Patch "gve: Clear napi->skb before dev_kfree_skb_any()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    gve: Clear napi->skb before dev_kfree_skb_any()

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     gve-clear-napi-skb-before-dev_kfree_skb_any.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 8bbf589b0d69a6a3c06ce2d3d74d1eb1ebfde414
Author: Ziwei Xiao <ziweixiao@xxxxxxxxxx>
Date:   Wed Jun 12 00:16:54 2024 +0000

    gve: Clear napi->skb before dev_kfree_skb_any()
    
    [ Upstream commit 6f4d93b78ade0a4c2cafd587f7b429ce95abb02e ]
    
    gve_rx_free_skb incorrectly leaves napi->skb referencing an skb after it
    is freed with dev_kfree_skb_any(). This can result in a subsequent call
    to napi_get_frags returning a dangling pointer.
    
    Fix this by clearing napi->skb before the skb is freed.
    
    Fixes: 9b8dd5e5ea48 ("gve: DQO: Add RX path")
    Cc: stable@xxxxxxxxxxxxxxx
    Reported-by: Shailend Chand <shailend@xxxxxxxxxx>
    Signed-off-by: Ziwei Xiao <ziweixiao@xxxxxxxxxx>
    Reviewed-by: Harshitha Ramamurthy <hramamurthy@xxxxxxxxxx>
    Reviewed-by: Shailend Chand <shailend@xxxxxxxxxx>
    Reviewed-by: Praveen Kaligineedi <pkaligineedi@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240612001654.923887-1-ziweixiao@xxxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/google/gve/gve_rx_dqo.c b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
index 630f42a3037b0..8756f9cbd631e 100644
--- a/drivers/net/ethernet/google/gve/gve_rx_dqo.c
+++ b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
@@ -465,11 +465,13 @@ static void gve_rx_skb_hash(struct sk_buff *skb,
 	skb_set_hash(skb, le32_to_cpu(compl_desc->hash), hash_type);
 }
 
-static void gve_rx_free_skb(struct gve_rx_ring *rx)
+static void gve_rx_free_skb(struct napi_struct *napi, struct gve_rx_ring *rx)
 {
 	if (!rx->ctx.skb_head)
 		return;
 
+	if (rx->ctx.skb_head == napi->skb)
+		napi->skb = NULL;
 	dev_kfree_skb_any(rx->ctx.skb_head);
 	rx->ctx.skb_head = NULL;
 	rx->ctx.skb_tail = NULL;
@@ -690,7 +692,7 @@ int gve_rx_poll_dqo(struct gve_notify_block *block, int budget)
 
 		err = gve_rx_dqo(napi, rx, compl_desc, rx->q_num);
 		if (err < 0) {
-			gve_rx_free_skb(rx);
+			gve_rx_free_skb(napi, rx);
 			u64_stats_update_begin(&rx->statss);
 			if (err == -ENOMEM)
 				rx->rx_skb_alloc_fail++;
@@ -733,7 +735,7 @@ int gve_rx_poll_dqo(struct gve_notify_block *block, int budget)
 
 		/* gve_rx_complete_skb() will consume skb if successful */
 		if (gve_rx_complete_skb(rx, napi, compl_desc, feat) != 0) {
-			gve_rx_free_skb(rx);
+			gve_rx_free_skb(napi, rx);
 			u64_stats_update_begin(&rx->statss);
 			rx->rx_desc_err_dropped_pkt++;
 			u64_stats_update_end(&rx->statss);