[PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[Borislav Petkov]

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Have the driver depend on DEBUG_FS as it is useless without it.

Fixes: 6f15e617cc99 ("RAS: Introduce a FRU memory poison manager")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218640
Reported-by: anthony s.k. <akira.2020@protonmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Yazen Ghannam <yazen.ghannam@amd.com>
---
 drivers/ras/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ras/Kconfig b/drivers/ras/Kconfig
index fc4f4bb94a4c..41697e326fa6 100644
--- a/drivers/ras/Kconfig
+++ b/drivers/ras/Kconfig
@@ -37,7 +37,7 @@ source "drivers/ras/amd/atl/Kconfig"
 config RAS_FMPM
 	tristate "FRU Memory Poison Manager"
 	default m
-	depends on AMD_ATL && ACPI_APEI
+	depends on AMD_ATL && ACPI_APEI && DEBUG_FS
 	help
 	  Support saving and restoring memory error information across reboot
 	  using ACPI ERST as persistent storage. Error information is saved with
-- 
2.43.0

Re: [PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[Yazen Ghannam]

On 3/25/24 14:37, Borislav Petkov wrote:
> From: "Borislav Petkov (AMD)" <bp@alien8.de>
> 
> Have the driver depend on DEBUG_FS as it is useless without it.

This isn't true which is why the module doesn't fail to load if debugfs
is not available.

> 
> Fixes: 6f15e617cc99 ("RAS: Introduce a FRU memory poison manager")
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218640
> Reported-by: anthony s.k. <akira.2020@protonmail.com>
> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
> Cc: Yazen Ghannam <yazen.ghannam@amd.com>
> ---
>   drivers/ras/Kconfig | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/ras/Kconfig b/drivers/ras/Kconfig
> index fc4f4bb94a4c..41697e326fa6 100644
> --- a/drivers/ras/Kconfig
> +++ b/drivers/ras/Kconfig
> @@ -37,7 +37,7 @@ source "drivers/ras/amd/atl/Kconfig"
>   config RAS_FMPM
>   	tristate "FRU Memory Poison Manager"
>   	default m
> -	depends on AMD_ATL && ACPI_APEI
> +	depends on AMD_ATL && ACPI_APEI && DEBUG_FS

This was my first thought too. However, besides not true as stated
above, this also leaves the issue open for others to hit.

I think the fix below (not tested) would be more appropriate.

What do you think?

Thanks,
Yazen

diff --git a/drivers/ras/debugfs.h b/drivers/ras/debugfs.h
index 4749ccdeeba1..ab95831e7710 100644
--- a/drivers/ras/debugfs.h
+++ b/drivers/ras/debugfs.h
@@ -4,6 +4,10 @@

  #include <linux/debugfs.h>

+#if IS_ENABLED(DEBUG_FS)
  struct dentry *ras_get_debugfs_root(void);
+#else
+static inline struct dentry *ras_get_debugfs_root(void) { return NULL; }
+#endif /* DEBUG_FS */

  #endif /* __RAS_DEBUGFS_H__ */

Re: [PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[Borislav Petkov]

On Tue, Mar 26, 2024 at 09:41:41AM -0400, Yazen Ghannam wrote:
> This isn't true which is why the module doesn't fail to load if debugfs
> is not available.

How useful is this thing really without debugfs to dump records?

> This was my first thought too. However, besides not true as stated
> above, this also leaves the issue open for others to hit.

The others to hit? I don't get that part.

> I think the fix below (not tested) would be more appropriate.
> 
> What do you think?

Sure, remove my fix and send me a tested version of yours and I'll swap
them if the driver is useful without debugfs...

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[A]

On Tuesday, March 26th, 2024 at 13:41, Yazen Ghannam <yazen.ghannam@amd.com> wrote:

> 
> 
> 
> On 3/25/24 14:37, Borislav Petkov wrote:
> 
> > From: "Borislav Petkov (AMD)" bp@alien8.de
> > 
> > Have the driver depend on DEBUG_FS as it is useless without it.
> 
> 
> This isn't true which is why the module doesn't fail to load if debugfs
> is not available.
> 
> > Fixes: 6f15e617cc99 ("RAS: Introduce a FRU memory poison manager")
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218640
> > Reported-by: anthony s.k. akira.2020@protonmail.com
> > Signed-off-by: Borislav Petkov (AMD) bp@alien8.de
> > Cc: Yazen Ghannam yazen.ghannam@amd.com
> > ---
> > drivers/ras/Kconfig | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/ras/Kconfig b/drivers/ras/Kconfig
> > index fc4f4bb94a4c..41697e326fa6 100644
> > --- a/drivers/ras/Kconfig
> > +++ b/drivers/ras/Kconfig
> > @@ -37,7 +37,7 @@ source "drivers/ras/amd/atl/Kconfig"
> > config RAS_FMPM
> > tristate "FRU Memory Poison Manager"
> > default m
> > - depends on AMD_ATL && ACPI_APEI
> > + depends on AMD_ATL && ACPI_APEI && DEBUG_FS
> 
> 
> This was my first thought too. However, besides not true as stated
> above, this also leaves the issue open for others to hit.
> 
> I think the fix below (not tested) would be more appropriate.
> 
> What do you think?
> 
> Thanks,
> Yazen
> 
> diff --git a/drivers/ras/debugfs.h b/drivers/ras/debugfs.h
> index 4749ccdeeba1..ab95831e7710 100644
> --- a/drivers/ras/debugfs.h
> +++ b/drivers/ras/debugfs.h
> @@ -4,6 +4,10 @@
> 
> #include <linux/debugfs.h>
> 
> 
> +#if IS_ENABLED(DEBUG_FS)
> struct dentry *ras_get_debugfs_root(void);
> +#else
> +static inline struct dentry ras_get_debugfs_root(void) { return NULL; }
> +#endif / DEBUG_FS /
> 
> #endif / RAS_DEBUGFS_H */

this also works, just tested

this time round, `make oldconfig` asks if i want to build RAS_FMPM, i built it as module, compilation succeeds.

thanks

kind regards,
anthony s.k.

Re: [PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[Yazen Ghannam]

On 3/26/24 10:07, Borislav Petkov wrote:
> On Tue, Mar 26, 2024 at 09:41:41AM -0400, Yazen Ghannam wrote:
>> This isn't true which is why the module doesn't fail to load if debugfs
>> is not available.
> 
> How useful is this thing really without debugfs to dump records?
>

The goal of the module is to save and restore records across reboots.

The debugfs thing came later and the commit message states that it is
optional.

7d19eea51757 ("RAS/AMD/FMPM: Add debugfs interface to print record entries")

>> This was my first thought too. However, besides not true as stated
>> above, this also leaves the issue open for others to hit.
> 
> The others to hit? I don't get that part.
>

Sorry, I mean that if there's another user of ras_get_debugfs_root()
that doesn't depend on CONFIG_DEBUG_FS.

>> I think the fix below (not tested) would be more appropriate.
>>
>> What do you think?
> 
> Sure, remove my fix and send me a tested version of yours and I'll swap
> them if the driver is useful without debugfs...

Okay, will do.

Thanks,
Yazen

Re: [PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[Borislav Petkov]

On Tue, Mar 26, 2024 at 10:22:05AM -0400, Yazen Ghannam wrote:
> The goal of the module is to save and restore records across reboots.

I guess... although when you think about it, you'd want to dump records
and see what got restored. But ok, strictly speaking, I guess debugfs is
optional...

> Sorry, I mean that if there's another user of ras_get_debugfs_root()
> that doesn't depend on CONFIG_DEBUG_FS.

That is true.

> Okay, will do.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[Yazen Ghannam]

On 3/26/24 10:20, A wrote:
[...]
>>
>> diff --git a/drivers/ras/debugfs.h b/drivers/ras/debugfs.h
>> index 4749ccdeeba1..ab95831e7710 100644
>> --- a/drivers/ras/debugfs.h
>> +++ b/drivers/ras/debugfs.h
>> @@ -4,6 +4,10 @@
>>
>> #include <linux/debugfs.h>
>>
>>
>> +#if IS_ENABLED(DEBUG_FS)
>> struct dentry *ras_get_debugfs_root(void);
>> +#else
>> +static inline struct dentry ras_get_debugfs_root(void) { return NULL; }
>> +#endif / DEBUG_FS /
>>
>> #endif / RAS_DEBUGFS_H */
> 
> this also works, just tested
> 
> this time round, `make oldconfig` asks if i want to build RAS_FMPM, i built it as module, compilation succeeds.
> 

Thanks for testing!

Would you mind including your "Tested-by" tag? I can include this when I 
send a proper patch.

Thanks,
Yazen

Re: [PATCH] RAS/AMD/FMPM: Fix build when debugfs is not enabled

[A]

On Tuesday, March 26th, 2024 at 14:29, Yazen Ghannam <yazen.ghannam@amd.com> wrote:

> 
> 
> On 3/26/24 10:20, A wrote:
> [...]
> 
> > > diff --git a/drivers/ras/debugfs.h b/drivers/ras/debugfs.h
> > > index 4749ccdeeba1..ab95831e7710 100644
> > > --- a/drivers/ras/debugfs.h
> > > +++ b/drivers/ras/debugfs.h
> > > @@ -4,6 +4,10 @@
> > > 
> > > #include <linux/debugfs.h>
> > > 
> > > +#if IS_ENABLED(DEBUG_FS)
> > > struct dentry *ras_get_debugfs_root(void);
> > > +#else
> > > +static inline struct dentry ras_get_debugfs_root(void) { return NULL; }
> > > +#endif / DEBUG_FS /
> > > 
> > > #endif / RAS_DEBUGFS_H */
> > 
> > this also works, just tested
> > 
> > this time round, `make oldconfig` asks if i want to build RAS_FMPM, i built it as module, compilation succeeds.
> 
> 
> Thanks for testing!
> 
> Would you mind including your "Tested-by" tag? I can include this when I
> send a proper patch.
> 
> Thanks,
> Yazen

sure, tested-by:  anthony s. knowles <akira.2020@protonmail.com>

kind regards,
a.s.k