The patch titled
Subject: kcov: avoid clang out-of-range warning
has been added to the -mm mm-nonmm-unstable branch. Its filename is
kcov-avoid-clang-out-of-range-warning.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kcov-avoid-clang-out-of-range-warning.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: kcov: avoid clang out-of-range warning
Date: Thu, 28 Mar 2024 15:30:42 +0100
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.
Link: https://lkml.kernel.org/r/20240328143051.1069575-5-arnd@xxxxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: Justin Stitt <justinstitt@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Bill Wendling <morbo@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kcov.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/kcov.c~kcov-avoid-clang-out-of-range-warning
+++ a/kernel/kcov.c
@@ -627,7 +627,8 @@ static int kcov_ioctl_locked(struct kcov
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;
_
Patches currently in -mm which might be from arnd@xxxxxxxx are
nilfs2-fix-out-of-range-warning.patch
kcov-avoid-clang-out-of-range-warning.patch
