[PATCH 04/10] misc: lkdtm: bugs: At least try to use popuated variable

Lee Jones
2020-06-26T13:08:03Z

The result may not be intereresting, but not using a set variable
is bad form and causes W=1 kernel builds to complain.

Fixes the following W=1 warning(s):

drivers/misc/lkdtm/bugs.c: In function ‘lkdtm_STACK_GUARD_PAGE_LEADING’:
drivers/misc/lkdtm/bugs.c:331:25: warning: variable ‘byte’ set but not used [-Wunused-but-set-variable]
331 | volatile unsigned char byte;
| ^~~~
drivers/misc/lkdtm/bugs.c: In function ‘lkdtm_STACK_GUARD_PAGE_TRAILING’:
drivers/misc/lkdtm/bugs.c:345:25: warning: variable ‘byte’ set but not used [-Wunused-but-set-variable]
345 | volatile unsigned char byte;
| ^~~~

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/misc/lkdtm/bugs.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 736675f0a2464..4f94296fc58ad 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -334,7 +334,7 @@ void lkdtm_STACK_GUARD_PAGE_LEADING(void)

byte = *ptr;

- pr_err("FAIL: accessed page before stack!\n");
+ pr_err("FAIL: accessed page before stack! (byte: %x)\n", byte);
}

/* Test that VMAP_STACK is actually allocating with a trailing guard page */
@@ -348,7 +348,7 @@ void lkdtm_STACK_GUARD_PAGE_TRAILING(void)

byte = *ptr;

- pr_err("FAIL: accessed page after stack!\n");
+ pr_err("FAIL: accessed page after stack! (byte: %x)\n", byte);
}

void lkdtm_UNSET_SMEP(void)
--
2.25.1