path: root/lib
diff options
authorGuenter Roeck <>2021-11-02 07:24:20 -0700
committerLinus Torvalds <>2021-11-03 11:41:25 -0700
commit5c4e0a21fae877a7ef89be6dcc6263ec672372b8 (patch)
treea0b78cdf3be8bcbfa5a78209370c07df19128104 /lib
parent655fedaad36c0b31a6f6cb8f469b739b2359d74f (diff)
string: uninline memcpy_and_pad
When building m68k:allmodconfig, recent versions of gcc generate the following error if the length of UTS_RELEASE is less than 8 bytes. In function 'memcpy_and_pad', inlined from 'nvmet_execute_disc_identify' at drivers/nvme/target/discovery.c:268:2: arch/m68k/include/asm/string.h:72:25: error: '__builtin_memcpy' reading 8 bytes from a region of size 7 Discussions around the problem suggest that this only happens if an architecture does not provide strlen(), if -ffreestanding is provided as compiler option, and if CONFIG_FORTIFY_SOURCE=n. All of this is the case for m68k. The exact reasons are unknown, but seem to be related to the ability of the compiler to evaluate the return value of strlen() and the resulting execution flow in memcpy_and_pad(). It would be possible to work around the problem by using sizeof(UTS_RELEASE) instead of strlen(UTS_RELEASE), but that would only postpone the problem until the function is called in a similar way. Uninline memcpy_and_pad() instead to solve the problem for good. Suggested-by: Linus Torvalds <> Reviewed-by: Geert Uytterhoeven <> Acked-by: Andy Shevchenko <> Signed-off-by: Guenter Roeck <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'lib')
1 files changed, 20 insertions, 0 deletions
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index faa9d8e4e2c5..d5d008f5b1d9 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -883,6 +883,26 @@ char *strreplace(char *s, char old, char new)
+ * memcpy_and_pad - Copy one buffer to another with padding
+ * @dest: Where to copy to
+ * @dest_len: The destination buffer size
+ * @src: Where to copy from
+ * @count: The number of bytes to copy
+ * @pad: Character to use for padding if space is left in destination.
+ */
+void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
+ int pad)
+ if (dest_len > count) {
+ memcpy(dest, src, count);
+ memset(dest + count, pad, dest_len - count);
+ } else {
+ memcpy(dest, src, dest_len);
+ }
void fortify_panic(const char *name)