diff options
| author | Max Yuan <maxyuan@google.com> | 2025-11-27 00:07:51 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-11-27 17:44:52 -0800 |
| commit | 858b1d07e49106a302cc7c7fbeee4fb2698573c9 (patch) | |
| tree | f6ced59e75aa7a0866b45bcf399f92ac3bdbd702 /drivers | |
| parent | 4c03592689bc19df9deda7a33d56c6ac0cec8651 (diff) | |
| download | linux-858b1d07e49106a302cc7c7fbeee4fb2698573c9.tar.gz | |
gve: Fix race condition on tx->dropped_pkt update
The tx->dropped_pkt counter is a 64-bit integer that is incremented
directly. On 32-bit architectures, this operation is not atomic and
can lead to read/write tearing if a reader accesses the counter during
the update. This can result in incorrect values being reported for
dropped packets.
To prevent this potential data corruption, wrap the increment
operation with u64_stats_update_begin() and u64_stats_update_end().
This ensures that updates to the 64-bit counter are atomic, even on
32-bit systems, by using a sequence lock.
The u64_stats_sync API requires the writer to have exclusive access,
which is already provided in this context by the network stack's
serialization of the transmit path (net_device_ops::ndo_start_xmit
[1]) for a given queue.
[1]: https://www.kernel.org/doc/Documentation/networking/netdevices.txt
Signed-off-by: Max Yuan <maxyuan@google.com>
Reviewed-by: Jordan Rhee <jordanrhee@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/ethernet/google/gve/gve_tx.c | 2 | ||||
| -rw-r--r-- | drivers/net/ethernet/google/gve/gve_tx_dqo.c | 6 |
2 files changed, 8 insertions, 0 deletions
diff --git a/drivers/net/ethernet/google/gve/gve_tx.c b/drivers/net/ethernet/google/gve/gve_tx.c index c6ff0968929d61..97efc8d27e6f74 100644 --- a/drivers/net/ethernet/google/gve/gve_tx.c +++ b/drivers/net/ethernet/google/gve/gve_tx.c @@ -730,7 +730,9 @@ unmap_drop: gve_tx_unmap_buf(tx->dev, &tx->info[idx & tx->mask]); } drop: + u64_stats_update_begin(&tx->statss); tx->dropped_pkt++; + u64_stats_update_end(&tx->statss); return 0; } diff --git a/drivers/net/ethernet/google/gve/gve_tx_dqo.c b/drivers/net/ethernet/google/gve/gve_tx_dqo.c index 6f1d515673d25a..40b89b3e5a318a 100644 --- a/drivers/net/ethernet/google/gve/gve_tx_dqo.c +++ b/drivers/net/ethernet/google/gve/gve_tx_dqo.c @@ -1002,7 +1002,9 @@ static int gve_try_tx_skb(struct gve_priv *priv, struct gve_tx_ring *tx, return 0; drop: + u64_stats_update_begin(&tx->statss); tx->dropped_pkt++; + u64_stats_update_end(&tx->statss); dev_kfree_skb_any(skb); return 0; } @@ -1324,7 +1326,11 @@ static void remove_miss_completions(struct gve_priv *priv, /* This indicates the packet was dropped. */ dev_kfree_skb_any(pending_packet->skb); pending_packet->skb = NULL; + + u64_stats_update_begin(&tx->statss); tx->dropped_pkt++; + u64_stats_update_end(&tx->statss); + net_err_ratelimited("%s: No reinjection completion was received for: %d.\n", priv->dev->name, (int)(pending_packet - tx->dqo.pending_packets)); |