Subject: Re: [PATCH] ipc/sem: do not sleep with a spin lock held
From:   Vasily Averin <vvs@virtuozzo.com>
To:     Manfred Spraul <manfred@colorfullife.com>, cgel.zte@gmail.com,
        akpm@linux-foundation.org
Cc:     shakeelb@google.com, rdunlap@infradead.org, dbueso@suse.de,
        unixbhaskar@gmail.com, chi.minghao@zte.com.cn, arnd@arndb.de,
        linux-kernel@vger.kernel.org, Zeal Robot <zealci@zte.com.cn>
References: <20211222081026.484058-1-chi.minghao@zte.com.cn>
 <63840bf3-2199-3240-bdfa-abb55518b5f9@colorfullife.com>
 <1181e64b-94c0-908a-b9e9-1a38f4610430@virtuozzo.com>
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Date:   Wed, 22 Dec 2021 18:50:58 +0300
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On 22.12.2021 18:31, Vasily Averin wrote:
> On 22.12.2021 14:45, Manfred Spraul wrote:
>> Hi Minghao,
>>
>> On 12/22/21 09:10, cgel.zte@gmail.com wrote:
>>> From: Minghao Chi <chi.minghao@zte.com.cn>
>>>
>>> We can't call kvfree() with a spin lock held, so defer it.
> 
> I'm sorry, but I do not understand why exactly we cannot use kvfree?
> Could you explain it in more details?

Got it,
there is cond_resched() called in __vfree() -> __vunmap()

However I'm still not sure that in_interrupt() is used correctly here.

Thank you,
	Vasily Averin