* Re: [PATCH] alpha: Silence -Warray-bounds warnings
@ 2022-02-02 23:17 Guenter Roeck
0 siblings, 0 replies; 2+ messages in thread
From: Guenter Roeck @ 2022-02-02 23:17 UTC (permalink / raw)
To: Kees Cook
Cc: Richard Henderson, Ivan Kokshaysky, Matt Turner, Arnd Bergmann,
linux-kernel, linux-alpha, linux-hardening
On Wed, Feb 02, 2022 at 02:18:25PM -0800, Kees Cook wrote:
> GCC 11 (incorrectly[1]) assumes that literal values cast to (void *)
> should be treated like a NULL pointer with an offset, and raises
> diagnostics when doing bounds checking:
>
> In function '__memset',
> inlined from '__bad_pagetable' at arch/alpha/mm/init.c:79:2:
> ./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds]
> 37 | return __builtin_memset(s, c, n);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~
> In function '__memset',
> inlined from '__bad_page' at arch/alpha/mm/init.c:86:2:
> ./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds]
> 37 | return __builtin_memset(s, c, n);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~
> In function '__memset',
> inlined from 'paging_init' at arch/alpha/mm/init.c:256:2:
> ./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds]
> 37 | return __builtin_memset(s, c, n);
>
> This has been solved in other places[2] already by using the recently
> added absolute_pointer() macro. Do the same here.
>
> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
> [2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-and-tested-by: Guenter Roeck <linux@roeck-us.net>
> ---
> arch/alpha/mm/init.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c
> index f6114d03357c..7511723b7669 100644
> --- a/arch/alpha/mm/init.c
> +++ b/arch/alpha/mm/init.c
> @@ -76,14 +76,14 @@ pgd_alloc(struct mm_struct *mm)
> pmd_t *
> __bad_pagetable(void)
> {
> - memset((void *) EMPTY_PGT, 0, PAGE_SIZE);
> + memset(absolute_pointer(EMPTY_PGT), 0, PAGE_SIZE);
> return (pmd_t *) EMPTY_PGT;
> }
>
> pte_t
> __bad_page(void)
> {
> - memset((void *) EMPTY_PGE, 0, PAGE_SIZE);
> + memset(absolute_pointer(EMPTY_PGE), 0, PAGE_SIZE);
> return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED));
> }
>
> @@ -253,7 +253,7 @@ void __init paging_init(void)
> free_area_init(max_zone_pfn);
>
> /* Initialize the kernel's ZERO_PGE. */
> - memset((void *)ZERO_PGE, 0, PAGE_SIZE);
> + memset(absolute_pointer(ZERO_PGE), 0, PAGE_SIZE);
> }
>
> #if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM)
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 2+ messages in thread* [PATCH] alpha: Silence -Warray-bounds warnings
@ 2022-02-02 22:18 Kees Cook
0 siblings, 0 replies; 2+ messages in thread
From: Kees Cook @ 2022-02-02 22:18 UTC (permalink / raw)
To: Richard Henderson
Cc: Kees Cook, Ivan Kokshaysky, Matt Turner, Guenter Roeck,
Arnd Bergmann, linux-kernel, linux-alpha, linux-hardening
GCC 11 (incorrectly[1]) assumes that literal values cast to (void *)
should be treated like a NULL pointer with an offset, and raises
diagnostics when doing bounds checking:
In function '__memset',
inlined from '__bad_pagetable' at arch/alpha/mm/init.c:79:2:
./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds]
37 | return __builtin_memset(s, c, n);
| ^~~~~~~~~~~~~~~~~~~~~~~~~
In function '__memset',
inlined from '__bad_page' at arch/alpha/mm/init.c:86:2:
./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds]
37 | return __builtin_memset(s, c, n);
| ^~~~~~~~~~~~~~~~~~~~~~~~~
In function '__memset',
inlined from 'paging_init' at arch/alpha/mm/init.c:256:2:
./arch/alpha/include/asm/string.h:37:32: error: '__builtin_memset' offset [0, 8191] is out of the bounds [0, 0] [-Werror=array-bounds]
37 | return __builtin_memset(s, c, n);
This has been solved in other places[2] already by using the recently
added absolute_pointer() macro. Do the same here.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
[2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/alpha/mm/init.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/alpha/mm/init.c b/arch/alpha/mm/init.c
index f6114d03357c..7511723b7669 100644
--- a/arch/alpha/mm/init.c
+++ b/arch/alpha/mm/init.c
@@ -76,14 +76,14 @@ pgd_alloc(struct mm_struct *mm)
pmd_t *
__bad_pagetable(void)
{
- memset((void *) EMPTY_PGT, 0, PAGE_SIZE);
+ memset(absolute_pointer(EMPTY_PGT), 0, PAGE_SIZE);
return (pmd_t *) EMPTY_PGT;
}
pte_t
__bad_page(void)
{
- memset((void *) EMPTY_PGE, 0, PAGE_SIZE);
+ memset(absolute_pointer(EMPTY_PGE), 0, PAGE_SIZE);
return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED));
}
@@ -253,7 +253,7 @@ void __init paging_init(void)
free_area_init(max_zone_pfn);
/* Initialize the kernel's ZERO_PGE. */
- memset((void *)ZERO_PGE, 0, PAGE_SIZE);
+ memset(absolute_pointer(ZERO_PGE), 0, PAGE_SIZE);
}
#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM)
--
2.30.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2022-02-02 23:17 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-02 23:17 [PATCH] alpha: Silence -Warray-bounds warnings Guenter Roeck
-- strict thread matches above, loose matches on Subject: below --
2022-02-02 22:18 Kees Cook
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).