lkdtm: Prevent the compiler from optimising lkdtm_CORRUPT_STACK()
At least on powerpc with GCC 6, the compiler is smart enough to optimise
lkdtm_CORRUPT_STACK() into an empty function that just returns.
If we print the buffer after we've written to it that prevents the
compiler from optimising away data and the memset().
Change-Id: I54403b905c8204ad87caacca8c86e554965cedbd
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: c55d240003ae253d3057dcf93510c9bd64bb7a09
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c
index f336206..91edd0b 100644
--- a/drivers/misc/lkdtm_bugs.c
+++ b/drivers/misc/lkdtm_bugs.c
@@ -85,7 +85,8 @@
/* Use default char array length that triggers stack protection. */
char data[8];
- memset((void *)data, 0, 64);
+ memset((void *)data, 'a', 64);
+ pr_info("Corrupted stack with '%16s'...\n", data);
}
void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)