Re: [PATCH] [v3] module: don't ignore sysfs_create_link() failures

[Greg Kroah-Hartman]

On Tue, Mar 26, 2024 at 03:57:18PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> The sysfs_create_link() return code is marked as __must_check, but the
> module_add_driver() function tries hard to not care, by assigning the
> return code to a variable. When building with 'make W=1', gcc still
> warns because this variable is only assigned but not used:
> 
> drivers/base/module.c: In function 'module_add_driver':
> drivers/base/module.c:36:6: warning: variable 'no_warn' set but not used [-Wunused-but-set-variable]
> 
> Rework the code to properly unwind and return the error code to the
> caller. My reading of the original code was that it tries to
> not fail when the links already exist, so keep ignoring -EEXIST
> errors.
> 
> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> Cc: linux-modules@xxxxxxxxxxxxxxx
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
> Fixes: e17e0f51aeea ("Driver core: show drivers in /sys/module/")
> See-also: 4a7fb6363f2d ("add __must_check to device management code")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> v3: make error handling stricter, add unwinding,
>      fix build fail with CONFIG_MODULES=n
> v2: rework to actually handle the error. I have not tested the
>     error handling beyond build testing, so please review carefully.
> ---
>  drivers/base/base.h   |  9 ++++++---
>  drivers/base/bus.c    |  9 ++++++++-
>  drivers/base/module.c | 42 +++++++++++++++++++++++++++++++-----------
>  3 files changed, 45 insertions(+), 15 deletions(-)

Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>