[PATCH 6.18 222/752] wifi: rtw88: Fix inadvertent sharing of struct ieee80211_supported_band data

Sasha Levin
2026-02-28T17:51:16Z

From: Bitterblue Smith <rtl8821cerfe2@gmail.com>

[ Upstream commit fcac0f23d4d20b11014a39f8e2527cdc12ec9c82 ]

Internally wiphy writes to individual channels in this structure,
so we must not share one static definition of channel list between
multiple device instances, because that causes hard to debug
breakage.

For example, with two rtw88 driven devices in the system, channel
information may get incoherent, preventing channel use.

Copied from commit 0ae36391c804 ("wifi: rtw89: Fix inadverent sharing
of struct ieee80211_supported_band data").

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/e94ad653-2b6d-4284-a33c-8c694f88955b@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/realtek/rtw88/main.c | 34 +++++++++++++++++++----
1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/main.c b/drivers/net/wireless/realtek/rtw88/main.c
index 6f35357e73246..dde2ea6a00e06 100644
--- a/drivers/net/wireless/realtek/rtw88/main.c
+++ b/drivers/net/wireless/realtek/rtw88/main.c
@@ -1658,16 +1658,41 @@ static u16 rtw_get_max_scan_ie_len(struct rtw_dev *rtwdev)
return len;
}

+static struct ieee80211_supported_band *
+rtw_sband_dup(struct rtw_dev *rtwdev,
+ const struct ieee80211_supported_band *sband)
+{
+ struct ieee80211_supported_band *dup;
+
+ dup = devm_kmemdup(rtwdev->dev, sband, sizeof(*sband), GFP_KERNEL);
+ if (!dup)
+ return NULL;
+
+ dup->channels = devm_kmemdup_array(rtwdev->dev, sband->channels,
+ sband->n_channels,
+ sizeof(*sband->channels),
+ GFP_KERNEL);
+ if (!dup->channels)
+ return NULL;
+
+ dup->bitrates = devm_kmemdup_array(rtwdev->dev, sband->bitrates,
+ sband->n_bitrates,
+ sizeof(*sband->bitrates),
+ GFP_KERNEL);
+ if (!dup->bitrates)
+ return NULL;
+
+ return dup;
+}
+
static void rtw_set_supported_band(struct ieee80211_hw *hw,
const struct rtw_chip_info *chip)
{
struct ieee80211_supported_band *sband;
struct rtw_dev *rtwdev = hw->priv;
- struct device *dev = rtwdev->dev;

if (chip->band & RTW_BAND_2G) {
- sband = devm_kmemdup(dev, &rtw_band_2ghz, sizeof(*sband),
- GFP_KERNEL);
+ sband = rtw_sband_dup(rtwdev, &rtw_band_2ghz);
if (!sband)
goto err_out;
if (chip->ht_supported)
@@ -1676,8 +1701,7 @@ static void rtw_set_supported_band(struct ieee80211_hw *hw,
}

if (chip->band & RTW_BAND_5G) {
- sband = devm_kmemdup(dev, &rtw_band_5ghz, sizeof(*sband),
- GFP_KERNEL);
+ sband = rtw_sband_dup(rtwdev, &rtw_band_5ghz);
if (!sband)
goto err_out;
if (chip->ht_supported)
--
2.51.0