netdev - Re: [syzbot] [kasan?] [mm?] INFO: rcu detected stall in __run_timer

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Message-Id: <20240507033242.1616594-1-luyun@kylinos.cn>
Date: Tue,  7 May 2024 11:32:42 +0800
From: Yun Lu <luyun@...inos.cn>
To: hdanton@...a.com
Cc: linux-kernel@...r.kernel.org,
	syzbot+1acbadd9f48eeeacda29@...kaller.appspotmail.com,
	syzkaller-bugs@...glegroups.com,
	vinicius.gomes@...el.com,
	jhs@...atatu.com,
	netdev@...r.kernel.org
Subject: Re: [syzbot] [kasan?] [mm?] INFO: rcu detected stall in __run_timer_base

Hello,

Indeed, the taprio hrtimer does cause CPU stuck in certain specific scenarios,
and this patch indirectly confirms it.

However, it seems this patch isn't the final solution? 

On my testing machine, after starting Taprio hrtimer and then adjusting the
system time backward, it can be observed that the taprio hrtimer indeed gets stuck
in an infinite loop through tracing. And, the patch below can effectively resolve
this issue, but it doesn't work for syzbot's tests.

https://lore.kernel.org/all/20240506023617.1309937-1-luyun@kylinos.cn/

Are there any better suggestions from others regarding the resolution of this CPU stuck issue?