linux-kernel - Re: [PATCH 1/2] optee: fix tee out of memory failure seen during kexec reboot

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Message-ID: <cbc963d5-6c4b-7e69-4a9b-3d66b95affab@linux.microsoft.com>
Date:   Tue, 23 Feb 2021 21:56:13 +0530
From:   Allen Pais <apais@...ux.microsoft.com>
To:     Jens Wiklander <jens.wiklander@...aro.org>
Cc:     Dhananjay Phadke <dphadke@...ux.microsoft.com>,
        allen.lkml@...il.com, zajec5@...il.com,
        linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org,
        op-tee@...ts.trustedfirmware.org,
        linux-arm-kernel@...ts.infradead.org,
        bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH 1/2] optee: fix tee out of memory failure seen during
 kexec reboot



>>>> -	/*
>>>> -	 * Ask OP-TEE to free all cached shared memory objects to decrease
>>>> -	 * reference counters and also avoid wild pointers in secure world
>>>> -	 * into the old shared memory range.
>>>> -	 */
>>>> -	optee_disable_shm_cache(optee);
>>>> +	if (shutdown) {
>>>> +		optee_disable_shm_cache(optee);
>>>> +	} else {
>>>> +		/*
>>>> +		 * Ask OP-TEE to free all cached shared memory
>>>> +		 * objects to decrease reference counters and
>>>> +		 * also avoid wild pointers in secure world
>>>> +		 * into the old shared memory range.
>>>> +		 */
>>>> +		optee_disable_shm_cache(optee);
>>> Calling optee_disable_shm_cache() in both if and else. It could be
>>> put in front of if().
>>>
>>
>>    Ideally, I could just use optee_remove for shutdown() too.
>> But it would not look good. Hence this approach.
> 
> What is the problem with using optee_remove() for shutdown()?
> 

  There is no problem, I just thought it would be more cleaner/readable
with this approach. If you'd like to keep it simple by just calling
optee_remove() for shutdown() too, I could quickly send out V2.

Thanks for the review.

- Allen