linux-kernel - Re: [PATCH v1 7/7] selftests/vm: anon_cow: add R/O longterm tests via gup

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Message-ID: <74adbb51-6e33-f636-8a9c-2ad87bd9007e@redhat.com>
Date:   Wed, 19 Oct 2022 14:31:15 +0200
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
        Shuah Khan <shuah@...nel.org>,
        Jason Gunthorpe <jgg@...dia.com>,
        John Hubbard <jhubbard@...dia.com>,
        Nadav Amit <namit@...are.com>, Peter Xu <peterx@...hat.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Mike Rapoport <rppt@...nel.org>,
        Christoph von Recklinghausen <crecklin@...hat.com>,
        Don Dutile <ddutile@...hat.com>
Subject: Re: [PATCH v1 7/7] selftests/vm: anon_cow: add R/O longterm tests via
 gup_test

On 27.09.22 13:01, David Hildenbrand wrote:
> Let's trigger a R/O longterm pin on three cases of R/O mapped anonymous
> pages:
> * exclusive (never shared)
> * shared (child still alive)
> * previously shared (child no longer alive)
> 
> ... and make sure that the pin is reliable: whatever we write via the page
> tables has to be observable via the pin.
> 
> Signed-off-by: David Hildenbrand <david@...hat.com>
> ---

The following on top should silence the warning on 32bit:

https://lore.kernel.org/all/202210182101.XOyPZEQV-lkp@intel.com/T/#u


diff --git a/mm/gup_test.c b/mm/gup_test.c
index 2bbfacd31f5a..57c343f2dc51 100644
--- a/mm/gup_test.c
+++ b/mm/gup_test.c
@@ -299,7 +299,8 @@ static inline int pin_longterm_test_read(unsigned long arg)
         for (i = 0; i < pin_longterm_test_nr_pages; i++) {
                 void *addr = page_to_virt(pin_longterm_test_pages[i]);
  
-               if (copy_to_user((void __user *)user_addr, addr, PAGE_SIZE))
+               if (copy_to_user((void __user *)(unsigned long)user_addr, addr,
+                                PAGE_SIZE))
                         return -EFAULT;
                 user_addr += PAGE_SIZE;
         }


-- 
Thanks,

David / dhildenb