[PATCH 6.6 371/567] gve: fix incorrect buffer cleanup in gve_tx_clean_pending_packets for QPL

Greg Kroah-Hartman
2026-03-23T15:11:30Z

6.6-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ankit Garg <nktgrg@google.com>

[ Upstream commit fb868db5f4bccd7a78219313ab2917429f715cea ]

In DQ-QPL mode, gve_tx_clean_pending_packets() incorrectly uses the RDA
buffer cleanup path. It iterates num_bufs times and attempts to unmap
entries in the dma array.

This leads to two issues:
1. The dma array shares storage with tx_qpl_buf_ids (union).
Interpreting buffer IDs as DMA addresses results in attempting to
unmap incorrect memory locations.
2. num_bufs in QPL mode (counting 2K chunks) can significantly exceed
the size of the dma array, causing out-of-bounds access warnings
(trace below is how we noticed this issue).

UBSAN: array-index-out-of-bounds in
drivers/net/ethernet/drivers/net/ethernet/google/gve/gve_tx_dqo.c:178:5 index 18 is out of
range for type 'dma_addr_t[18]' (aka 'unsigned long long[18]')
Workqueue: gve gve_service_task [gve]
Call Trace:
<TASK>
dump_stack_lvl+0x33/0xa0
__ubsan_handle_out_of_bounds+0xdc/0x110
gve_tx_stop_ring_dqo+0x182/0x200 [gve]
gve_close+0x1be/0x450 [gve]
gve_reset+0x99/0x120 [gve]
gve_service_task+0x61/0x100 [gve]
process_scheduled_works+0x1e9/0x380

Fix this by properly checking for QPL mode and delegating to
gve_free_tx_qpl_bufs() to reclaim the buffers.

Cc: stable@vger.kernel.org
Fixes: a6fb8d5a8b69 ("gve: Tx path for DQO-QPL")
Signed-off-by: Ankit Garg <nktgrg@google.com>
Reviewed-by: Jordan Rhee <jordanrhee@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: Joshua Washington <joshwash@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260220215324.1631350-1-joshwash@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ netmem_dma_unmap_page_attrs() => dma_unmap_page() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/google/gve/gve_tx_dqo.c | 52 +++++++++++----------------
1 file changed, 23 insertions(+), 29 deletions(-)

--- a/drivers/net/ethernet/google/gve/gve_tx_dqo.c
+++ b/drivers/net/ethernet/google/gve/gve_tx_dqo.c
@@ -157,6 +157,24 @@ gve_free_pending_packet(struct gve_tx_ri
}
}

+static void gve_unmap_packet(struct device *dev,
+ struct gve_tx_pending_packet_dqo *pkt)
+{
+ int i;
+
+ if (!pkt->num_bufs)
+ return;
+
+ /* SKB linear portion is guaranteed to be mapped */
+ dma_unmap_single(dev, dma_unmap_addr(pkt, dma[0]),
+ dma_unmap_len(pkt, len[0]), DMA_TO_DEVICE);
+ for (i = 1; i < pkt->num_bufs; i++) {
+ dma_unmap_page(dev, dma_unmap_addr(pkt, dma[i]),
+ dma_unmap_len(pkt, len[i]), DMA_TO_DEVICE);
+ }
+ pkt->num_bufs = 0;
+}
+
/* gve_tx_free_desc - Cleans up all pending tx requests and buffers.
*/
static void gve_tx_clean_pending_packets(struct gve_tx_ring *tx)
@@ -166,21 +184,12 @@ static void gve_tx_clean_pending_packets
for (i = 0; i < tx->dqo.num_pending_packets; i++) {
struct gve_tx_pending_packet_dqo *cur_state =
&tx->dqo.pending_packets[i];
- int j;

- for (j = 0; j < cur_state->num_bufs; j++) {
- if (j == 0) {
- dma_unmap_single(tx->dev,
- dma_unmap_addr(cur_state, dma[j]),
- dma_unmap_len(cur_state, len[j]),
- DMA_TO_DEVICE);
- } else {
- dma_unmap_page(tx->dev,
- dma_unmap_addr(cur_state, dma[j]),
- dma_unmap_len(cur_state, len[j]),
- DMA_TO_DEVICE);
- }
- }
+ if (tx->dqo.qpl)
+ gve_free_tx_qpl_bufs(tx, cur_state);
+ else
+ gve_unmap_packet(tx->dev, cur_state);
+
if (cur_state->skb) {
dev_consume_skb_any(cur_state->skb);
cur_state->skb = NULL;
@@ -992,21 +1001,6 @@ static void remove_from_list(struct gve_
}
}

-static void gve_unmap_packet(struct device *dev,
- struct gve_tx_pending_packet_dqo *pkt)
-{
- int i;
-
- /* SKB linear portion is guaranteed to be mapped */
- dma_unmap_single(dev, dma_unmap_addr(pkt, dma[0]),
- dma_unmap_len(pkt, len[0]), DMA_TO_DEVICE);
- for (i = 1; i < pkt->num_bufs; i++) {
- dma_unmap_page(dev, dma_unmap_addr(pkt, dma[i]),
- dma_unmap_len(pkt, len[i]), DMA_TO_DEVICE);
- }
- pkt->num_bufs = 0;
-}
-
/* Completion types and expected behavior:
* No Miss compl + Packet compl = Packet completed normally.
* Miss compl + Re-inject compl = Packet completed normally.