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From:   Arnd Bergmann <arnd@arndb.de>
To:     Jason Wessel <jason.wessel@windriver.com>,
        Daniel Thompson <daniel.thompson@linaro.org>
Cc:     Nicolas Pitre <nico@linaro.org>, Andi Kleen <ak@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: [PATCH] kdb: use memmove instead of overlapping memcpy
Date:   Fri,  2 Feb 2018 15:59:40 +0100
Message-Id: <20180202145952.285505-1-arnd@arndb.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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@arndb.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));
 		}
-- 
2.9.0