Re: [PATCH mt76] wifi: mt76: mt7996: Do not run ieee80211_iter_keys() for scanning links in mt7996_vif_link_remove()

[Ben Greear <greearb@candelatech.com>]

On 11/17/25 11:11 AM, Lorenzo Bianconi wrote:
>> On 11/15/25 2:41 AM, Lorenzo Bianconi wrote:
>>> mt7996_vif_link_remove routine is executed by mt76_scan_complete()
>>> without holding the wiphy mutex triggering the following lockdep warning.
>>
>> Hello Lorenzo,
>>
>> Thank you for the patch.  This appears to fix the lockdep splats I was
>> seeing, and kernel is stable in at least initial testing.
> 
> thx Ben for testing the patch. Are you ok with adding your Tested-by tag?

Sure:

Tested-by: Ben Greear <greearb@candelatech.com>

Thanks,
Ben

> 
> Regards,
> Lorenzo
> 
>>
>> Thanks,
>> Ben
>>
>>>
>>>    WARNING: CPU: 0 PID: 72 at net/mac80211/key.c:1029 ieee80211_iter_keys+0xe4/0x1a0 [mac80211]
>>>    CPU: 0 UID: 0 PID: 72 Comm: kworker/u32:2 Tainted: G S                  6.18.0-rc5+ #27 PREEMPT(full)
>>>    Tainted: [S]=CPU_OUT_OF_SPEC
>>>    Hardware name: Default string Default string/SKYBAY, BIOS 5.12 02/15/2023
>>>    Workqueue: phy3 mt76_scan_work [mt76]
>>>    RIP: 0010:ieee80211_iter_keys+0xe4/0x1a0 [mac80211]
>>>    Code: 4c 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 8b 47 48 be ff ff ff ff 48 8d 78 68 e8 b4 eb 1e e1 85 c0 0f 85 49
>>> ff ff ff 4c 8b ab 90 1a 00 00 48 8d 83 90
>>>    RSP: 0018:ffffc900002f7cb0 EFLAGS: 00010246
>>>    RAX: 0000000000000000 RBX: ffff888127e00ee0 RCX: 0000000000000000
>>>    RDX: 0000000000000000 RSI: ffff888127e00788 RDI: ffff88811132b5c8
>>>    RBP: ffffffffa0ddf400 R08: 0000000000000001 R09: 000000009dcc1dac
>>>    R10: 0000000000000001 R11: ffff88811132b5a0 R12: ffffc900002f7d00
>>>    R13: ffff8882581e6a80 R14: ffff888127e0afc8 R15: ffff888158832038
>>>    FS:  0000000000000000(0000) GS:ffff8884da486000(0000) knlGS:0000000000000000
>>>    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>    CR2: 0000000030a0fd90 CR3: 0000000002c52004 CR4: 00000000003706f0
>>>    Call Trace:
>>>     <TASK>
>>>     ? lock_acquire+0xc2/0x2c0
>>>     mt7996_vif_link_remove+0x64/0x2b0 [mt7996e]
>>>     mt76_put_vif_phy_link+0x41/0x50 [mt76]
>>>     mt76_scan_complete+0x77/0x100 [mt76]
>>>     mt76_scan_work+0x2eb/0x3f0 [mt76]
>>>     ? process_one_work+0x1e5/0x6d0
>>>     process_one_work+0x221/0x6d0
>>>     worker_thread+0x19a/0x340
>>>     ? rescuer_thread+0x450/0x450
>>>     kthread+0x108/0x220
>>>     ? kthreads_online_cpu+0x110/0x110
>>>     ret_from_fork+0x1c6/0x220
>>>     ? kthreads_online_cpu+0x110/0x110
>>>     ret_from_fork_asm+0x11/0x20
>>>     </TASK>
>>>    irq event stamp: 45471
>>>    hardirqs last  enabled at (45477): [<ffffffff813d446e>] __up_console_sem+0x5e/0x70
>>>    hardirqs last disabled at (45482): [<ffffffff813d4453>] __up_console_sem+0x43/0x70
>>>    softirqs last  enabled at (44500): [<ffffffff81f2ae0c>] napi_pp_put_page+0xac/0xd0
>>>    softirqs last disabled at (44498): [<ffffffff81fa32a0>] page_pool_put_unrefed_netmem+0x290/0x3d0
>>>    ---[ end trace 0000000000000000 ]---
>>>
>>> Fix the issue skipping ieee80211_iter_keys() for scanning links in
>>> mt7996_vif_link_remove routine since we have not uploaded any hw keys
>>> for these links.
>>>
>>> Fixes: 04414d7bba78 ("wifi: mt76: mt7996: delete vif keys when requested")
>>> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
>>> ---
>>>    drivers/net/wireless/mediatek/mt76/mt7996/main.c | 3 ++-
>>>    1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
>>> index 2a45db398fd597180c0b2bfc12e019b514f24fd6..beed795edb24c67e1b7b44fe87fd5de125a21d94 100644
>>> --- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
>>> +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
>>> @@ -392,7 +392,8 @@ void mt7996_vif_link_remove(struct mt76_phy *mphy, struct ieee80211_vif *vif,
>>>    	};
>>>    	int idx = msta_link->wcid.idx;
>>> -	ieee80211_iter_keys(mphy->hw, vif, mt7996_key_iter, &it);
>>> +	if (!mlink->wcid->offchannel)
>>> +		ieee80211_iter_keys(mphy->hw, vif, mt7996_key_iter, &it);
>>>    	mt7996_mcu_add_sta(dev, link_conf, NULL, link, NULL,
>>>    			   CONN_STATE_DISCONNECT, false);
>>>
>>> ---
>>> base-commit: 09600421ffe2acc1a00ec466b25485f11b6bb957
>>> change-id: 20251115-mt7996-key-iter-link-remove-fix-7cf4d529c5a0
>>>
>>> Best regards,
>>
>>
>> -- 
>> Ben Greear <greearb@candelatech.com>
>> Candela Technologies Inc  http://www.candelatech.com


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com