2021-10-28 05:53:27

by Yong Wu (吴勇)

[permalink] [raw]
Subject: [PATCH] memory: mtk-smi: Fix a null dereference for the ostd

We add the ostd setting for mt8195. It introduces a abort for the
previous SoC which doesn't have ostd setting. This is the log:

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000080
...
pc : mtk_smi_larb_config_port_gen2_general+0x64/0x130
lr : mtk_smi_larb_resume+0x54/0x98
...
Call trace:
mtk_smi_larb_config_port_gen2_general+0x64/0x130
pm_generic_runtime_resume+0x2c/0x48
__genpd_runtime_resume+0x30/0xa8
genpd_runtime_resume+0x94/0x2c8
__rpm_callback+0x44/0x150
rpm_callback+0x6c/0x78
rpm_resume+0x310/0x558
__pm_runtime_resume+0x3c/0x88

In the code: larbostd = larb->larb_gen->ostd[larb->larbid],
if "larb->larb_gen->ostd" is null, the "larbostd" is the offset, it is
also a valid value, thus, use the larb->larb_gen->ostd as the condition
inside the "for" loop.

Signed-off-by: Yong Wu <[email protected]>
---
Hi Krzysztof,
Could you help review and conside this as a fix for the mt8195 patchset?
The mt8195 patchset are not in mainline, thus, I don't know its sha-id,
and don't add Fixes tag.
Thanks
---
drivers/memory/mtk-smi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
index b883dcc0bbfa..0262a59a2d6e 100644
--- a/drivers/memory/mtk-smi.c
+++ b/drivers/memory/mtk-smi.c
@@ -257,7 +257,7 @@ static void mtk_smi_larb_config_port_gen2_general(struct device *dev)
if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_SW_FLAG))
writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base + SMI_LARB_SW_FLAG);

- for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd && !!larbostd[i]; i++)
+ for (i = 0; i < SMI_LARB_PORT_NR_MAX && larb->larb_gen->ostd && !!larbostd[i]; i++)
writel_relaxed(larbostd[i], larb->base + SMI_LARB_OSTDL_PORTx(i));

for_each_set_bit(i, (unsigned long *)larb->mmu, 32) {
--
2.18.0


2021-10-28 06:16:40

by Hsin-Yi Wang

[permalink] [raw]
Subject: Re: [PATCH] memory: mtk-smi: Fix a null dereference for the ostd

On Thu, Oct 28, 2021 at 1:51 PM Yong Wu <[email protected]> wrote:
>
> We add the ostd setting for mt8195. It introduces a abort for the
> previous SoC which doesn't have ostd setting. This is the log:
>
> Unable to handle kernel NULL pointer dereference at virtual address
> 0000000000000080
> ...
> pc : mtk_smi_larb_config_port_gen2_general+0x64/0x130
> lr : mtk_smi_larb_resume+0x54/0x98
> ...
> Call trace:
> mtk_smi_larb_config_port_gen2_general+0x64/0x130
> pm_generic_runtime_resume+0x2c/0x48
> __genpd_runtime_resume+0x30/0xa8
> genpd_runtime_resume+0x94/0x2c8
> __rpm_callback+0x44/0x150
> rpm_callback+0x6c/0x78
> rpm_resume+0x310/0x558
> __pm_runtime_resume+0x3c/0x88
>
> In the code: larbostd = larb->larb_gen->ostd[larb->larbid],
> if "larb->larb_gen->ostd" is null, the "larbostd" is the offset, it is
> also a valid value, thus, use the larb->larb_gen->ostd as the condition
> inside the "for" loop.
>
> Signed-off-by: Yong Wu <[email protected]>

Tested-by: Hsin-Yi Wang <[email protected]>

After applying this patch, mt8183 is no longer crashing.

> ---
> Hi Krzysztof,
> Could you help review and conside this as a fix for the mt8195 patchset?
> The mt8195 patchset are not in mainline, thus, I don't know its sha-id,
> and don't add Fixes tag.
> Thanks
> ---
> drivers/memory/mtk-smi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index b883dcc0bbfa..0262a59a2d6e 100644
> --- a/drivers/memory/mtk-smi.c
> +++ b/drivers/memory/mtk-smi.c
> @@ -257,7 +257,7 @@ static void mtk_smi_larb_config_port_gen2_general(struct device *dev)
> if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_SW_FLAG))
> writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base + SMI_LARB_SW_FLAG);
>
> - for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd && !!larbostd[i]; i++)
> + for (i = 0; i < SMI_LARB_PORT_NR_MAX && larb->larb_gen->ostd && !!larbostd[i]; i++)
> writel_relaxed(larbostd[i], larb->base + SMI_LARB_OSTDL_PORTx(i));
>
> for_each_set_bit(i, (unsigned long *)larb->mmu, 32) {
> --
> 2.18.0
>
>
> _______________________________________________
> Linux-mediatek mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-mediatek

2021-10-29 17:38:21

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH] memory: mtk-smi: Fix a null dereference for the ostd

On 28/10/2021 07:50, Yong Wu wrote:
> We add the ostd setting for mt8195. It introduces a abort for the
> previous SoC which doesn't have ostd setting. This is the log:
>
> Unable to handle kernel NULL pointer dereference at virtual address
> 0000000000000080
> ...
> pc : mtk_smi_larb_config_port_gen2_general+0x64/0x130
> lr : mtk_smi_larb_resume+0x54/0x98
> ...
> Call trace:
> mtk_smi_larb_config_port_gen2_general+0x64/0x130
> pm_generic_runtime_resume+0x2c/0x48
> __genpd_runtime_resume+0x30/0xa8
> genpd_runtime_resume+0x94/0x2c8
> __rpm_callback+0x44/0x150
> rpm_callback+0x6c/0x78
> rpm_resume+0x310/0x558
> __pm_runtime_resume+0x3c/0x88
>
> In the code: larbostd = larb->larb_gen->ostd[larb->larbid],
> if "larb->larb_gen->ostd" is null, the "larbostd" is the offset, it is
> also a valid value, thus, use the larb->larb_gen->ostd as the condition
> inside the "for" loop.

You need to write more clearly, what you are fixing here.

>
> Signed-off-by: Yong Wu <[email protected]>
> ---
> Hi Krzysztof,
> Could you help review and conside this as a fix for the mt8195 patchset?
> The mt8195 patchset are not in mainline, thus, I don't know its sha-id,
> and don't add Fixes tag.
> Thanks
> ---
> drivers/memory/mtk-smi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index b883dcc0bbfa..0262a59a2d6e 100644
> --- a/drivers/memory/mtk-smi.c
> +++ b/drivers/memory/mtk-smi.c
> @@ -257,7 +257,7 @@ static void mtk_smi_larb_config_port_gen2_general(struct device *dev)
> if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_SW_FLAG))
> writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base + SMI_LARB_SW_FLAG);
>
> - for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd && !!larbostd[i]; i++)
> + for (i = 0; i < SMI_LARB_PORT_NR_MAX && larb->larb_gen->ostd && !!larbostd[i]; i++)
> writel_relaxed(larbostd[i], larb->base + SMI_LARB_OSTDL_PORTx(i));

The code does not look good. You have already a dereference at line 244:

const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];

You are not fixing the NULL pointer dereference.

>
> for_each_set_bit(i, (unsigned long *)larb->mmu, 32) {
>


Best regards,
Krzysztof

2021-11-01 06:11:37

by Yong Wu (吴勇)

[permalink] [raw]
Subject: Re: [PATCH] memory: mtk-smi: Fix a null dereference for the ostd

On Fri, 2021-10-29 at 19:35 +0200, Krzysztof Kozlowski wrote:
> On 28/10/2021 07:50, Yong Wu wrote:
> > We add the ostd setting for mt8195. It introduces a abort for the
> > previous SoC which doesn't have ostd setting. This is the log:
> >
> > Unable to handle kernel NULL pointer dereference at virtual address
> > 0000000000000080
> > ...
> > pc : mtk_smi_larb_config_port_gen2_general+0x64/0x130
> > lr : mtk_smi_larb_resume+0x54/0x98
> > ...
> > Call trace:
> > mtk_smi_larb_config_port_gen2_general+0x64/0x130
> > pm_generic_runtime_resume+0x2c/0x48
> > __genpd_runtime_resume+0x30/0xa8
> > genpd_runtime_resume+0x94/0x2c8
> > __rpm_callback+0x44/0x150
> > rpm_callback+0x6c/0x78
> > rpm_resume+0x310/0x558
> > __pm_runtime_resume+0x3c/0x88
> >
> > In the code: larbostd = larb->larb_gen->ostd[larb->larbid],
> > if "larb->larb_gen->ostd" is null, the "larbostd" is the offset, it
> > is
> > also a valid value, thus, use the larb->larb_gen->ostd as the
> > condition
> > inside the "for" loop.
>
> You need to write more clearly, what you are fixing here.
>
> >
> > Signed-off-by: Yong Wu <[email protected]>
> > ---
> > Hi Krzysztof,
> > Could you help review and conside this as a fix for the mt8195
> > patchset?
> > The mt8195 patchset are not in mainline, thus, I don't know its
> > sha-id,
> > and don't add Fixes tag.
> > Thanks
> > ---
> > drivers/memory/mtk-smi.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> > index b883dcc0bbfa..0262a59a2d6e 100644
> > --- a/drivers/memory/mtk-smi.c
> > +++ b/drivers/memory/mtk-smi.c
> > @@ -257,7 +257,7 @@ static void
> > mtk_smi_larb_config_port_gen2_general(struct device *dev)
> > if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_SW_FLAG))
> > writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base +
> > SMI_LARB_SW_FLAG);
> >
> > - for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd &&
> > !!larbostd[i]; i++)
> > + for (i = 0; i < SMI_LARB_PORT_NR_MAX && larb->larb_gen->ostd &&
> > !!larbostd[i]; i++)
> > writel_relaxed(larbostd[i], larb->base +
> > SMI_LARB_OSTDL_PORTx(i));
>
> The code does not look good. You have already a dereference at line
> 244:
>
> const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];

if larb->larb_gen->ostd is null, larbostd is the offset, e.g. 0x80 in
the log above. thus, we can not use "larbostd[i]" in the "for" loop.

sorry for the unreadable. In this case, is the change ok?

or like this:

-const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];
+const u8 *larbostd = larb->larb_gen->ostd ? larb->larb_gen-ostd[larb-
>larbid] : NULL;

or add a explicit "if":
if (larb->larb_gen->ostd)
larbostd = xxx.

Which one do you prefer?

Thanks.

>
> You are not fixing the NULL pointer dereference.
>
> >
> > for_each_set_bit(i, (unsigned long *)larb->mmu, 32) {
> >
>
>
> Best regards,
> Krzysztof

2021-11-01 08:48:24

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH] memory: mtk-smi: Fix a null dereference for the ostd

On 01/11/2021 07:09, Yong Wu wrote:
> On Fri, 2021-10-29 at 19:35 +0200, Krzysztof Kozlowski wrote:
>> On 28/10/2021 07:50, Yong Wu wrote:
>>> We add the ostd setting for mt8195. It introduces a abort for the
>>> previous SoC which doesn't have ostd setting. This is the log:
>>>
>>> Unable to handle kernel NULL pointer dereference at virtual address
>>> 0000000000000080
>>> ...
>>> pc : mtk_smi_larb_config_port_gen2_general+0x64/0x130
>>> lr : mtk_smi_larb_resume+0x54/0x98
>>> ...
>>> Call trace:
>>> mtk_smi_larb_config_port_gen2_general+0x64/0x130
>>> pm_generic_runtime_resume+0x2c/0x48
>>> __genpd_runtime_resume+0x30/0xa8
>>> genpd_runtime_resume+0x94/0x2c8
>>> __rpm_callback+0x44/0x150
>>> rpm_callback+0x6c/0x78
>>> rpm_resume+0x310/0x558
>>> __pm_runtime_resume+0x3c/0x88
>>>
>>> In the code: larbostd = larb->larb_gen->ostd[larb->larbid],
>>> if "larb->larb_gen->ostd" is null, the "larbostd" is the offset, it
>>> is
>>> also a valid value, thus, use the larb->larb_gen->ostd as the
>>> condition
>>> inside the "for" loop.
>>
>> You need to write more clearly, what you are fixing here.
>>
>>>
>>> Signed-off-by: Yong Wu <[email protected]>
>>> ---
>>> Hi Krzysztof,
>>> Could you help review and conside this as a fix for the mt8195
>>> patchset?
>>> The mt8195 patchset are not in mainline, thus, I don't know its
>>> sha-id,
>>> and don't add Fixes tag.
>>> Thanks
>>> ---
>>> drivers/memory/mtk-smi.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
>>> index b883dcc0bbfa..0262a59a2d6e 100644
>>> --- a/drivers/memory/mtk-smi.c
>>> +++ b/drivers/memory/mtk-smi.c
>>> @@ -257,7 +257,7 @@ static void
>>> mtk_smi_larb_config_port_gen2_general(struct device *dev)
>>> if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_SW_FLAG))
>>> writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base +
>>> SMI_LARB_SW_FLAG);
>>>
>>> - for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd &&
>>> !!larbostd[i]; i++)
>>> + for (i = 0; i < SMI_LARB_PORT_NR_MAX && larb->larb_gen->ostd &&
>>> !!larbostd[i]; i++)
>>> writel_relaxed(larbostd[i], larb->base +
>>> SMI_LARB_OSTDL_PORTx(i));
>>
>> The code does not look good. You have already a dereference at line
>> 244:
>>
>> const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];
>
> if larb->larb_gen->ostd is null, larbostd is the offset, e.g. 0x80 in
> the log above. thus, we can not use "larbostd[i]" in the "for" loop.
>
> sorry for the unreadable. In this case, is the change ok?

No, it's ok, I did not check the type of ostd and it's confusing a bit
that it is defined as a pointer to an array but you actually use it as
array of pointers to 32-elemenet arrays... Anyway I was mistaken and
there will be indeed no dereference at the assignment, but for code
clarity I would still prefer to do the check earlier, so:

>
> or like this:
>
> -const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];
> +const u8 *larbostd = larb->larb_gen->ostd ? larb->larb_gen-ostd[larb-
>> larbid] : NULL;

Although I think now the proper type should be explicit.
mtk_smi_larb_mt8195_ostd is an 28-element array of
SMI_LARB_PORT_NR_MAX-element u8 arrays, therefore struct
mtk_smi_larb_gen should be:
const u8 (*ostd)[][SMI_LARB_PORT_NR_MAX];

Right?


Best regards,
Krzysztof

2021-11-01 10:43:08

by Yong Wu (吴勇)

[permalink] [raw]
Subject: Re: [PATCH] memory: mtk-smi: Fix a null dereference for the ostd

On Mon, 2021-11-01 at 09:45 +0100, Krzysztof Kozlowski wrote:
> On 01/11/2021 07:09, Yong Wu wrote:
> > On Fri, 2021-10-29 at 19:35 +0200, Krzysztof Kozlowski wrote:
> > > On 28/10/2021 07:50, Yong Wu wrote:
> > > > We add the ostd setting for mt8195. It introduces a abort for
> > > > the
> > > > previous SoC which doesn't have ostd setting. This is the log:
> > > >
> > > > Unable to handle kernel NULL pointer dereference at virtual
> > > > address
> > > > 0000000000000080
> > > > ...
> > > > pc : mtk_smi_larb_config_port_gen2_general+0x64/0x130
> > > > lr : mtk_smi_larb_resume+0x54/0x98
> > > > ...
> > > > Call trace:
> > > > mtk_smi_larb_config_port_gen2_general+0x64/0x130
> > > > pm_generic_runtime_resume+0x2c/0x48
> > > > __genpd_runtime_resume+0x30/0xa8
> > > > genpd_runtime_resume+0x94/0x2c8
> > > > __rpm_callback+0x44/0x150
> > > > rpm_callback+0x6c/0x78
> > > > rpm_resume+0x310/0x558
> > > > __pm_runtime_resume+0x3c/0x88
> > > >
> > > > In the code: larbostd = larb->larb_gen->ostd[larb->larbid],
> > > > if "larb->larb_gen->ostd" is null, the "larbostd" is the
> > > > offset, it
> > > > is
> > > > also a valid value, thus, use the larb->larb_gen->ostd as the
> > > > condition
> > > > inside the "for" loop.
> > >
> > > You need to write more clearly, what you are fixing here.
> > >
> > > >
> > > > Signed-off-by: Yong Wu <[email protected]>
> > > > ---
> > > > Hi Krzysztof,
> > > > Could you help review and conside this as a fix for the mt8195
> > > > patchset?
> > > > The mt8195 patchset are not in mainline, thus, I don't know its
> > > > sha-id,
> > > > and don't add Fixes tag.
> > > > Thanks
> > > > ---
> > > > drivers/memory/mtk-smi.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-
> > > > smi.c
> > > > index b883dcc0bbfa..0262a59a2d6e 100644
> > > > --- a/drivers/memory/mtk-smi.c
> > > > +++ b/drivers/memory/mtk-smi.c
> > > > @@ -257,7 +257,7 @@ static void
> > > > mtk_smi_larb_config_port_gen2_general(struct device *dev)
> > > > if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_SW_FLAG))
> > > > writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base +
> > > > SMI_LARB_SW_FLAG);
> > > >
> > > > - for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd &&
> > > > !!larbostd[i]; i++)
> > > > + for (i = 0; i < SMI_LARB_PORT_NR_MAX && larb->larb_gen-
> > > > >ostd &&
> > > > !!larbostd[i]; i++)
> > > > writel_relaxed(larbostd[i], larb->base +
> > > > SMI_LARB_OSTDL_PORTx(i));
> > >
> > > The code does not look good. You have already a dereference at
> > > line
> > > 244:
> > >
> > > const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];
> >
> > if larb->larb_gen->ostd is null, larbostd is the offset, e.g. 0x80
> > in
> > the log above. thus, we can not use "larbostd[i]" in the "for"
> > loop.
> >
> > sorry for the unreadable. In this case, is the change ok?
>
> No, it's ok, I did not check the type of ostd and it's confusing a
> bit
> that it is defined as a pointer to an array but you actually use it
> as
> array of pointers to 32-elemenet arrays... Anyway I was mistaken and
> there will be indeed no dereference at the assignment, but for code
> clarity I would still prefer to do the check earlier, so:
>
> >
> > or like this:
> >
> > -const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];
> > +const u8 *larbostd = larb->larb_gen->ostd ? larb->larb_gen-
> > ostd[larb-
> > > larbid] : NULL;
>
> Although I think now the proper type should be explicit.
> mtk_smi_larb_mt8195_ostd is an 28-element array of
> SMI_LARB_PORT_NR_MAX-element u8 arrays, therefore struct
> mtk_smi_larb_gen should be:
> const u8 (*ostd)[][SMI_LARB_PORT_NR_MAX];

mt8195_ostd only is a 2 dimensional array,
static const u8 mtk_smi_larb_mt8195_ostd[][SMI_LARB_PORT_NR_MAX];

If using this, it will cause build fail:

.../drivers/memory/mtk-smi.c:359:23: error: initialization from
incompatible pointer type [-Werror=incompatible-pointer-types]
.ostd = mtk_smi_larb_mt8195_ostd,
^~~~~~~~~~~~~~~~~~~~~~~~

More background about this 2 dimensional array:
The platform have many larbs(up to MTK_LARB_NR_MAX), each a larb have
many ports(up to SMI_LARB_PORT_NR_MAX). In the
function(*_config_port_gen2_general), we will update the value for each
a port inside a larb, thus we need a pointer point to the line of that
larb.

If I miss something, please tell me. or how to manage this will be
better.

Thanks.

>
> Right?
>
>
> Best regards,
> Krzysztof