Patch "drivers: char: mem: Fix wraparound check to allow mappings up to the end" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

drivers: char: mem: Fix wraparound check to allow mappings up to the end

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drivers-char-mem-fix-wraparound-check-to-allow-mappings-up-to-the-end.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Julius Werner <[email protected]>
Date: Fri, 2 Jun 2017 15:36:39 -0700
Subject: drivers: char: mem: Fix wraparound check to allow mappings up to the end

From: Julius Werner <[email protected]>

commit 32829da54d9368103a2f03269a5120aa9ee4d5da upstream.

A recent fix to /dev/mem prevents mappings from wrapping around the end of physical address space. However, the check was written in a way that also prevents a mapping reaching just up to the end of physical address space, which may be a valid use case (especially on 32-bit systems). This patch fixes it by checking the last mapped address (instead of the first address behind that) for overflow.

---
 drivers/char/mem.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -343,7 +343,7 @@ static int mmap_mem(struct file *file, s
 	phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
 
 	/* It's illegal to wrap around the end of the physical address space. */
-	if (offset + (phys_addr_t)size < offset)
+	if (offset + (phys_addr_t)size - 1 < offset)
 		return -EINVAL;
 
 	if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/drivers-char-mem-fix-wraparound-check-to-allow-mappings-up-to-the-end.patch