linux-kernel - Re: [PATCH] remoteproc: k3-r5: Fix error handling when power-up failed

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Message-ID: <94faa49d-3acc-45c5-aa17-817e3fb31b5b@ti.com>
Date: Thu, 22 Aug 2024 11:12:36 +0530
From: Beleswar Prasad Padhi <b-padhi@...com>
To: Jan Kiszka <jan.kiszka@...mens.com>,
        Bjorn Andersson
	<andersson@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        <linux-remoteproc@...r.kernel.org>
CC: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Apurva Nandan
	<a-nandan@...com>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Nishanth Menon <nm@...com>
Subject: Re: [PATCH] remoteproc: k3-r5: Fix error handling when power-up
 failed


On 22-08-2024 10:57, Jan Kiszka wrote:
> On 22.08.24 07:22, Beleswar Prasad Padhi wrote:
>> On 21-08-2024 23:40, Jan Kiszka wrote:
>>> On 21.08.24 07:30, Beleswar Prasad Padhi wrote:
>>>> On 19-08-2024 20:54, Jan Kiszka wrote:
>>>>> From: Jan Kiszka <jan.kiszka@...mens.com>
>>>>>
>>>>> By simply bailing out, the driver was violating its rule and internal
>>>> Using device lifecycle managed functions to register the rproc
>>>> (devm_rproc_add()), bailing out with an error code will work.
>>>>
>>>>> assumptions that either both or no rproc should be initialized. E.g.,
>>>>> this could cause the first core to be available but not the second one,
>>>>> leading to crashes on its shutdown later on while trying to dereference
>>>>> that second instance.
>>>>>
>>>>> Fixes: 61f6f68447ab ("remoteproc: k3-r5: Wait for core0 power-up
>>>>> before powering up core1")
>>>>> Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
>>>>> ---
>>>>>     drivers/remoteproc/ti_k3_r5_remoteproc.c | 3 ++-
>>>>>     1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>>>>> b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>>>>> index 39a47540c590..eb09d2e9b32a 100644
>>>>> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>>>>> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>>>>> @@ -1332,7 +1332,7 @@ static int k3_r5_cluster_rproc_init(struct
>>>>> platform_device *pdev)
>>>>>                 dev_err(dev,
>>>>>                     "Timed out waiting for %s core to power up!\n",
>>>>>                     rproc->name);
>>>>> -            return ret;
>>>>> +            goto err_powerup;
>>>>>             }
>>>>>         }
>>>>>     @@ -1348,6 +1348,7 @@ static int k3_r5_cluster_rproc_init(struct
>>>>> platform_device *pdev)
>>>>>             }
>>>>>         }
>>>>>     +err_powerup:
>>>>>         rproc_del(rproc);
>>>> Please use devm_rproc_add() to avoid having to do rproc_del() manually
>>>> here.
>>> This is just be the tip of the iceberg. The whole code needs to be
>>> reworked accordingly so that we can drop these goto, not just this one.
>>
>> You are correct. Unfortunately, the organic growth of this driver has
>> resulted in a need to refactor. I plan on doing this and post the
>> refactoring soon. This should be part of the overall refactoring as
>> suggested by Mathieu[2]. But for the immediate problem, your fix does
>> patch things up.. hence:
>>
>> Acked-by: Beleswar Padhi <b-padhi@...com>
>>
>> [2]: https://lore.kernel.org/all/Zr4w8Vj0mVo5sBsJ@p14s/
>>
>>> Just look at k3_r5_reserved_mem_init. Your change in [1] was also too
>>> early in this regard, breaking current error handling additionally.
>>
>>
>> Curious, Could you point out how does the change in [1] breaks current
>> error handling?
>>
> Same story: You leave the inner loop of k3_r5_cluster_rproc_init() via
> return without that loop having been converted to support this.


The rproc has been allocated via devm_rproc_alloc[3] before the 
return[4] at k3_r5_cluster_rproc_init. Thus, it is capable of freeing 
the rproc just based on error codes. It was tested.
[3]: 
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/remoteproc/ti_k3_r5_remoteproc.c#n1238
[4]: 
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/remoteproc/ti_k3_r5_remoteproc.c#n1259

>
> Jan
>