On Sat, Feb 25, 2017 at 1:35 AM, Dmitry V. Levin <l...@altlinux.org> wrote: > On Fri, Feb 24, 2017 at 05:35:33PM +0300, Alexey Dobriyan wrote: >> On Thu, Feb 23, 2017 at 02:44:31PM -0800, a...@linux-foundation.org wrote: >> > /usr/include/linux/sysctl.h:38:2: error: unknown type name 'size_t' >> > size_t *oldlenp; >> > /usr/include/linux/sysctl.h:40:2: error: unknown type name 'size_t' >> > size_t newlen; >> >> > --- >> > a/include/uapi/linux/sysctl.h~uapi-fix-linux-sysctlh-userspace-compilation-errors >> > +++ a/include/uapi/linux/sysctl.h >> > @@ -26,6 +26,10 @@ >> > #include <linux/types.h> >> > #include <linux/compiler.h> >> > >> > +#ifndef __KERNEL__ >> > +#include <stddef.h> /* For size_t. */ >> > +#endif >> >> There is __kernel_size_t for cases like this. > > No, __kernel_size_t is not for cases like this because size_t differs > from __kernel_size_t on x32 and mips n32. > > Fortunately, there is no sysctl syscall entry on x32, but on mips m32 > it is there with number 6152, implemented using compat_sys_sysctl. > The latter operates with argument of type struct compat_sysctl_args* > where newlen is of type compat_size_t. > > If you change it from size_t to __kernel_size_t, you'll break mips n32.
You're gluing kernel interface to an userspace header which kernel doesn't control. How can this fix anything?