diff options
| author | Jesper Dangaard Brouer <hawk@kernel.org> | 2025-06-11 14:40:04 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-06-12 08:08:32 -0700 |
| commit | 9337c54401a5bb6ac3c9f6c71dd2a9130cfba82e (patch) | |
| tree | e8e037d9be70415c3c1111c1d7bcbadd5a23127e | |
| parent | a844b0c864a28e43affa3f1a048414b7122def40 (diff) | |
veth: prevent NULL pointer dereference in veth_xdp_rcv
The veth peer device is RCU protected, but when the peer device gets
deleted (veth_dellink) then the pointer is assigned NULL (via
RCU_INIT_POINTER).
This patch adds a necessary NULL check in veth_xdp_rcv when accessing
the veth peer net_device.
This fixes a bug introduced in commit dc82a33297fc ("veth: apply qdisc
backpressure on full ptr_ring to reduce TX drops"). The bug is a race
and only triggers when having inflight packets on a veth that is being
deleted.
Reported-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Closes: https://lore.kernel.org/all/fecfcad0-7a16-42b8-bff2-66ee83a6e5c4@linux.dev/
Reported-by: syzbot+c4c7bf27f6b0c4bd97fe@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/683da55e.a00a0220.d8eae.0052.GAE@google.com/
Fixes: dc82a33297fc ("veth: apply qdisc backpressure on full ptr_ring to reduce TX drops")
Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://patch.msgid.link/174964557873.519608.10855046105237280978.stgit@firesoul
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/veth.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/veth.c b/drivers/net/veth.c index e58a0f1b5c5b..a3046142cb8e 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -909,7 +909,7 @@ static int veth_xdp_rcv(struct veth_rq *rq, int budget, /* NAPI functions as RCU section */ peer_dev = rcu_dereference_check(priv->peer, rcu_read_lock_bh_held()); - peer_txq = netdev_get_tx_queue(peer_dev, queue_idx); + peer_txq = peer_dev ? netdev_get_tx_queue(peer_dev, queue_idx) : NULL; for (i = 0; i < budget; i++) { void *ptr = __ptr_ring_consume(&rq->xdp_ring); @@ -959,7 +959,7 @@ static int veth_xdp_rcv(struct veth_rq *rq, int budget, rq->stats.vs.xdp_packets += done; u64_stats_update_end(&rq->stats.syncp); - if (unlikely(netif_tx_queue_stopped(peer_txq))) + if (peer_txq && unlikely(netif_tx_queue_stopped(peer_txq))) netif_tx_wake_queue(peer_txq); return done; |