Re: [PATCH v1 7/7] selftests/vm: anon_cow: add R/O longterm tests via gup_test

From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	Shuah Khan <shuah@kernel.org>, Jason Gunthorpe <jgg@nvidia.com>,
	John Hubbard <jhubbard@nvidia.com>, Nadav Amit <namit@vmware.com>,
	Peter Xu <peterx@redhat.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
	Christoph von Recklinghausen <crecklin@redhat.com>,
	Don Dutile <ddutile@redhat.com>
Subject: Re: [PATCH v1 7/7] selftests/vm: anon_cow: add R/O longterm tests via gup_test
Date: Wed, 19 Oct 2022 14:33:17 +0200	[thread overview]
Message-ID: <c1bcb281-c4ef-3b7d-f24d-82569602939b@redhat.com> (raw)
In-Reply-To: <74adbb51-6e33-f636-8a9c-2ad87bd9007e@redhat.com>

On 19.10.22 14:31, David Hildenbrand wrote:
> 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@redhat.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;
>           }
> 
> 

Ehm, wrong patch, it actually belongs into #6/7

https://lkml.kernel.org/r/20220927110120.106906-7-david@redhat.com

@Andrew, if your confused, I can just resend the whole thing.

-- 
Thanks,

David / dhildenb