From bdea4980182e3badac74f04df6c07492b91c569e Mon Sep 17 00:00:00 2001 From: Mina Almasry Date: Fri, 25 Sep 2026 14:41:11 +0000 Subject: [PATCH] net: page_pool: fix use-after-free in page_pool_recycle_ring_bulk() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With CONFIG_PAGE_POOL_STATS=y, 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@kernel.org Cc: Kaifeng Wang Cc: Dong Chenchen Signed-off-by: Mina Almasry Reviewed-by: Simon Horman Reviewed-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20260925144127.1445667-1-almasrymina@google.com Signed-off-by: Jakub Kicinski --- net/core/page_pool.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 08d7f35cf608..d7c88c0b67e5 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -951,8 +951,8 @@ static void page_pool_recycle_ring_bulk(struct page_pool *pool, } } - page_pool_producer_unlock(pool, in_softirq); recycle_stat_add(pool, ring, i); + page_pool_producer_unlock(pool, in_softirq); /* Hopefully all pages were returned into ptr_ring */ if (likely(i == bulk_len))