linux-kernel - Re: [PATCH] reboot: Fix variable assignments in type

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Message-ID: <20201113155659.GN1602@alley>
Date:   Fri, 13 Nov 2020 16:56:59 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     mcroce@...ux.microsoft.com, akpm@...ux-foundation.org,
        arnd@...db.de, keescook@...omium.org, linux-kernel@...r.kernel.org,
        linux@...ck-us.net, pasha.tatashin@...een.com, rppt@...nel.org,
        tyhicks@...ux.microsoft.com, ndesaulniers@...gle.com,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH] reboot: Fix variable assignments in type_store

On Wed 2020-11-11 20:50:23, Nathan Chancellor wrote:
> Clang warns:
> 
> kernel/reboot.c:707:17: warning: implicit conversion from enumeration
> type 'enum reboot_type' to different enumeration type 'enum reboot_mode'
> [-Wenum-conversion]
>                 reboot_mode = BOOT_TRIPLE;
>                             ~ ^~~~~~~~~~~
> kernel/reboot.c:709:17: warning: implicit conversion from enumeration
> type 'enum reboot_type' to different enumeration type 'enum reboot_mode'
> [-Wenum-conversion]
>                 reboot_mode = BOOT_KBD;
>                             ~ ^~~~~~~~
> kernel/reboot.c:711:17: warning: implicit conversion from enumeration
> type 'enum reboot_type' to different enumeration type 'enum reboot_mode'
> [-Wenum-conversion]
>                 reboot_mode = BOOT_BIOS;
>                             ~ ^~~~~~~~~
> kernel/reboot.c:713:17: warning: implicit conversion from enumeration
> type 'enum reboot_type' to different enumeration type 'enum reboot_mode'
> [-Wenum-conversion]
>                 reboot_mode = BOOT_ACPI;
>                             ~ ^~~~~~~~~
> kernel/reboot.c:715:17: warning: implicit conversion from enumeration
> type 'enum reboot_type' to different enumeration type 'enum reboot_mode'
> [-Wenum-conversion]
>                 reboot_mode = BOOT_EFI;
>                             ~ ^~~~~~~~
> kernel/reboot.c:717:17: warning: implicit conversion from enumeration
> type 'enum reboot_type' to different enumeration type 'enum reboot_mode'
> [-Wenum-conversion]
>                 reboot_mode = BOOT_CF9_FORCE;
>                             ~ ^~~~~~~~~~~~~~
> kernel/reboot.c:719:17: warning: implicit conversion from enumeration
> type 'enum reboot_type' to different enumeration type 'enum reboot_mode'
> [-Wenum-conversion]
>                 reboot_mode = BOOT_CF9_SAFE;
>                             ~ ^~~~~~~~~~~~~
> 7 warnings generated.
> 
> It seems that these assignment should be to reboot_type, not
> reboot_mode. Fix it so there are no more warnings and the code works
> properly.
> 
> Fixes: eab8da48579d ("reboot: allow to specify reboot mode via sysfs")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1197
> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> ---
>  kernel/reboot.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/reboot.c b/kernel/reboot.c
> index deba133a071b..8599d0d44aec 100644
> --- a/kernel/reboot.c
> +++ b/kernel/reboot.c
> @@ -704,19 +704,19 @@ static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
>  		return -EPERM;
>  
>  	if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
> -		reboot_mode = BOOT_TRIPLE;
> +		reboot_type = BOOT_TRIPLE;
>  	else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
> -		reboot_mode = BOOT_KBD;
> +		reboot_type = BOOT_KBD;
>  	else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
> -		reboot_mode = BOOT_BIOS;
> +		reboot_type = BOOT_BIOS;
>  	else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
> -		reboot_mode = BOOT_ACPI;
> +		reboot_type = BOOT_ACPI;
>  	else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
> -		reboot_mode = BOOT_EFI;
> +		reboot_type = BOOT_EFI;
>  	else if (!strncmp(buf, BOOT_CF9_FORCE_STR, strlen(BOOT_CF9_FORCE_STR)))
> -		reboot_mode = BOOT_CF9_FORCE;
> +		reboot_type = BOOT_CF9_FORCE;
>  	else if (!strncmp(buf, BOOT_CF9_SAFE_STR, strlen(BOOT_CF9_SAFE_STR)))
> -		reboot_mode = BOOT_CF9_SAFE;
> +		reboot_type = BOOT_CF9_SAFE;
>  	else
>  		return -EINVAL;

Great catch! I guess that it has been a cut&paste mistake when writing
the code.

I feel shame that I have missed it. I think that I have even tested it
but I probably tried only mode_store() and mode_read().

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr