From: Mikhail Limarenko <m.limarencko@yandex.ru>

freq_to_idx() currently returns a trailing synthetic index when the
requested channel frequency is not found.

chan-info handlers already bound-check survey index, but an explicit
error on no-match keeps semantics clear and avoids propagating a fake
index value.

Keep matched-frequency index progression unchanged, return -ENOENT on
no match, and make callers reject negative indexes.

Tested-on: QCNFA765 (WCN785x), kernel 6.18.5+deb13-amd64
Signed-off-by: Mikhail Limarenko <m.limarencko@yandex.ru>
---
v2:
- drop out-of-bounds claim from commit message
- keep original index progression for matched frequencies
- return explicit -ENOENT on no-match and reject negative idx in callers

 drivers/net/wireless/ath/ath12k/wmi.c | 9 +++------
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/wmi.c b/drivers/net/wireless/ath/ath12k/wmi.c
index e647b84..a2f8a7c 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.c
+++ b/drivers/net/wireless/ath/ath12k/wmi.c
@@ -6528,12 +6528,11 @@ static int freq_to_idx(struct ath12k *ar, int freq)
 				continue;
 
 			if (sband->channels[ch].center_freq == freq)
-				goto exit;
+				return idx;
 		}
 	}
 
-exit:
-	return idx;
+	return -ENOENT;
 }
 
 static int ath12k_pull_chan_info_ev(struct ath12k_base *ab, struct sk_buff *skb,
@@ -7475,7 +7474,7 @@ static void ath12k_chan_info_event(struct ath12k_base *ab, struct sk_buff *skb)
 	}
 
 	idx = freq_to_idx(ar, le32_to_cpu(ch_info_ev.freq));
-	if (idx >= ARRAY_SIZE(ar->survey)) {
+	if (idx < 0 || idx >= ARRAY_SIZE(ar->survey)) {
 		ath12k_warn(ab, "chan info: invalid frequency %d (idx %d out of bounds)\n",
 			    ch_info_ev.freq, idx);
 		goto exit;
@@ -7550,7 +7549,7 @@ ath12k_pdev_bss_chan_info_event(struct ath12k_base *ab, struct sk_buff *skb)
 
 	spin_lock_bh(&ar->data_lock);
 	idx = freq_to_idx(ar, le32_to_cpu(bss_ch_info_ev.freq));
-	if (idx >= ARRAY_SIZE(ar->survey)) {
+	if (idx < 0 || idx >= ARRAY_SIZE(ar->survey)) {
 		ath12k_warn(ab, "bss chan info: invalid frequency %d (idx %d out of bounds)\n",
 			    bss_ch_info_ev.freq, idx);
 		goto exit;
-- 
2.47.3