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From: Baochen Qiang <quic_bqiang@quicinc.com>
To: <ath11k@lists.infradead.org>
CC: <linux-wireless@vger.kernel.org>, <quic_bqiang@quicinc.com>
Subject: [PATCH] wifi: ath11k: initialize rx_mcs_80 and rx_mcs_160 before use
Date: Fri, 2 Feb 2024 10:35:47 +0800
Message-ID: <20240202023547.11141-1-quic_bqiang@quicinc.com>
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Currently in ath11k_peer_assoc_h_he() rx_mcs_80 and rx_mcs_160
are used to calculate max_nss, see
	if (support_160)
		max_nss = min(rx_mcs_80, rx_mcs_160);
	else
		max_nss = rx_mcs_80;

Kernel test robot complains on uninitialized symbols:
drivers/net/wireless/ath/ath11k/mac.c:2321 ath11k_peer_assoc_h_he() error: uninitialized symbol 'rx_mcs_80'.
drivers/net/wireless/ath/ath11k/mac.c:2321 ath11k_peer_assoc_h_he() error: uninitialized symbol 'rx_mcs_160'.
drivers/net/wireless/ath/ath11k/mac.c:2323 ath11k_peer_assoc_h_he() error: uninitialized symbol 'rx_mcs_80'.

This is because there are some code paths that never set them, so
the assignment of max_nss can come from uninitialized variables.
This could result in some unknown issues since a wrong peer_nss
might be passed to firmware.

Change to initialize them to an invalid value at the beginning. This
makes sense because even max_nss gets an invalid value, due to either
or both of them being invalid, we can get an valid peer_nss with
following guard:
	arg->peer_nss = min(sta->deflink.rx_nss, max_nss)

Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.23

Fixes: 3db26ecf7114 ("ath11k: calculate the correct NSS of peer for HE capabilities")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202401311243.NyXwWZxP-lkp@intel.com/
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
---
 drivers/net/wireless/ath/ath11k/mac.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index bbf4d1f4d310..299f4f3d7659 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -2294,6 +2294,8 @@ static void ath11k_peer_assoc_h_he(struct ath11k *ar,
 	mcs_160_map = le16_to_cpu(he_cap->he_mcs_nss_supp.rx_mcs_160);
 	mcs_80_map = le16_to_cpu(he_cap->he_mcs_nss_supp.rx_mcs_80);
 
+	/* Initialize rx_mcs_160 to 9 which is an invalid value */
+	rx_mcs_160 = 9;
 	if (support_160) {
 		for (i = 7; i >= 0; i--) {
 			u8 mcs_160 = (mcs_160_map >> (2 * i)) & 3;
@@ -2305,6 +2307,8 @@ static void ath11k_peer_assoc_h_he(struct ath11k *ar,
 		}
 	}
 
+	/* Initialize rx_mcs_80 to 9 which is an invalid value */
+	rx_mcs_80 = 9;
 	for (i = 7; i >= 0; i--) {
 		u8 mcs_80 = (mcs_80_map >> (2 * i)) & 3;
 

base-commit: d4d13947306ab3c98c84389d9397563b550b71b8
-- 
2.25.1