[PATCH 5.19 003/192] wifi: mt76: mt7921e: fix crash in chip reset fail

Greg Kroah-Hartman
2022-09-13T14:09:34Z

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

commit fa3fbe64037839f448dc569212bafc5a495d8219 upstream.

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>

Cc: stable@vger.kernel.org
Fixes: 0efaf31dec57 ("mt76: mt7921: fix MT7921E reset failure")
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Link: https://lore.kernel.org/r/727eb5ffd3c7c805245e512da150ecf0a7154020.1659452909.git.deren.wu@mediatek.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/pci_mac.c
@@ -345,7 +345,7 @@ int mt7921e_mac_reset(struct mt7921_dev

err = mt7921e_driver_own(dev);
if (err)
- return err;
+ goto out;

err = mt7921_run_firmware(dev);
if (err)