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Date: Mon, 27 May 2024 15:16:55 +0200
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Subject: Re: [PATCH] tools/memory-model: Document herd7 (internal)
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To: Andrea Parri <parri.andrea@gmail.com>, stern@rowland.harvard.edu,
 will@kernel.org, peterz@infradead.org, boqun.feng@gmail.com,
 npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk,
 luc.maranget@inria.fr, paulmck@kernel.org, akiyks@gmail.com,
 dlustig@nvidia.com, joel@joelfernandes.org
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
 hernan.poncedeleon@huaweicloud.com
References: <20240524151356.236071-1-parri.andrea@gmail.com>
 <ZlC0IkzpQdeGj+a3@andrea>
From: Jonas Oberhauser <jonas.oberhauser@huaweicloud.com>
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Am 5/24/2024 um 5:37 PM schrieb Andrea Parri:
>> - While checking the information below using herd7, I've observed some
>>    "strange" behavior with spin_is_locked() (perhaps, unsurprisingly...);
>>    IAC, that's also excluded from this table/submission.
> 
> For completeness, the behavior in question:
> 
> $ cat T.litmus
> C T
> 
> {}
> 
> P0(spinlock_t *x)
> {
> 	int r0;
> 
> 	spin_lock(x);
> 	spin_unlock(x);
> 	r0 = spin_is_locked(x);
> }
> 

Since 0 executions are generated, possibly herd things there's a deadlock.

Could be either a problem with the deadlock definition, or do you need 
to initialize the lock somehow?