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

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Message-ID: <3c8844db-0712-4727-a54c-0a156b3f9e9c@siemens.com>
Date: Wed, 21 Aug 2024 20:10:35 +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 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.
Just look at k3_r5_reserved_mem_init. Your change in [1] was also too
early in this regard, breaking current error handling additionally.

I'll stop my whac-a-mole. Someone needs to sit down and do that for the
complete code consistently. And test the error cases.

Jan

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=f3f11cfe890733373ddbb1ce8991ccd4ee5e79e1

> 
>>   err_add:
>>       k3_r5_reserved_mem_exit(kproc);

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