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

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Message-ID: <eaa07d0d-e2fc-49f2-8ee6-c18b5d7b3b5f@siemens.com>
Date: Thu, 22 Aug 2024 07:27:44 +0200
From: Jan Kiszka <jan.kiszka@...mens.com>
To: Beleswar Prasad Padhi <b-padhi@...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 22.08.24 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.

Jan

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