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Date: Mon, 8 Jan 2024 08:28:46 -0800
From: Boqun Feng <boqun.feng@gmail.com>
To: Xuewen Yan <xuewen.yan94@gmail.com>
Cc: Xuewen Yan <xuewen.yan@unisoc.com>, peterz@infradead.org,
	mingo@redhat.com, will@kernel.org, longman@redhat.com,
	ke.wang@unisoc.com, zhiguo.niu@unisoc.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lock/lockdep: Add missing graph_unlock in validate_chain
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References: <20240104054030.14733-1-xuewen.yan@unisoc.com>
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On Fri, Jan 05, 2024 at 12:46:36PM +0800, Xuewen Yan wrote:
[...]
> >
> > Are you hitting a real issue or this is found by code reading?
> 
> Indeed, we hit a real issue:
> One cpu did not call graph_unlock, as a result, caused a deadlock with
> other cpus,
> because any cpu calling raw_spin_lock would get the graph_lock first.
> 

Could you share more details about the real issue you hit? For example,
serial log? I asked because although the graph_unlock() makes logical
sense, but that path should really not hit if lockdep works correctly.
Thanks!

Regards,
Boqun

> Thanks!