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[2a0c:4d80:42:443::2]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4887a2acb4dsm27519158f8f.0.2026.09.28.06.58.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Sep 2026 06:58:41 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 856EDA0FCDD; Mon, 28 Sep 2026 14:40:22 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Mina Almasry , Alexander Lobakin , Jakub Kicinski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Mina Almasry , Jesper Dangaard Brouer , Ilias Apalodimas , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Kaifeng Wang , Dong Chenchen Subject: Re: [PATCH net v1] net: page_pool: fix use-after-free in page_pool_recycle_ring_bulk() In-Reply-To: <20260925144127.1445667-1-almasrymina@google.com> References: <20260925144127.1445667-1-almasrymina@google.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Mon, 28 Sep 2026 14:40:22 +0200 Message-ID: <871padlfbd.fsf@toke.dk> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mina Almasry writes: > With CONFIG_PAGE_POOL_STATS=3Dy, page_pool_recycle_ring_bulk() updates > the recycle stats after dropping the producer lock. If it just recycled > the last inflight netmems of a pool being destroyed, page_pool_release() > can pass its producer-lock barrier and free the pool before > recycle_stat_add() runs. > > Commit fcc680a647ba7 ("page_pool: allow mixing PPs within one bulk") > moved this stat update after the unlock. Commit 271683bb2cf32 > ("page_pool: Fix use-after-free in page_pool_recycle_in_ring") later > added the barrier, but only fixed page_pool_recycle_in_ring(). Move > the update back under the lock. > > Fixes: fcc680a647ba7 ("page_pool: allow mixing PPs within one bulk") > Link: https://lore.kernel.org/r/179028939171.2160803.706522228583664641@k= ernel.org > Cc: Kaifeng Wang > Cc: Dong Chenchen > Assisted-by: LLM > Signed-off-by: Mina Almasry Reviewed-by: Toke H=C3=B8iland-J=C3=B8rgensen