Messages in this thread | | | From | Arnd Bergmann <> | Date | Fri, 26 Jun 2020 16:37:16 +0200 | Subject | Re: [PATCH 04/10] misc: lkdtm: bugs: At least try to use popuated variable |
| |
On Fri, Jun 26, 2020 at 3:05 PM Lee Jones <lee.jones@linaro.org> wrote: > > 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>
I think a clearer way to address this would be to add a cast to void than to actually use the variable.
Looking at the implementation, it also seems odd to use a 'const char *' as the source and a 'volatile char' as the destination, I would have expected the opposite (marking the source volatile to force the access), though I suppose the effect is the same.
Arnd
| |