netdev - Re: [PATCH] can: j1939: prevent deadlock by changing j1939_socks

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Message-ID: <20230705043955.GE15522@pengutronix.de>
Date: Wed, 5 Jul 2023 06:39:55 +0200
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Astra Joan <astrajoan@...oo.com>
Cc: davem@...emloft.net, edumazet@...gle.com, ivan.orlov0322@...il.com,
	kernel@...gutronix.de, kuba@...nel.org, linux-can@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux@...pel-privat.de,
	mkl@...gutronix.de, netdev@...r.kernel.org, pabeni@...hat.com,
	robin@...tonic.nl, skhan@...uxfoundation.org,
	socketcan@...tkopp.net,
	syzbot+1591462f226d9cbf0564@...kaller.appspotmail.com,
	syzkaller-bugs@...glegroups.com
Subject: Re: [PATCH] can: j1939: prevent deadlock by changing
 j1939_socks_lock to rwlock

On Tue, Jul 04, 2023 at 10:55:47AM -0700, Astra Joan wrote:
> Hi Oleksij,
> 
> Thank you for providing help with the bug fix! The patch was created
> when I was working on another bug:
> 
> https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84
> 
> But the patch was not a direct fix of the problem reported in the
> unregister_netdevice function call. Instead, it suppresses potential
> deadlock information to guarantee the real bug would show up. Since I
> have verified that the patch resolved a deadlock situation involving
> the exact same locks, I'm pretty confident it would be a proper fix for
> the current bug in this thread.
> 
> I'm not sure, though, about how I could instruct Syzbot to create a
> reproducer to properly test this patch. Could you or anyone here help
> me find the next step? Thank you so much!

Sorry, I'm not syzbot expert. I hope someone else can help here.

Regards,
Oleksij
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