[v1] module: Fix device table module aliases

[PATCH] module: Fix device table module aliases

Posted by Josh Poimboeuf 3 months, 2 weeks ago

Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
__KBUILD_MODNAME") inadvertently broke module alias generation for
modules which rely on MODULE_DEVICE_TABLE().

It removed the "kmod_" prefix from __KBUILD_MODNAME, which caused
MODULE_DEVICE_TABLE() to generate a symbol name which no longer matched
the format expected by handle_moddevtable() in scripts/mod/file2alias.c.

As a result, modpost failed to find the device tables, leading to
missing module aliases.

Fix this by explicitly adding the "kmod_" string within the
MODULE_DEVICE_TABLE() macro itself, restoring the symbol name to the
format expected by file2alias.c.

Fixes: 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from __KBUILD_MODNAME")
Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reported-by: Mark Brown <broonie@kernel.org>
Reported-by: Cosmin Tanislav <demonsingur@gmail.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 include/linux/module.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index e135cc79aceea..d80c3ea574726 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -251,10 +251,11 @@ struct module_kobject *lookup_or_create_module_kobject(const char *name);
  */
 #define __mod_device_table(type, name)	\
 	__PASTE(__mod_device_table__,	\
+	__PASTE(kmod_,			\
 	__PASTE(__KBUILD_MODNAME,	\
 	__PASTE(__,			\
 	__PASTE(type,			\
-	__PASTE(__, name)))))
+	__PASTE(__, name))))))
 
 /* Creates an alias so file2alias.c can find device table. */
 #define MODULE_DEVICE_TABLE(type, name)					\
-- 
2.51.0

Re: [PATCH] module: Fix device table module aliases

Posted by Venkat 3 months, 2 weeks ago


> On 20 Oct 2025, at 11:23 PM, Josh Poimboeuf <jpoimboe@kernel.org> wrote:
> 
> Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
> __KBUILD_MODNAME") inadvertently broke module alias generation for
> modules which rely on MODULE_DEVICE_TABLE().
> 
> It removed the "kmod_" prefix from __KBUILD_MODNAME, which caused
> MODULE_DEVICE_TABLE() to generate a symbol name which no longer matched
> the format expected by handle_moddevtable() in scripts/mod/file2alias.c.
> 
> As a result, modpost failed to find the device tables, leading to
> missing module aliases.
> 
> Fix this by explicitly adding the "kmod_" string within the
> MODULE_DEVICE_TABLE() macro itself, restoring the symbol name to the
> format expected by file2alias.c.


IBM CI has also encountered this issue. I have tested this patch and it fixes the same.

Report link: https://lore.kernel.org/all/cdf7c458-b28f-4657-8708-1f820369baa6@linux.ibm.com/

Please add below tags.

Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>

Regards,
Venkat.


> Fixes: 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from __KBUILD_MODNAME")
> Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Reported-by: Mark Brown <broonie@kernel.org>
> Reported-by: Cosmin Tanislav <demonsingur@gmail.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
> ---
> include/linux/module.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/module.h b/include/linux/module.h
> index e135cc79aceea..d80c3ea574726 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -251,10 +251,11 @@ struct module_kobject *lookup_or_create_module_kobject(const char *name);
>  */
> #define __mod_device_table(type, name) \
> __PASTE(__mod_device_table__, \
> + __PASTE(kmod_, \
> __PASTE(__KBUILD_MODNAME, \
> __PASTE(__, \
> __PASTE(type, \
> - __PASTE(__, name)))))
> + __PASTE(__, name))))))
> 
> /* Creates an alias so file2alias.c can find device table. */
> #define MODULE_DEVICE_TABLE(type, name) \
> -- 
> 2.51.0
>

Re: [PATCH] module: Fix device table module aliases

Posted by Mark Brown 3 months, 2 weeks ago

On Mon, Oct 20, 2025 at 10:53:40AM -0700, Josh Poimboeuf wrote:

> Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
> __KBUILD_MODNAME") inadvertently broke module alias generation for
> modules which rely on MODULE_DEVICE_TABLE().

It'd be really good to get this fix applied, modules not loading is
hugely impacting CI coverage for -next - a lot of systems aren't even
able to get their rootfs due to the drivers for it being built as
modules.

Re: [PATCH] module: Fix device table module aliases

Posted by Peter Zijlstra 3 months, 2 weeks ago

On Wed, Oct 22, 2025 at 01:01:40PM +0100, Mark Brown wrote:
> On Mon, Oct 20, 2025 at 10:53:40AM -0700, Josh Poimboeuf wrote:
> 
> > Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
> > __KBUILD_MODNAME") inadvertently broke module alias generation for
> > modules which rely on MODULE_DEVICE_TABLE().
> 
> It'd be really good to get this fix applied, modules not loading is
> hugely impacting CI coverage for -next - a lot of systems aren't even
> able to get their rootfs due to the drivers for it being built as
> modules.

Oh, this needs to go in tip/objtool/core ? This wasn't immediately
obvious to me.

Let me go queue that then.

Re: [PATCH] module: Fix device table module aliases

Posted by Chen-Yu Tsai 3 months, 2 weeks ago

On Mon, Oct 20, 2025 at 10:53:40AM -0700, Josh Poimboeuf wrote:
> Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
> __KBUILD_MODNAME") inadvertently broke module alias generation for
> modules which rely on MODULE_DEVICE_TABLE().
> 
> It removed the "kmod_" prefix from __KBUILD_MODNAME, which caused
> MODULE_DEVICE_TABLE() to generate a symbol name which no longer matched
> the format expected by handle_moddevtable() in scripts/mod/file2alias.c.
> 
> As a result, modpost failed to find the device tables, leading to
> missing module aliases.
> 
> Fix this by explicitly adding the "kmod_" string within the
> MODULE_DEVICE_TABLE() macro itself, restoring the symbol name to the
> format expected by file2alias.c.
> 
> Fixes: 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from __KBUILD_MODNAME")
> Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Reported-by: Mark Brown <broonie@kernel.org>
> Reported-by: Cosmin Tanislav <demonsingur@gmail.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

Tested-by: Chen-Yu Tsai <wenst@chromium.org>

Re: [PATCH] module: Fix device table module aliases

Posted by Mark Brown 3 months, 2 weeks ago

On Mon, Oct 20, 2025 at 10:53:40AM -0700, Josh Poimboeuf wrote:
> Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
> __KBUILD_MODNAME") inadvertently broke module alias generation for
> modules which rely on MODULE_DEVICE_TABLE().
> 
> It removed the "kmod_" prefix from __KBUILD_MODNAME, which caused
> MODULE_DEVICE_TABLE() to generate a symbol name which no longer matched
> the format expected by handle_moddevtable() in scripts/mod/file2alias.c.

I've not done an exhaustive test of all the impacted platforms but this
looks like it fixes things:

Tested-by: Mark Brown <broonie@kernel.org>

Re: [PATCH] module: Fix device table module aliases

Posted by Marek Szyprowski 3 months, 2 weeks ago

On 20.10.2025 19:53, Josh Poimboeuf wrote:
> Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
> __KBUILD_MODNAME") inadvertently broke module alias generation for
> modules which rely on MODULE_DEVICE_TABLE().
>
> It removed the "kmod_" prefix from __KBUILD_MODNAME, which caused
> MODULE_DEVICE_TABLE() to generate a symbol name which no longer matched
> the format expected by handle_moddevtable() in scripts/mod/file2alias.c.
>
> As a result, modpost failed to find the device tables, leading to
> missing module aliases.
>
> Fix this by explicitly adding the "kmod_" string within the
> MODULE_DEVICE_TABLE() macro itself, restoring the symbol name to the
> format expected by file2alias.c.
>
> Fixes: 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from __KBUILD_MODNAME")
> Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Reported-by: Mark Brown <broonie@kernel.org>
> Reported-by: Cosmin Tanislav <demonsingur@gmail.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

This fixes the issue observed on my test systems. Thanks!

Closes: 
https://lore.kernel.org/all/d7b49971-8d77-43e2-b0cd-a70c6463ea57@samsung.com/
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>


> ---
>   include/linux/module.h | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/module.h b/include/linux/module.h
> index e135cc79aceea..d80c3ea574726 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -251,10 +251,11 @@ struct module_kobject *lookup_or_create_module_kobject(const char *name);
>    */
>   #define __mod_device_table(type, name)	\
>   	__PASTE(__mod_device_table__,	\
> +	__PASTE(kmod_,			\
>   	__PASTE(__KBUILD_MODNAME,	\
>   	__PASTE(__,			\
>   	__PASTE(type,			\
> -	__PASTE(__, name)))))
> +	__PASTE(__, name))))))
>   
>   /* Creates an alias so file2alias.c can find device table. */
>   #define MODULE_DEVICE_TABLE(type, name)					\

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH] module: Fix device table module aliases

Posted by Cosmin Tanislav 3 months, 2 weeks ago

On 10/20/25 8:53 PM, Josh Poimboeuf wrote:
> Commit 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from
> __KBUILD_MODNAME") inadvertently broke module alias generation for
> modules which rely on MODULE_DEVICE_TABLE().
> 
> It removed the "kmod_" prefix from __KBUILD_MODNAME, which caused
> MODULE_DEVICE_TABLE() to generate a symbol name which no longer matched
> the format expected by handle_moddevtable() in scripts/mod/file2alias.c.
> 
> As a result, modpost failed to find the device tables, leading to
> missing module aliases.
> 
> Fix this by explicitly adding the "kmod_" string within the
> MODULE_DEVICE_TABLE() macro itself, restoring the symbol name to the
> format expected by file2alias.c.
> 
> Fixes: 6717e8f91db7 ("kbuild: Remove 'kmod_' prefix from __KBUILD_MODNAME")
> Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Reported-by: Mark Brown <broonie@kernel.org>
> Reported-by: Cosmin Tanislav <demonsingur@gmail.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

Tested-by: Cosmin Tanislav <demonsingur@gmail.com>

> ---
>   include/linux/module.h | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/module.h b/include/linux/module.h
> index e135cc79aceea..d80c3ea574726 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -251,10 +251,11 @@ struct module_kobject *lookup_or_create_module_kobject(const char *name);
>    */
>   #define __mod_device_table(type, name)	\
>   	__PASTE(__mod_device_table__,	\
> +	__PASTE(kmod_,			\
>   	__PASTE(__KBUILD_MODNAME,	\
>   	__PASTE(__,			\
>   	__PASTE(type,			\
> -	__PASTE(__, name)))))
> +	__PASTE(__, name))))))
>   
>   /* Creates an alias so file2alias.c can find device table. */
>   #define MODULE_DEVICE_TABLE(type, name)					\