Date: Thu, 29 Nov 2018 13:33:40 +0100
From: Greg KH <gregkh@linuxfoundation.org>
To: Janosch Frank <frankja@linux.ibm.com>
Cc: stable@vger.kernel.org, borntraeger@de.ibm.com
Subject: Re: [PATCH 4.9+] s390/mm: Check for valid vma before zapping in
 gmap_discard
Message-ID: <20181129123340.GH3149@kroah.com>
References: <1541666461-19279-1-git-send-email-frankja@linux.ibm.com>
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On Thu, Nov 08, 2018 at 09:41:00AM +0100, Janosch Frank wrote:
> From: Janosch Frank <frankja@de.ibm.com>
> 
> Userspace could have munmapped the area before doing unmapping from the
> gmap. This would leave us with a valid vmaddr, but an invalid vma from
> which we would try to zap memory.
> 
> Let's check before using the vma.
> 
> Fixes: 1e133ab296f3 ("s390/mm: split arch/s390/mm/pgtable.c")
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> CC: stable@vger.kernel.org # 4.6+
> ---
>  arch/s390/mm/gmap.c | 2 ++
>  1 file changed, 2 insertions(+)

Please always include the upstream git commit id so that I have a clue
as to what it is when doing the backport.

thanks,

greg k-h