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

[Lorenzo Bianconi <lorenzo@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 4273 bytes --]

> 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?

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

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]