RE: [PATCH v3 0/8] rtw88: prepare locking for SDIO support

[Pkshih]

> -----Original Message-----
> From: Pkshih
> Sent: Wednesday, January 19, 2022 5:38 PM
> To: 'Martin Blumenstingl' <martin.blumenstingl@xxxxxxxxxxxxxx>; linux-wireless@xxxxxxxxxxxxxxx
> Cc: tony0620emma@xxxxxxxxx; kvalo@xxxxxxxxxxxxxx; johannes@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; Neo Jou <neojou@xxxxxxxxx>; Jernej Skrabec <jernej.skrabec@xxxxxxxxx>; Ed
> Swierk <eswierk@xxxxx>
> Subject: RE: [PATCH v3 0/8] rtw88: prepare locking for SDIO support
> 
> Hi,
> 
> > -----Original Message-----
> > From: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
> > Sent: Saturday, January 8, 2022 8:55 AM
> > To: linux-wireless@xxxxxxxxxxxxxxx
> > Cc: tony0620emma@xxxxxxxxx; kvalo@xxxxxxxxxxxxxx; johannes@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> > linux-kernel@xxxxxxxxxxxxxxx; Neo Jou <neojou@xxxxxxxxx>; Jernej Skrabec <jernej.skrabec@xxxxxxxxx>;
> > Pkshih <pkshih@xxxxxxxxxxx>; Ed Swierk <eswierk@xxxxx>; Martin Blumenstingl
> > <martin.blumenstingl@xxxxxxxxxxxxxx>
> > Subject: [PATCH v3 0/8] rtw88: prepare locking for SDIO support
> >
> 
> [...]
> 
> I do stressed test of connection and suspend, and it get stuck after about
> 4 hours but no useful messages. I will re-build my kernel and turn on lockdep debug
> to see if it can tell me what is wrong.
> 

I found some deadlock: 

[ 4891.169653]        CPU0                    CPU1
[ 4891.169732]        ----                    ----
[ 4891.169799]   lock(&rtwdev->mutex);
[ 4891.169874]                                lock(&local->sta_mtx);
[ 4891.169948]                                lock(&rtwdev->mutex);
[ 4891.170050]   lock(&local->sta_mtx);


[ 4919.598630]        CPU0                    CPU1
[ 4919.598715]        ----                    ----
[ 4919.598779]   lock(&local->iflist_mtx);
[ 4919.598900]                                lock(&rtwdev->mutex);
[ 4919.598995]                                lock(&local->iflist_mtx);
[ 4919.599092]   lock(&rtwdev->mutex);

So, I add wrappers to iterate rtw_iterate_stas() and rtw_iterate_vifs() that
use _atomic version to collect sta and vif, and use list_for_each() to iterate.
Reference code is attached, and I'm still thinking if we can have better method.

--
Ping-Ke

Attachment: 0001-rtw88-use-atomic-to-collect-stas-and-does-iterators.patch
Description: 0001-rtw88-use-atomic-to-collect-stas-and-does-iterators.patch