2021-03-22 11:57:18

by Arnd Bergmann

Subject: [PATCH] lockdep: address clang -Wformat warning printing for %hd

From: Arnd Bergmann <[email protected]>

Clang doesn't like format strings that truncate a 32-bit
value to something shorter:

kernel/locking/lockdep.c:709:4: error: format specifies type 'short' but the argument has type 'int' [-Werror,-Wformat]

In this case, the warning is a slightly questionable, as it could realize
that both class->wait_type_outer and class->wait_type_inner are in fact
8-bit struct members, even though the result of the ?: operator becomes an
'int'.

However, there is really no point in printing the number as a 16-bit
'short' rather than either an 8-bit or 32-bit number, so just change
it to a normal %d.

Fixes: de8f5e4f2dc1 ("lockdep: Introduce wait-type checks")
Signed-off-by: Arnd Bergmann <[email protected]>
---
kernel/locking/lockdep.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 70bf3e48eae3..bb3b0bc6ee17 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -705,7 +705,7 @@ static void print_lock_name(struct lock_class *class)

printk(KERN_CONT " (");
__print_lock_name(class);
- printk(KERN_CONT "){%s}-{%hd:%hd}", usage,
+ printk(KERN_CONT "){%s}-{%d:%d}", usage,
class->wait_type_outer ?: class->wait_type_inner,
class->wait_type_inner);
}
--
2.29.2

2021-03-22 21:13:31

by tip-bot2 for Oleg Nesterov

Subject: [tip: perf/urgent] lockdep: Address clang -Wformat warning printing for %hd

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID: 6d48b7912cc72275dc7c59ff961c8bac7ef66a92
Gitweb: https://git.kernel.org/tip/6d48b7912cc72275dc7c59ff961c8bac7ef66a92
Author: Arnd Bergmann <[email protected]>
AuthorDate: Mon, 22 Mar 2021 12:55:25 +01:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Mon, 22 Mar 2021 22:07:09 +01:00

lockdep: Address clang -Wformat warning printing for %hd

Clang doesn't like format strings that truncate a 32-bit
value to something shorter:

kernel/locking/lockdep.c:709:4: error: format specifies type 'short' but the argument has type 'int' [-Werror,-Wformat]

In this case, the warning is a slightly questionable, as it could realize
that both class->wait_type_outer and class->wait_type_inner are in fact
8-bit struct members, even though the result of the ?: operator becomes an
'int'.

However, there is really no point in printing the number as a 16-bit
'short' rather than either an 8-bit or 32-bit number, so just change
it to a normal %d.

Fixes: de8f5e4f2dc1 ("lockdep: Introduce wait-type checks")
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
kernel/locking/lockdep.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index c30eb88..f160f1c 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -705,7 +705,7 @@ static void print_lock_name(struct lock_class *class)

printk(KERN_CONT " (");
__print_lock_name(class);
- printk(KERN_CONT "){%s}-{%hd:%hd}", usage,
+ printk(KERN_CONT "){%s}-{%d:%d}", usage,
class->wait_type_outer ?: class->wait_type_inner,
class->wait_type_inner);
}

2021-03-29 18:27:41

by Nick Desaulniers

Subject: Re: [PATCH] lockdep: address clang -Wformat warning printing for %hd

On Mon, Mar 22, 2021 at 4:55 AM Arnd Bergmann <[email protected]> wrote:
>
> From: Arnd Bergmann <[email protected]>
>
> Clang doesn't like format strings that truncate a 32-bit
> value to something shorter:
>
> kernel/locking/lockdep.c:709:4: error: format specifies type 'short' but the argument has type 'int' [-Werror,-Wformat]
>
> In this case, the warning is a slightly questionable, as it could realize
> that both class->wait_type_outer and class->wait_type_inner are in fact
> 8-bit struct members, even though the result of the ?: operator becomes an
> 'int'.
>
> However, there is really no point in printing the number as a 16-bit
> 'short' rather than either an 8-bit or 32-bit number, so just change
> it to a normal %d.

Thanks for the patch!
Reviewed-by: Nick Desaulniers <[email protected]>

>
> Fixes: de8f5e4f2dc1 ("lockdep: Introduce wait-type checks")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> kernel/locking/lockdep.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index 70bf3e48eae3..bb3b0bc6ee17 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -705,7 +705,7 @@ static void print_lock_name(struct lock_class *class)
>
> printk(KERN_CONT " (");
> __print_lock_name(class);
> - printk(KERN_CONT "){%s}-{%hd:%hd}", usage,
> + printk(KERN_CONT "){%s}-{%d:%d}", usage,
> class->wait_type_outer ?: class->wait_type_inner,
> class->wait_type_inner);
> }
> --
> 2.29.2
>


--
Thanks,
~Nick Desaulniers