On Mon, 25 Jan 2021, Jarkko Sakkinen wrote:

> On Sat, Jan 23, 2021 at 05:50:31AM -0500, Mikulas Patocka wrote:
> > This patch fixes a warning:
> > arch/x86/entry/vdso/vdso2c.h:38:52: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘size_t’ {aka ‘unsigned int’} [-Wformat=]
> > when compiling the kernel with x32 compiler.
> > 
> > The reason for the warning is that in x32 mode, size_t is defined as
> > unsigned, not unsigned long.
> > 
> > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
> > Fixes: 8382c668ce4f ("x86/vdso: Add support for exception fixup in vDSO functions")
> 
> So... Why not %zu?
> 
> /Jarkko

You can use %zu - it doesn't matter, size_t has the same size as unsigned 
long on all supported architectures.

Mikulas