From: Ciara Loftus ciara.loftus@intel.com

mainline inclusion from mainline-v5.16-rc8 commit 5bec7ca2be6955ca1aa0d7bae2b981de9b1c9844 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7UZT5

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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This commit initialises the xskb's free_list_node when the xskb is allocated. This prevents a potential false negative returned from a call to list_empty for that node, such as the one introduced in commit 199d983bc015 ("xsk: Fix crash on double free in buffer pool")

In my environment this issue caused packets to not be received by the xdpsock application if the traffic was running prior to application launch. This happened when the first batch of packets failed the xskmap lookup and XDP_PASS was returned from the bpf program. This action is handled in the i40e zc driver (and others) by allocating an skbuff, freeing the xdp_buff and adding the associated xskb to the xsk_buff_pool's free_list if it hadn't been added already. Without this fix, the xskb is not added to the free_list because the check to determine if it was added already returns an invalid positive result. Later, this caused allocation errors in the driver and the failure to receive packets.

Fixes: 199d983bc015 ("xsk: Fix crash on double free in buffer pool") Fixes: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API") Signed-off-by: Ciara Loftus ciara.loftus@intel.com Acked-by: Magnus Karlsson magnus.karlsson@intel.com Link: https://lore.kernel.org/r/20211220155250.2746-1-ciara.loftus@intel.com Signed-off-by: Jakub Kicinski kuba@kernel.org

Conflicts: net/xdp/xsk_buff_pool.c

Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com --- net/xdp/xsk_buff_pool.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c index c347e52f58df..383c083faa01 100644 --- a/net/xdp/xsk_buff_pool.c +++ b/net/xdp/xsk_buff_pool.c @@ -81,6 +81,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs, xskb = &pool->heads[i]; xskb->pool = pool; xskb->xdp.frame_sz = umem->chunk_size - umem->headroom; + INIT_LIST_HEAD(&xskb->free_list_node); pool->free_heads[i] = xskb; }