2021-02-19 17:31:39

by Lorenzo Bianconi

[permalink] [raw]
Subject: [PATCH v2 7/8] mt76: mt7921: fix uninitialized pointer access in mt7921_get_wtbl_info

From: Sean Wang <[email protected]>

fix possible uninitialized pointer access in mt7921_get_wtbl_info
routine

[ 270.073205] wlp1s0: deauthenticating from 9c:5c:8e:c9:93:14 by local choice (Reason: 3=DEAUTH_LEAVING)
[ 270.094918] 8<--- cut here ---
[ 270.097988] Unable to handle kernel NULL pointer dereference at virtual address 0000000a
[ 270.106120] pgd = 7ac68838
[ 270.108842] [0000000a] *pgd=00000000
[ 270.112426] Internal error: Oops: 805 [#1] SMP ARM
[ 270.117216] Modules linked in: mt7921e mt76_connac_lib mt76
[ 270.122803] CPU: 0 PID: 7 Comm: kworker/u8:0 Tainted: G W 5.11.0-rc2+ #67
[ 270.130891] Hardware name: Mediatek Cortex-A7 (Device Tree)
[ 270.136459] Workqueue: phy0 mt7921_mac_work [mt7921e]
[ 270.141557] PC is at mt7921_get_wtbl_info+0x224/0x2d8 [mt7921e]
[ 270.147498] LR is at 0x0
[ 270.150026] pc : [<bf030398>] lr : [<00000000>] psr: 60000013

...

[ 270.317696] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 270.325869] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[ 270.334043] [<bf030398>] (mt7921_get_wtbl_info [mt7921e]) from [<bf02ea9c>] (mt7921_mac_work+0x298/0x2c0 [mt7921e])
[ 270.344529] [<bf02ea9c>] (mt7921_mac_work [mt7921e]) from [<c013cde8>] (process_one_work+0x1f0/0x538)
[ 270.353780] [<c013cde8>] (process_one_work) from [<c013d17c>] (worker_thread+0x4c/0x55c)
[ 270.361874] [<c013d17c>] (worker_thread) from [<c01447a8>] (kthread+0x124/0x150)
[ 270.369275] [<c01447a8>] (kthread) from [<c0100150>] (ret_from_fork+0x14/0x24)
[ 270.376501] Exception stack(0xc19c7fb0 to 0xc19c7ff8)
[ 270.381550] 7fa0: 00000000 00000000 00000000 00000000
[ 270.389724] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 270.397896] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[ 270.404509] Code: e59de012 e1cdc1b6 e1cdc1b8 e59dc016 (e582e00a)

Fixes: 1c099ab44727c ("mt76: mt7921: add MCU support")
Signed-off-by: Sean Wang <[email protected]>
Signed-off-by: Lorenzo Bianconi <[email protected]>
---
drivers/net/wireless/mediatek/mt76/mt7921/mcu.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
index d784c75d47bf..58de7f32a625 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
@@ -404,11 +404,10 @@ mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb,

if (wlan_idx >= MT76_N_WCIDS)
return;
+
wcid = rcu_dereference(dev->mt76.wcid[wlan_idx]);
- if (!wcid) {
- stats->tx_rate = rate;
+ if (!wcid)
return;
- }

msta = container_of(wcid, struct mt7921_sta, wcid);
stats = &msta->stats;
--
2.29.2