* [PATCH -next] i3c: master: svc: drop free_irq of devm_request_irq allocated irq
@ 2021-05-18 13:11 Yang Yingliang
2021-05-27 10:01 ` Miquel Raynal
0 siblings, 1 reply; 5+ messages in thread
From: Yang Yingliang @ 2021-05-18 13:11 UTC (permalink / raw)
To: linux-kernel, linux-i3c; +Cc: alexandre.belloni
irq allocated with devm_request_irq should not be freed using
free_irq, because doing so causes a dangling pointer, and a
subsequent double free.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
drivers/i3c/master/svc-i3c-master.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 1f6ba4221817..761c9c468357 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1448,7 +1448,7 @@ static int svc_i3c_master_remove(struct platform_device *pdev)
if (ret)
return ret;
- free_irq(master->irq, master);
+ devm_free_irq(&pdev->dev, master->irq, master);
clk_disable_unprepare(master->pclk);
clk_disable_unprepare(master->fclk);
clk_disable_unprepare(master->sclk);
--
2.25.1
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH -next] i3c: master: svc: drop free_irq of devm_request_irq allocated irq
2021-05-18 13:11 [PATCH -next] i3c: master: svc: drop free_irq of devm_request_irq allocated irq Yang Yingliang
@ 2021-05-27 10:01 ` Miquel Raynal
2021-05-27 13:49 ` Yang Yingliang
0 siblings, 1 reply; 5+ messages in thread
From: Miquel Raynal @ 2021-05-27 10:01 UTC (permalink / raw)
To: Yang Yingliang; +Cc: linux-kernel, linux-i3c, alexandre.belloni
Hi Yang,
Yang Yingliang <yangyingliang@huawei.com> wrote on Tue, 18 May 2021
21:11:27 +0800:
> irq allocated with devm_request_irq should not be freed using
> free_irq, because doing so causes a dangling pointer, and a
> subsequent double free.
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> drivers/i3c/master/svc-i3c-master.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index 1f6ba4221817..761c9c468357 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -1448,7 +1448,7 @@ static int svc_i3c_master_remove(struct platform_device *pdev)
> if (ret)
> return ret;
>
> - free_irq(master->irq, master);
> + devm_free_irq(&pdev->dev, master->irq, master);
Wouldn't removing this call the right solution? If it's a device
managed resource, it won't probably be needed to free it explicitly in
the remove path.
> clk_disable_unprepare(master->pclk);
> clk_disable_unprepare(master->fclk);
> clk_disable_unprepare(master->sclk);
Thanks,
Miquèl
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH -next] i3c: master: svc: drop free_irq of devm_request_irq allocated irq
2021-05-27 10:01 ` Miquel Raynal
@ 2021-05-27 13:49 ` Yang Yingliang
2021-05-27 14:40 ` Miquel Raynal
0 siblings, 1 reply; 5+ messages in thread
From: Yang Yingliang @ 2021-05-27 13:49 UTC (permalink / raw)
To: Miquel Raynal; +Cc: linux-kernel, linux-i3c, alexandre.belloni
Hi,
On 2021/5/27 18:01, Miquel Raynal wrote:
> Hi Yang,
>
> Yang Yingliang <yangyingliang@huawei.com> wrote on Tue, 18 May 2021
> 21:11:27 +0800:
>
>> irq allocated with devm_request_irq should not be freed using
>> free_irq, because doing so causes a dangling pointer, and a
>> subsequent double free.
>>
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>> drivers/i3c/master/svc-i3c-master.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
>> index 1f6ba4221817..761c9c468357 100644
>> --- a/drivers/i3c/master/svc-i3c-master.c
>> +++ b/drivers/i3c/master/svc-i3c-master.c
>> @@ -1448,7 +1448,7 @@ static int svc_i3c_master_remove(struct platform_device *pdev)
>> if (ret)
>> return ret;
>>
>> - free_irq(master->irq, master);
>> + devm_free_irq(&pdev->dev, master->irq, master);
> Wouldn't removing this call the right solution? If it's a device
> managed resource, it won't probably be needed to free it explicitly in
> the remove path.
Some drivers would expect to free irq itself, I am not sure if it's ok
to remove
the free_irq() in i3c, I just keep the original logic here and avoid
double free.
Thanks,
Yang
>
>> clk_disable_unprepare(master->pclk);
>> clk_disable_unprepare(master->fclk);
>> clk_disable_unprepare(master->sclk);
> Thanks,
> Miquèl
> .
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH -next] i3c: master: svc: drop free_irq of devm_request_irq allocated irq
2021-05-27 13:49 ` Yang Yingliang
@ 2021-05-27 14:40 ` Miquel Raynal
2021-05-28 1:43 ` Yang Yingliang
0 siblings, 1 reply; 5+ messages in thread
From: Miquel Raynal @ 2021-05-27 14:40 UTC (permalink / raw)
To: Yang Yingliang; +Cc: linux-kernel, linux-i3c, alexandre.belloni
Hi Yang,
Yang Yingliang <yangyingliang@huawei.com> wrote on Thu, 27 May 2021
21:49:53 +0800:
> Hi,
>
> On 2021/5/27 18:01, Miquel Raynal wrote:
> > Hi Yang,
> >
> > Yang Yingliang <yangyingliang@huawei.com> wrote on Tue, 18 May 2021
> > 21:11:27 +0800:
> >
> >> irq allocated with devm_request_irq should not be freed using
> >> free_irq, because doing so causes a dangling pointer, and a
> >> subsequent double free.
> >>
> >> Reported-by: Hulk Robot <hulkci@huawei.com>
> >> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> >> ---
> >> drivers/i3c/master/svc-i3c-master.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> >> index 1f6ba4221817..761c9c468357 100644
> >> --- a/drivers/i3c/master/svc-i3c-master.c
> >> +++ b/drivers/i3c/master/svc-i3c-master.c
> >> @@ -1448,7 +1448,7 @@ static int svc_i3c_master_remove(struct platform_device *pdev)
> >> if (ret)
> >> return ret;
> >> >> - free_irq(master->irq, master);
> >> + devm_free_irq(&pdev->dev, master->irq, master);
> > Wouldn't removing this call the right solution? If it's a device
> > managed resource, it won't probably be needed to free it explicitly in
> > the remove path.
> Some drivers would expect to free irq itself,
I don't get it. Drivers do not expect anything, they should just comply
with the API. If robots complain because a device managed resource is
being freed without the device managed helper, this does not mean that
the resource should explicitly be freed, it just means that *if* it
must be explicitly freed, the wrong helper is being used.
> I am not sure if it's ok to remove the free_irq() in i3c,
What is the link with I3C? Sorry I might be missing something but
master->irq is a driver variable, I don't get the link with the I3C
framework and why it would interfere.
> I just keep the original logic here and avoid double free.
I don't think it is sane. Calling devm_free_irq() maybe is the right
solution - I don't feel like it is - but your certainly can't hide
behind a 'I just want the robots to be happy' justification. Hiding
bugs on purpose is not something that I personally appreciate much.
Thanks,
Miquèl
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH -next] i3c: master: svc: drop free_irq of devm_request_irq allocated irq
2021-05-27 14:40 ` Miquel Raynal
@ 2021-05-28 1:43 ` Yang Yingliang
0 siblings, 0 replies; 5+ messages in thread
From: Yang Yingliang @ 2021-05-28 1:43 UTC (permalink / raw)
To: Miquel Raynal; +Cc: linux-kernel, linux-i3c, alexandre.belloni
On 2021/5/27 22:40, Miquel Raynal wrote:
> Hi Yang,
>
> Yang Yingliang <yangyingliang@huawei.com> wrote on Thu, 27 May 2021
> 21:49:53 +0800:
>
>> Hi,
>>
>> On 2021/5/27 18:01, Miquel Raynal wrote:
>>> Hi Yang,
>>>
>>> Yang Yingliang <yangyingliang@huawei.com> wrote on Tue, 18 May 2021
>>> 21:11:27 +0800:
>>>
>>>> irq allocated with devm_request_irq should not be freed using
>>>> free_irq, because doing so causes a dangling pointer, and a
>>>> subsequent double free.
>>>>
>>>> Reported-by: Hulk Robot <hulkci@huawei.com>
>>>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>>>> ---
>>>> drivers/i3c/master/svc-i3c-master.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
>>>> index 1f6ba4221817..761c9c468357 100644
>>>> --- a/drivers/i3c/master/svc-i3c-master.c
>>>> +++ b/drivers/i3c/master/svc-i3c-master.c
>>>> @@ -1448,7 +1448,7 @@ static int svc_i3c_master_remove(struct platform_device *pdev)
>>>> if (ret)
>>>> return ret;
>>>> >> - free_irq(master->irq, master);
>>>> + devm_free_irq(&pdev->dev, master->irq, master);
>>> Wouldn't removing this call the right solution? If it's a device
>>> managed resource, it won't probably be needed to free it explicitly in
>>> the remove path.
>> Some drivers would expect to free irq itself,
> I don't get it. Drivers do not expect anything, they should just comply
> with the API. If robots complain because a device managed resource is
> being freed without the device managed helper, this does not mean that
> the resource should explicitly be freed, it just means that *if* it
> must be explicitly freed, the wrong helper is being used.
>
>> I am not sure if it's ok to remove the free_irq() in i3c,
> What is the link with I3C? Sorry I might be missing something but
> master->irq is a driver variable, I don't get the link with the I3C
> framework and why it would interfere.
>
>> I just keep the original logic here and avoid double free.
> I don't think it is sane. Calling devm_free_irq() maybe is the right
> solution - I don't feel like it is - but your certainly can't hide
> behind a 'I just want the robots to be happy' justification. Hiding
> bugs on purpose is not something that I personally appreciate much.
Freeing irq in ->remove() is earlier than in device manage framework, if
just remove the free_irq() in svc_i3c_master_remove() and free the irq by
device manage framework, I am not sure if it breaks the resource free
sequence in Silvaco I3C master driver. If it's OK, I can resend a patch with
removing the free_irq().
Thanks,
Yang
>
> Thanks,
> Miquèl
> .
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^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-05-18 13:11 [PATCH -next] i3c: master: svc: drop free_irq of devm_request_irq allocated irq Yang Yingliang
2021-05-27 10:01 ` Miquel Raynal
2021-05-27 13:49 ` Yang Yingliang
2021-05-27 14:40 ` Miquel Raynal
2021-05-28 1:43 ` Yang Yingliang
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