On Wed, Sep 07, 2022 at 04:05:56PM -0700, Kees Cook wrote: > Clang is especially sensitive about argument type matching when using > __overloaded functions (like memcmp(), etc). Help it see that function > pointers are just "void *". Avoids this error: > > arch/mips/bcm47xx/prom.c:89:8: error: no matching function for call to 'memcmp' > if (!memcmp(prom_init, prom_init + mem, 32)) > ^~~~~~ > include/linux/string.h:156:12: note: candidate function not viable: no known conversion from 'void (void)' to 'const void *' for 1st argument extern int memcmp(const void *,const void *,__kernel_size_t); > > Cc: Hauke Mehrtens <hauke@xxxxxxxxxx> > Cc: "Rafał Miłecki" <zajec5@xxxxxxxxx> > Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> > Cc: linux-mips@xxxxxxxxxxxxxxx > Cc: Nathan Chancellor <nathan@xxxxxxxxxx> > Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > Cc: llvm@xxxxxxxxxxxxxxx > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Link: https://lore.kernel.org/lkml/202209080652.sz2d68e5-lkp@xxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > arch/mips/bcm47xx/prom.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c > index ab203e66ba0d..eb5c04a24531 100644 > --- a/arch/mips/bcm47xx/prom.c > +++ b/arch/mips/bcm47xx/prom.c > @@ -86,7 +86,7 @@ static __init void prom_init_mem(void) > pr_debug("Assume 128MB RAM\n"); > break; > } > - if (!memcmp(prom_init, prom_init + mem, 32)) > + if (!memcmp((void *)prom_init, (void *)prom_init + mem, 32)) > break; > } > lowmem = mem; > -- > 2.34.1 applied to mips-next with the second memcmp(prom_init changed as well. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]
