2021-02-11 16:22:37

by Vincenzo Frascino

Subject: [PATCH v2] arm64: Fix warning in mte_get_random_tag()

The simplification of mte_get_random_tag() caused the introduction of the
warning below:

In file included from arch/arm64/include/asm/kasan.h:9,
from include/linux/kasan.h:16,
from mm/kasan/common.c:14:
mm/kasan/common.c: In function ‘mte_get_random_tag’:
arch/arm64/include/asm/mte-kasan.h:45:9: warning: ‘addr’ is used
uninitialized [-Wuninitialized]
45 | asm(__MTE_PREAMBLE "irg %0, %0"
|

Fix the warning using "=r" for the address in the asm inline.

Fixes: c8f8de4c0887 ("arm64: kasan: simplify and inline MTE functions")
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Vincenzo Frascino <[email protected]>
---

This patch is based on linux-next/akpm

arch/arm64/include/asm/mte-kasan.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h
index 3d58489228c0..7ab500e2ad17 100644
--- a/arch/arm64/include/asm/mte-kasan.h
+++ b/arch/arm64/include/asm/mte-kasan.h
@@ -43,7 +43,7 @@ static inline u8 mte_get_random_tag(void)
void *addr;

asm(__MTE_PREAMBLE "irg %0, %0"
- : "+r" (addr));
+ : "=r" (addr));

return mte_get_ptr_tag(addr);
}
--
2.30.0

2021-02-11 18:12:37

by Andrey Konovalov

Subject: Re: [PATCH v2] arm64: Fix warning in mte_get_random_tag()

On Thu, Feb 11, 2021 at 4:22 PM Vincenzo Frascino
<[email protected]> wrote:
>
> The simplification of mte_get_random_tag() caused the introduction of the
> warning below:
>
> In file included from arch/arm64/include/asm/kasan.h:9,
> from include/linux/kasan.h:16,
> from mm/kasan/common.c:14:
> mm/kasan/common.c: In function ‘mte_get_random_tag’:
> arch/arm64/include/asm/mte-kasan.h:45:9: warning: ‘addr’ is used
> uninitialized [-Wuninitialized]
> 45 | asm(__MTE_PREAMBLE "irg %0, %0"
> |
>
> Fix the warning using "=r" for the address in the asm inline.
>
> Fixes: c8f8de4c0887 ("arm64: kasan: simplify and inline MTE functions")
> Cc: Catalin Marinas <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Andrey Konovalov <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Signed-off-by: Vincenzo Frascino <[email protected]>
> ---
>
> This patch is based on linux-next/akpm
>
> arch/arm64/include/asm/mte-kasan.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h
> index 3d58489228c0..7ab500e2ad17 100644
> --- a/arch/arm64/include/asm/mte-kasan.h
> +++ b/arch/arm64/include/asm/mte-kasan.h
> @@ -43,7 +43,7 @@ static inline u8 mte_get_random_tag(void)
> void *addr;
>
> asm(__MTE_PREAMBLE "irg %0, %0"
> - : "+r" (addr));
> + : "=r" (addr));
>
> return mte_get_ptr_tag(addr);
> }
> --
> 2.30.0
>

Acked-by: Andrey Konovalov <[email protected]>
Tested-by: Andrey Konovalov <[email protected]>

2021-02-12 10:59:14

by Catalin Marinas

Subject: Re: [PATCH v2] arm64: Fix warning in mte_get_random_tag()

On Thu, Feb 11, 2021 at 03:22:08PM +0000, Vincenzo Frascino wrote:
> The simplification of mte_get_random_tag() caused the introduction of the
> warning below:
>
> In file included from arch/arm64/include/asm/kasan.h:9,
> from include/linux/kasan.h:16,
> from mm/kasan/common.c:14:
> mm/kasan/common.c: In function ‘mte_get_random_tag’:
> arch/arm64/include/asm/mte-kasan.h:45:9: warning: ‘addr’ is used
> uninitialized [-Wuninitialized]
> 45 | asm(__MTE_PREAMBLE "irg %0, %0"
> |
>
> Fix the warning using "=r" for the address in the asm inline.
>
> Fixes: c8f8de4c0887 ("arm64: kasan: simplify and inline MTE functions")
> Cc: Catalin Marinas <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Andrey Konovalov <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Signed-off-by: Vincenzo Frascino <[email protected]>

Acked-by: Catalin Marinas <[email protected]>