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

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Message-ID: <716d189d-1f62-4fc0-9bb5-6c78967c5cba@ti.com>
Date: Thu, 22 Aug 2024 10:52:40 +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 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?

>
> 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);