From: Ammar Faizi <ammarfaizi2@gnuweeb.org> Compiling with clang-16: drivers/base/module.c:36:6: error: variable 'no_warn' set but not \ used [-Werror,-Wunused-but-set-variable] int no_warn; ^ 1 error generated. A reason the @no_warn variable exists is: sysfs_create_link() return value needs not be ignored to silence another warning. So don't remove @no_warn, but add a '(void)no_warn;'. Cc: LLVM Mailing List <llvm@lists.linux.dev> Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org> --- drivers/base/module.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/base/module.c b/drivers/base/module.c index 46ad4d636731..42f0b3b9e7f8 100644 --- a/drivers/base/module.c +++ b/drivers/base/module.c @@ -59,22 +59,23 @@ void module_add_driver(struct module *mod, struct device_driver *drv) return; /* Don't check return codes; these calls are idempotent */ no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module"); driver_name = make_driver_name(drv); if (driver_name) { module_create_drivers_dir(mk); no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj, driver_name); kfree(driver_name); } + (void)no_warn; } void module_remove_driver(struct device_driver *drv) { struct module_kobject *mk = NULL; char *driver_name; if (!drv) return; sysfs_remove_link(&drv->p->kobj, "module"); base-commit: 8395ae05cb5a2e31d36106e8c85efa11cda849be -- Ammar Faizi
On Fri, Dec 23, 2022 at 09:51:37PM +0700, Ammar Faizi wrote:
> From: Ammar Faizi <ammarfaizi2@gnuweeb.org>
>
> Compiling with clang-16:
>
> drivers/base/module.c:36:6: error: variable 'no_warn' set but not \
> used [-Werror,-Wunused-but-set-variable]
> int no_warn;
> ^
> 1 error generated.
>
> A reason the @no_warn variable exists is:
> sysfs_create_link() return value needs not be ignored to silence
> another warning.
>
> So don't remove @no_warn, but add a '(void)no_warn;'.
>
> Cc: LLVM Mailing List <llvm@lists.linux.dev>
> Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
> ---
> drivers/base/module.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/base/module.c b/drivers/base/module.c
> index 46ad4d636731..42f0b3b9e7f8 100644
> --- a/drivers/base/module.c
> +++ b/drivers/base/module.c
> @@ -59,22 +59,23 @@ void module_add_driver(struct module *mod, struct device_driver *drv)
> return;
>
> /* Don't check return codes; these calls are idempotent */
> no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
> driver_name = make_driver_name(drv);
> if (driver_name) {
> module_create_drivers_dir(mk);
> no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj,
> driver_name);
> kfree(driver_name);
> }
> + (void)no_warn;
Ick, no, that's horrid and is NOT ok for kernel code, sorry.
Please fix the compiler, this is not a "fix" in any sense of the word
and is not going to work at all for kernel code.
sorry,
greg k-h
On 12/23/22 10:02 PM, Greg Kroah-Hartman wrote:
> Ick, no, that's horrid and is NOT ok for kernel code, sorry.
>
> Please fix the compiler, this is not a "fix" in any sense of the word
> and is not going to work at all for kernel code.
Agree.
Sorry for the noise. It turned out I messed up my clang compiler flags.
I forgot to do a "git reset --hard" before recompiling.
This has nothing todo with the upstream kernel.
--
Ammar Faizi
On Fri, Dec 23, 2022 at 10:31:57PM +0700, Ammar Faizi wrote: > On 12/23/22 10:02 PM, Greg Kroah-Hartman wrote: > > Ick, no, that's horrid and is NOT ok for kernel code, sorry. > > > > Please fix the compiler, this is not a "fix" in any sense of the word > > and is not going to work at all for kernel code. It is possible that the compiler should not emit -Wunused-but-set-variable when the variable is assigned the return value of a function marked with __attribute__((warn_unused_result)) but neither compiler does that today, you'll see the exact same warning from GCC 12.2.0: drivers/base/module.c: In function ‘module_add_driver’: drivers/base/module.c:36:13: error: variable ‘no_warn’ set but not used [-Werror=unused-but-set-variable] 36 | int no_warn; | ^~~~~~~ cc1: all warnings being treated as errors This has come up before too: https://lore.kernel.org/20210726201924.3202278-2-morbo@google.com/ > Agree. > > Sorry for the noise. It turned out I messed up my clang compiler flags. > I forgot to do a "git reset --hard" before recompiling. > > This has nothing todo with the upstream kernel. This warning is in W=1, which are warnings that we want to turn on at some point but the current instances need to be fixed first, so I would say this is still relevant to the upstream kernel. Cheers, Nathan