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From:   Deren Wu <Deren.Wu@mediatek.com>
To:     Felix Fietkau <nbd@nbd.name>, Lorenzo Bianconi <lorenzo@kernel.org>
CC:     Sean Wang <sean.wang@mediatek.com>,
        Soul Huang <Soul.Huang@mediatek.com>,
        YN Chen <YN.Chen@mediatek.com>,
        Leon Yen <Leon.Yen@mediatek.com>,
        "Eric-SY Chang" <Eric-SY.Chang@mediatek.com>,
        Deren Wu <Deren.Wu@mediatek.com>, KM Lin <km.lin@mediatek.com>,
        Robin Chiu <robin.chiu@mediatek.com>,
        CH Yeh <ch.yeh@mediatek.com>, Posh Sun <posh.sun@mediatek.com>,
        Stella Chang <Stella.Chang@mediatek.com>,
        Evelyn Tsai <evelyn.tsai@mediatek.com>,
        "Ryder Lee" <ryder.lee@mediatek.com>,
        Shayne Chen <shayne.chen@mediatek.com>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        linux-mediatek <linux-mediatek@lists.infradead.org>,
        Deren Wu <deren.wu@mediatek.com>
Subject: [PATCH] mt76: mt7921e: fix crash in chip reset fail
Date:   Tue, 2 Aug 2022 23:15:07 +0800
Message-ID: <727eb5ffd3c7c805245e512da150ecf0a7154020.1659452909.git.deren.wu@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

From: Deren Wu <deren.wu@mediatek.com>

In case of drv own fail in reset, we may need to run mac_reset several
times. The sequence would trigger system crash as the log below.

Because we do not re-enable/schedule "tx_napi" before disable it again,
the process would keep waiting for state change in napi_diable(). To
avoid the problem and keep status synchronize for each run, goto final
resource handling if drv own failed.

[ 5857.353423] mt7921e 0000:3b:00.0: driver own failed
[ 5858.433427] mt7921e 0000:3b:00.0: Timeout for driver own
[ 5859.633430] mt7921e 0000:3b:00.0: driver own failed
[ 5859.633444] ------------[ cut here ]------------
[ 5859.633446] WARNING: CPU: 6 at kernel/kthread.c:659 kthread_park+0x11d
[ 5859.633717] Workqueue: mt76 mt7921_mac_reset_work [mt7921_common]
[ 5859.633728] RIP: 0010:kthread_park+0x11d/0x150
[ 5859.633736] RSP: 0018:ffff8881b676fc68 EFLAGS: 00010202
......
[ 5859.633766] Call Trace:
[ 5859.633768]  <TASK>
[ 5859.633771]  mt7921e_mac_reset+0x176/0x6f0 [mt7921e]
[ 5859.633778]  mt7921_mac_reset_work+0x184/0x3a0 [mt7921_common]
[ 5859.633785]  ? mt7921_mac_set_timing+0x520/0x520 [mt7921_common]
[ 5859.633794]  ? __kasan_check_read+0x11/0x20
[ 5859.633802]  process_one_work+0x7ee/0x1320
[ 5859.633810]  worker_thread+0x53c/0x1240
[ 5859.633818]  kthread+0x2b8/0x370
[ 5859.633824]  ? process_one_work+0x1320/0x1320
[ 5859.633828]  ? kthread_complete_and_exit+0x30/0x30
[ 5859.633834]  ret_from_fork+0x1f/0x30
[ 5859.633842]  </TASK>

Fixes: 0efaf31dec57 ("mt76: mt7921: fix MT7921E reset failure")
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
---
 drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c
index e1800674089a..576a0149251b 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c
@@ -261,7 +261,7 @@ int mt7921e_mac_reset(struct mt7921_dev *dev)
 
 	err = mt7921e_driver_own(dev);
 	if (err)
-		return err;
+		goto out;
 
 	err = mt7921_run_firmware(dev);
 	if (err)
-- 
2.18.0