Re: [PATCH 5.19 0246/1157] usercopy: use unsigned long instead of uintptr_t

[Matthew Wilcox]

On Mon, Aug 15, 2022 at 07:53:22PM +0200, Greg Kroah-Hartman wrote:
> From: Jason A. Donenfeld <Jason@xxxxxxxxx>
> 
> [ Upstream commit 170b2c350cfcb6f74074e44dd9f916787546db0d ]
> 
> A recent commit factored out a series of annoying (unsigned long) casts
> into a single variable declaration, but made the pointer type a
> `uintptr_t` rather than the usual `unsigned long`. This patch changes it
> to be the integer type more typically used by the kernel to represent
> addresses.
> 
> Fixes: 35fb9ae4aa2e ("usercopy: Cast pointer to an integer once")

Not sure why this needs to be backported?

> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Cc: Uladzislau Rezki <urezki@xxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Joe Perches <joe@xxxxxxxxxxx>
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20220616143617.449094-1-Jason@xxxxxxxxx
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
>  mm/usercopy.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/usercopy.c b/mm/usercopy.c
> index 4e1da708699b..c1ee15a98633 100644
> --- a/mm/usercopy.c
> +++ b/mm/usercopy.c
> @@ -161,7 +161,7 @@ static inline void check_bogus_address(const unsigned long ptr, unsigned long n,
>  static inline void check_heap_object(const void *ptr, unsigned long n,
>  				     bool to_user)
>  {
> -	uintptr_t addr = (uintptr_t)ptr;
> +	unsigned long addr = (unsigned long)ptr;
>  	unsigned long offset;
>  	struct folio *folio;
>  
> -- 
> 2.35.1
> 
> 
>