[PATCH 4/9] kcov: avoid clang out-of-range warning

Arnd Bergmann
2024-03-28T14:31:45Z

From: Arnd Bergmann <arnd@arndb.de>

The area_size is never larger than the maximum on 64-bit architectutes:

kernel/kcov.c:634:29: error: result of comparison of constant 1152921504606846975 with expression of type '__u32' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
if (remote_arg->area_size > LONG_MAX / sizeof(unsigned long))
~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The compiler can correctly optimize the check away and the code appears
correct to me, so just add a cast to avoid the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
kernel/kcov.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/kcov.c b/kernel/kcov.c
index f9ac2e9e460f..c3124f6d5536 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -627,7 +627,8 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
mode = kcov_get_mode(remote_arg->trace_mode);
if (mode < 0)
return mode;
- if (remote_arg->area_size > LONG_MAX / sizeof(unsigned long))
+ if ((unsigned long)remote_arg->area_size >
+ LONG_MAX / sizeof(unsigned long))
return -EINVAL;
kcov->mode = mode;
t->kcov = kcov;
--
2.39.2