[PATCH] mm: change fault_in_pages_* to have an unsigned size parameter

From: Greg Kroah-Hartman
Date: Tue Jul 27 2021 - 07:11:47 EST


fault_in_pages_writeable() and fault_in_pages_readable() treat the size
parameter as unsigned, doing pointer math with the value, so make this
explicit and set it to be a size_t type which all callers currently
treat it as anyway.

This solves the issue where static checkers get nervous seeing pointer
arithmetic happening with a signed value.

Reported-by: Jordy Zomer <jordy@pwning.systems>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: William Kucharski <william.kucharski@xxxxxxxxxx>
Cc: "Darrick J. Wong" <djwong@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/pagemap.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index ed02aa522263..5dcf446f42e5 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -736,7 +736,7 @@ extern void add_page_wait_queue(struct page *page, wait_queue_entry_t *waiter);
/*
* Fault everything in given userspace address range in.
*/
-static inline int fault_in_pages_writeable(char __user *uaddr, int size)
+static inline int fault_in_pages_writeable(char __user *uaddr, size_t size)
{
char __user *end = uaddr + size - 1;

@@ -763,7 +763,7 @@ static inline int fault_in_pages_writeable(char __user *uaddr, int size)
return 0;
}

-static inline int fault_in_pages_readable(const char __user *uaddr, int size)
+static inline int fault_in_pages_readable(const char __user *uaddr, size_t size)
{
volatile char c;
const char __user *end = uaddr + size - 1;
--
2.32.0