbaohua@oppo.com
Subject: Re: [PATCH] mm: swap_cgroup: fix NULL deref in lookup_swap_cgroup_id on swapless host
Date: Mon, 17 Aug 2026 11:24:42 -0400 [thread overview]
Message-ID: <20260817150000.4@kernel.org> (raw)
In-Reply-To: <20260817032622.1135640-1-mambaxin@163.com>
> Yes, we would like to backport this patch to the 6.6.y stable tree.
> We have encountered the same issue on a product running the Android GKI 6.6 kernel.
This is not a 6.6.y fix. The NULL deref is only reachable through the
batching added by bea67dcc5eea ("mm: attempt to batch free swap entries
for zap_pte_range()"), which is v6.12 and newer. 6.6.y has no
swap_pte_batch() at all, so the exit_mmap -> zap_pte_range ->
lookup_swap_cgroup_id path you are hitting does not exist there and the
guard would be dead code.
Your oops is on Android GKI 6.6, which carries the batching backport
downstream - that is the tree that should carry this fix, alongside the
commit that makes it reachable.
--
Thanks,
Sasha
next prev parent reply other threads:[~2026-08-17 15:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-14 7:47 [PATCH] mm: swap_cgroup: fix NULL deref in lookup_swap_cgroup_id on swapless host mambaxin
2026-08-14 11:23 ` Barry Song
2026-08-15 0:36 ` Shakeel Butt
2026-08-17 3:26 ` mambaxin
2026-08-17 15:24 ` Sasha Levin [this message]
-- strict thread matches above, loose matches on Subject: below --
2026-05-04 12:55 Jose Fernandez (Anthropic)
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