[PATCH] x86/mce/dev-mcelog: Fix "make W=1" warning about strncpy

From: Tony Luck
Date: Wed May 27 2020 - 14:55:19 EST

The kbuild test robot reported this warning:

arch/x86/kernel/cpu/mce/dev-mcelog.c: In function 'dev_mcelog_init_device':
arch/x86/kernel/cpu/mce/dev-mcelog.c:346:2: warning: 'strncpy' output truncated before terminating nul copying 12 bytes from a string of the same length [-Wstringop-truncation]

This is accurate, but I don't care that the trailing NUL character isn't copied.
The string being copied is just a magic number signature so that crash dump
tools can be sure they are decoding the right blob of memory.

Change to use memcpy() instead of strncpy()

Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
arch/x86/kernel/cpu/mce/dev-mcelog.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/dev-mcelog.c b/arch/x86/kernel/cpu/mce/dev-mcelog.c
index d089567a9ce8..bcb379b2fd42 100644
--- a/arch/x86/kernel/cpu/mce/dev-mcelog.c
+++ b/arch/x86/kernel/cpu/mce/dev-mcelog.c
@@ -343,7 +343,7 @@ static __init int dev_mcelog_init_device(void)
if (!mcelog)
return -ENOMEM;

- strncpy(mcelog->signature, MCE_LOG_SIGNATURE, sizeof(mcelog->signature));
+ memcpy(mcelog->signature, MCE_LOG_SIGNATURE, sizeof(mcelog->signature));
mcelog->len = mce_log_len;
mcelog->recordlen = sizeof(struct mce);