linux-kernel - [PATCH 4.9 011/101] kdb: use memmove instead of overlapping memcpy

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Message-Id: <20181206143012.221175584@linuxfoundation.org>
Date:   Thu,  6 Dec 2018 15:38:10 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Jason Wessel <jason.wessel@...driver.com>
Subject: [PATCH 4.9 011/101] kdb: use memmove instead of overlapping memcpy

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@...db.de>

commit 2cf2f0d5b91fd1b06a6ae260462fc7945ea84add upstream.

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>
Signed-off-by: Jason Wessel <jason.wessel@...driver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 kernel/debug/kdb/kdb_support.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/debug/kdb/kdb_support.c
+++ b/kernel/debug/kdb/kdb_support.c
@@ -129,13 +129,13 @@ int kdbnearsym(unsigned long addr, kdb_s
 		}
 		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));
 		}