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Date: Fri, 2 Feb 2018 09:08:40 -0600
From: Jason Wessel <jason.wessel@...driver.com>
To: Arnd Bergmann <arnd@...db.de>,
Daniel Thompson <daniel.thompson@...aro.org>
CC: Nicolas Pitre <nico@...aro.org>, Andi Kleen <ak@...ux.intel.com>,
<kgdb-bugreport@...ts.sourceforge.net>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kdb: use memmove instead of overlapping memcpy
On 02/02/2018 08:59 AM, Arnd Bergmann wrote:
> gcc discovered that the memcpy() arguments in kdbnearsym() overlap, so
> we should really use memmove(), which is defined to handle that correctly:
>
> In function 'memcpy',
> inlined from 'kdbnearsym' at /git/arm-soc/kernel/debug/kdb/kdb_support.c:132:4:
> /git/arm-soc/include/linux/string.h:353:9: error: '__builtin_memcpy' accessing 792 bytes at offsets 0 and 8 overlaps 784 bytes at offset 8 [-Werror=restrict]
> return __builtin_memcpy(p, q, size);
>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
> kernel/debug/kdb/kdb_support.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c
> index 5d8ef3a07ecd..1ad4370ccbf0 100644
> --- a/kernel/debug/kdb/kdb_support.c
> +++ b/kernel/debug/kdb/kdb_support.c
> @@ -129,13 +129,13 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
> }
> if (i >= ARRAY_SIZE(kdb_name_table)) {
> debug_kfree(kdb_name_table[0]);
> - memcpy(kdb_name_table, kdb_name_table+1,
> + memmove(kdb_name_table, kdb_name_table+1,
> sizeof(kdb_name_table[0]) *
> (ARRAY_SIZE(kdb_name_table)-1));
> } else {
> debug_kfree(knt1);
> knt1 = kdb_name_table[i];
> - memcpy(kdb_name_table+i, kdb_name_table+i+1,
> + memmove(kdb_name_table+i, kdb_name_table+i+1,
> sizeof(kdb_name_table[0]) *
> (ARRAY_SIZE(kdb_name_table)-i-1));
> }
>
That is good by me. Many thanks! Added to queue.
Reviewed-by: Jason Wessel <jason.wessel@...driver.com>
Jason.
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