Messages in this thread | | | From | Justin Stitt <> | Date | Thu, 28 Mar 2024 15:22:16 -0700 | Subject | Re: [PATCH 4/9] kcov: avoid clang out-of-range warning |
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On Thu, Mar 28, 2024 at 7:31 AM Arnd Bergmann <arnd@kernel.org> wrote: > > 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>
Reviewed-by: Justin Stitt <justinstitt@google.com>
> --- > 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 >
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