On Mon, Sep 14, 2026 at 07:58:23AM -0700, Paul E. McKenney wrote:
> On Mon, Sep 14, 2026 at 01:53:32PM +0000, Ricardo Ribalda wrote:
> > __typeof__() preserves every qualifier, the address space included.
> >
> > When we do __typeof(*__user *int), we are declaring a __user integer,
> > which is pretty much meaningless. A value in a register or in the stack
> > does not live in the user address space.
> >
> > This annotation did not trigger any error until a recent version of
> > smatch[1] started caring. And as a result of that now we have tens of
> > warnings like:
> >
> > drivers/media/usb/uvc/uvc_v4l2.c:1112:13: warning: incorrect type in
> > argument 2 (different address spaces)
> > drivers/media/usb/uvc/uvc_v4l2.c:1112:13: expected void const *from
> > drivers/media/usb/uvc/uvc_v4l2.c:1112:13: got unsigned int __user *
> >
> > Instead of __typeof__() use TYPEOF_UNQUAL(). It maps to
> > __typeof_unqual__() in recent compilers, so the address space annotation
> > is gone.
> >
> > [1]
> > https://github.com/error27/smatch/commit/e53027a4e816a772403baafa83c09e4a94c1cb8f
> >
> > Suggested-by: Dan Carpenter <[email protected]>
> > Link:
> > https://lore.kernel.org/r/[email protected]
> > Signed-off-by: Ricardo Ribalda <[email protected]>
>
> Queued for testing and review, thank you both!
GAH!!! I actually queued the rcu_ref one and replied to the wrong
email, apologies for my confusion. Or was it a hallucination?
You be the judge! ;-)
0a45e252da65 ("rcu: Drop the address space qualifier from the dereference
macros")
Thanx, Paul
> > ---
> > arch/x86/include/asm/uaccess.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
> > index 3a0dd3c2b233..4e576c0b9131 100644
> > --- a/arch/x86/include/asm/uaccess.h
> > +++ b/arch/x86/include/asm/uaccess.h
> > @@ -172,7 +172,7 @@ extern void __put_user_nocheck_8(void);
> > int __ret_pu; \
> > void __user *__ptr_pu; \
> > register __typeof__(*(ptr)) __val_pu asm("%"_ASM_AX); \
> > - __typeof__(*(ptr)) __x = (x); /* eval x once */ \
> > + TYPEOF_UNQUAL(*(ptr)) __x = (x); /* eval x once */ \
> > __typeof__(ptr) __ptr = (ptr); /* eval ptr once */ \
> > __chk_user_ptr(__ptr); \
> > __ptr_pu = __ptr; \
> > @@ -231,7 +231,7 @@ extern void __put_user_nocheck_8(void);
> >
> > #define __put_user_size(x, ptr, size, label)
> > \
> > do {
> > \
> > - __typeof__(*(ptr)) __x = (x); /* eval x once */ \
> > + TYPEOF_UNQUAL(*(ptr)) __x = (x); /* eval x once */ \
> > __typeof__(ptr) __ptr = (ptr); /* eval ptr once */ \
> > __chk_user_ptr(__ptr); \
> > switch (size) { \
> >
> > --
> > 2.55.0.1007.g17ff1f9808-goog
> >
>
