[PATCH] clk: ralink: mtmips: Fix uninitialized use of ret in mtmips_register_{fixed,factor}_clocks()

[PATCH] clk: ralink: mtmips: Fix uninitialized use of ret in mtmips_register_{fixed,factor}_clocks()

[Nathan Chancellor]

Clang warns:

  drivers/clk/ralink/clk-mtmips.c:309:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
    309 |         return ret;
        |                ^~~
  drivers/clk/ralink/clk-mtmips.c:285:9: note: initialize the variable 'ret' to silence this warning
    285 |         int ret, i;
        |                ^
        |                 = 0
  drivers/clk/ralink/clk-mtmips.c:359:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
    359 |         return ret;
        |                ^~~
  drivers/clk/ralink/clk-mtmips.c:335:9: note: initialize the variable 'ret' to silence this warning
    335 |         int ret, i;
        |                ^
        |                 = 0
  2 errors generated.

Set ret to the return value of clk_hw_register_fixed_rate() using the
PTR_ERR() macro, which ensures ret is not used uninitialized, clearing
up the warning.

Fixes: 6f3b15586eef ("clk: ralink: add clock and reset driver for MTMIPS SoCs")
Closes: https://github.com/ClangBuiltLinux/linux/issues/1879
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/clk/ralink/clk-mtmips.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/clk/ralink/clk-mtmips.c b/drivers/clk/ralink/clk-mtmips.c
index 9322c6210a33..1e7991439527 100644
--- a/drivers/clk/ralink/clk-mtmips.c
+++ b/drivers/clk/ralink/clk-mtmips.c
@@ -292,6 +292,7 @@ static int mtmips_register_fixed_clocks(struct clk_hw_onecell_data *clk_data,
 						      sclk->parent, 0,
 						      sclk->rate);
 		if (IS_ERR(sclk->hw)) {
+			ret = PTR_ERR(sclk->hw);
 			pr_err("Couldn't register fixed clock %d\n", idx);
 			goto err_clk_unreg;
 		}
@@ -342,6 +343,7 @@ static int mtmips_register_factor_clocks(struct clk_hw_onecell_data *clk_data,
 						  sclk->parent, sclk->flags,
 						  sclk->mult, sclk->div);
 		if (IS_ERR(sclk->hw)) {
+			ret = PTR_ERR(sclk->hw);
 			pr_err("Couldn't register factor clock %d\n", idx);
 			goto err_clk_unreg;
 		}

---
base-commit: fd99ac5055d4705e91c73d1adba18bc71c8511a8
change-id: 20230622-mips-ralink-clk-wuninitialized-150bd0336187

Best regards,
-- 
Nathan Chancellor <nathan@kernel.org>

Re: [PATCH] clk: ralink: mtmips: Fix uninitialized use of ret in mtmips_register_{fixed,factor}_clocks()

[Nick Desaulniers]

On Thu, Jun 22, 2023 at 8:56 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> Clang warns:
>
>   drivers/clk/ralink/clk-mtmips.c:309:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
>     309 |         return ret;
>         |                ^~~
>   drivers/clk/ralink/clk-mtmips.c:285:9: note: initialize the variable 'ret' to silence this warning
>     285 |         int ret, i;
>         |                ^
>         |                 = 0
>   drivers/clk/ralink/clk-mtmips.c:359:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
>     359 |         return ret;
>         |                ^~~
>   drivers/clk/ralink/clk-mtmips.c:335:9: note: initialize the variable 'ret' to silence this warning
>     335 |         int ret, i;
>         |                ^
>         |                 = 0
>   2 errors generated.
>
> Set ret to the return value of clk_hw_register_fixed_rate() using the
> PTR_ERR() macro, which ensures ret is not used uninitialized, clearing
> up the warning.
>
> Fixes: 6f3b15586eef ("clk: ralink: add clock and reset driver for MTMIPS SoCs")
> Closes: https://github.com/ClangBuiltLinux/linux/issues/1879
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Thanks for the patch!
PTR_ERR returns a long; assigning to an int risks truncation of the
error.  The use of PTR_ERR on L1079 has a similar risk...]

Maybe Sergio wants to revisit that in more detail, but this at least
fixes the build for us.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  drivers/clk/ralink/clk-mtmips.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/clk/ralink/clk-mtmips.c b/drivers/clk/ralink/clk-mtmips.c
> index 9322c6210a33..1e7991439527 100644
> --- a/drivers/clk/ralink/clk-mtmips.c
> +++ b/drivers/clk/ralink/clk-mtmips.c
> @@ -292,6 +292,7 @@ static int mtmips_register_fixed_clocks(struct clk_hw_onecell_data *clk_data,
>                                                       sclk->parent, 0,
>                                                       sclk->rate);
>                 if (IS_ERR(sclk->hw)) {
> +                       ret = PTR_ERR(sclk->hw);
>                         pr_err("Couldn't register fixed clock %d\n", idx);
>                         goto err_clk_unreg;
>                 }
> @@ -342,6 +343,7 @@ static int mtmips_register_factor_clocks(struct clk_hw_onecell_data *clk_data,
>                                                   sclk->parent, sclk->flags,
>                                                   sclk->mult, sclk->div);
>                 if (IS_ERR(sclk->hw)) {
> +                       ret = PTR_ERR(sclk->hw);
>                         pr_err("Couldn't register factor clock %d\n", idx);
>                         goto err_clk_unreg;
>                 }
>
> ---
> base-commit: fd99ac5055d4705e91c73d1adba18bc71c8511a8
> change-id: 20230622-mips-ralink-clk-wuninitialized-150bd0336187
>
> Best regards,
> --
> Nathan Chancellor <nathan@kernel.org>
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH] clk: ralink: mtmips: Fix uninitialized use of ret in mtmips_register_{fixed,factor}_clocks()

[Sergio Paracuellos]

On Thu, Jun 22, 2023 at 5:56 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> Clang warns:
>
>   drivers/clk/ralink/clk-mtmips.c:309:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
>     309 |         return ret;
>         |                ^~~
>   drivers/clk/ralink/clk-mtmips.c:285:9: note: initialize the variable 'ret' to silence this warning
>     285 |         int ret, i;
>         |                ^
>         |                 = 0
>   drivers/clk/ralink/clk-mtmips.c:359:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
>     359 |         return ret;
>         |                ^~~
>   drivers/clk/ralink/clk-mtmips.c:335:9: note: initialize the variable 'ret' to silence this warning
>     335 |         int ret, i;
>         |                ^
>         |                 = 0
>   2 errors generated.
>
> Set ret to the return value of clk_hw_register_fixed_rate() using the
> PTR_ERR() macro, which ensures ret is not used uninitialized, clearing
> up the warning.
>
> Fixes: 6f3b15586eef ("clk: ralink: add clock and reset driver for MTMIPS SoCs")
> Closes: https://github.com/ClangBuiltLinux/linux/issues/1879
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  drivers/clk/ralink/clk-mtmips.c | 2 ++
>  1 file changed, 2 insertions(+)

Thanks for the patch, Nathan!!

Acked-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>

Best regards,
    Sergio Paracuellos

Re: [PATCH] clk: ralink: mtmips: Fix uninitialized use of ret in mtmips_register_{fixed,factor}_clocks()

[Dan Carpenter]

On Thu, Jun 22, 2023 at 09:36:53AM -0700, Nick Desaulniers wrote:
> On Thu, Jun 22, 2023 at 8:56 AM Nathan Chancellor <nathan@kernel.org> wrote:
> >
> > Clang warns:
> >
> >   drivers/clk/ralink/clk-mtmips.c:309:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
> >     309 |         return ret;
> >         |                ^~~
> >   drivers/clk/ralink/clk-mtmips.c:285:9: note: initialize the variable 'ret' to silence this warning
> >     285 |         int ret, i;
> >         |                ^
> >         |                 = 0
> >   drivers/clk/ralink/clk-mtmips.c:359:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
> >     359 |         return ret;
> >         |                ^~~
> >   drivers/clk/ralink/clk-mtmips.c:335:9: note: initialize the variable 'ret' to silence this warning
> >     335 |         int ret, i;
> >         |                ^
> >         |                 = 0
> >   2 errors generated.
> >
> > Set ret to the return value of clk_hw_register_fixed_rate() using the
> > PTR_ERR() macro, which ensures ret is not used uninitialized, clearing
> > up the warning.
> >
> > Fixes: 6f3b15586eef ("clk: ralink: add clock and reset driver for MTMIPS SoCs")
> > Closes: https://github.com/ClangBuiltLinux/linux/issues/1879
> > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> 
> Thanks for the patch!
> PTR_ERR returns a long; assigning to an int risks truncation of the
> error.  The use of PTR_ERR on L1079 has a similar risk...]
> 

If PTR_ERR() ever returns anything outside of the (-4095)-(0) range then
we are already screwed.

I'm 90% sure there is a reason why PTR_ERR() returns long but I can't
think off the top of my head why that is...  It's been that way since
before the git era.  I could imagine type promotion bugs involving
u32 and int if we changed it.

	ssize_t ret_val = PTR_ERR(x) ?: u32_something;

Or maybe Linus just felt casting a pointer to int was ugly.

regards,
dan carpenter

Re: [PATCH] clk: ralink: mtmips: Fix uninitialized use of ret in mtmips_register_{fixed,factor}_clocks()

[Thomas Bogendoerfer]

On Thu, Jun 22, 2023 at 03:56:19PM +0000, Nathan Chancellor wrote:
> Clang warns:
> 
>   drivers/clk/ralink/clk-mtmips.c:309:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
>     309 |         return ret;
>         |                ^~~
>   drivers/clk/ralink/clk-mtmips.c:285:9: note: initialize the variable 'ret' to silence this warning
>     285 |         int ret, i;
>         |                ^
>         |                 = 0
>   drivers/clk/ralink/clk-mtmips.c:359:9: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
>     359 |         return ret;
>         |                ^~~
>   drivers/clk/ralink/clk-mtmips.c:335:9: note: initialize the variable 'ret' to silence this warning
>     335 |         int ret, i;
>         |                ^
>         |                 = 0
>   2 errors generated.
> 
> Set ret to the return value of clk_hw_register_fixed_rate() using the
> PTR_ERR() macro, which ensures ret is not used uninitialized, clearing
> up the warning.
> 
> Fixes: 6f3b15586eef ("clk: ralink: add clock and reset driver for MTMIPS SoCs")
> Closes: https://github.com/ClangBuiltLinux/linux/issues/1879
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  drivers/clk/ralink/clk-mtmips.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/clk/ralink/clk-mtmips.c b/drivers/clk/ralink/clk-mtmips.c
> index 9322c6210a33..1e7991439527 100644
> --- a/drivers/clk/ralink/clk-mtmips.c
> +++ b/drivers/clk/ralink/clk-mtmips.c
> @@ -292,6 +292,7 @@ static int mtmips_register_fixed_clocks(struct clk_hw_onecell_data *clk_data,
>  						      sclk->parent, 0,
>  						      sclk->rate);
>  		if (IS_ERR(sclk->hw)) {
> +			ret = PTR_ERR(sclk->hw);
>  			pr_err("Couldn't register fixed clock %d\n", idx);
>  			goto err_clk_unreg;
>  		}
> @@ -342,6 +343,7 @@ static int mtmips_register_factor_clocks(struct clk_hw_onecell_data *clk_data,
>  						  sclk->parent, sclk->flags,
>  						  sclk->mult, sclk->div);
>  		if (IS_ERR(sclk->hw)) {
> +			ret = PTR_ERR(sclk->hw);
>  			pr_err("Couldn't register factor clock %d\n", idx);
>  			goto err_clk_unreg;
>  		}
> 
> ---
> base-commit: fd99ac5055d4705e91c73d1adba18bc71c8511a8
> change-id: 20230622-mips-ralink-clk-wuninitialized-150bd0336187

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]