[lvc-project] [PATCH v2 1/2] wifi: ath12k: annotate skb of struct ath12k_ce_ring with __counted_by

[Dmitry Antipov]

According to 'ath12k_ce_alloc_ring()', annotate flexible array
member 'skb' of 'struct ath12k_ce_ring' with '__counted_by()'
to improve runtime bounds checking when CONFIG_UBSAN_BOUNDS is
enabled. Compile tested only.

Signed-off-by: Dmitry Antipov <dmantipov at yandex.ru>
---
v2: add related comment in ath12k_ce_alloc_ring()
---
 drivers/net/wireless/ath/ath12k/ce.c | 3 +++
 drivers/net/wireless/ath/ath12k/ce.h | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/ce.c b/drivers/net/wireless/ath/ath12k/ce.c
index be0d669d31fc..23d984da2341 100644
--- a/drivers/net/wireless/ath/ath12k/ce.c
+++ b/drivers/net/wireless/ath/ath12k/ce.c
@@ -550,6 +550,9 @@ ath12k_ce_alloc_ring(struct ath12k_base *ab, int nentries, int desc_sz)
 	if (!ce_ring)
 		return ERR_PTR(-ENOMEM);
 
+	/* Note nentries should be set before populating skb[],
+	 * otherwise __counted_by() might raise false positives.
+	 */
 	ce_ring->nentries = nentries;
 	ce_ring->nentries_mask = nentries - 1;
 
diff --git a/drivers/net/wireless/ath/ath12k/ce.h b/drivers/net/wireless/ath/ath12k/ce.h
index 857bc5f9e946..6967e3891030 100644
--- a/drivers/net/wireless/ath/ath12k/ce.h
+++ b/drivers/net/wireless/ath/ath12k/ce.h
@@ -135,7 +135,7 @@ struct ath12k_ce_ring {
 	u32 hal_ring_id;
 
 	/* keep last */
-	struct sk_buff *skb[];
+	struct sk_buff *skb[] __counted_by(nentries);
 };
 
 struct ath12k_ce_pipe {
-- 
2.47.0