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From: Andrea Arcangeli <aarcange@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Hugh Dickins <hughd@google.com>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Jann Horn <jannh@google.com>, Peter Xu <peterx@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Subject: [PATCH 0/1] userfaultfd: check VM_MAYWRITE was set after verifying the uffd is registered
Date: Thu,  6 Dec 2018 16:20:27 -0500	[thread overview]
Message-ID: <20181206212028.18726-1-aarcange@redhat.com> (raw)

Hello,

The juxtaposition with the other bugchecks didn't make it apparent
that the this WARN_ON was one line too soon.

An app trying to unregister a not-yet-registered range will trigger an
_harmless_ false positive WARN_ON. No real app would do that so it
went unnoticed during testing.

This should be applied on top of 29ec90660d68 ("userfaultfd:
shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas") to shut off
the false positive warning.

Thanks,
Andrea

Andrea Arcangeli (1):
  userfaultfd: check VM_MAYWRITE was set after verifying the uffd is
    registered

 fs/userfaultfd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

             reply	other threads:[~2018-12-06 21:20 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-06 21:20 Andrea Arcangeli [this message]
2018-12-06 21:20 ` [PATCH 1/1] " Andrea Arcangeli
2018-12-06 21:32   ` Mike Rapoport
2018-12-06 22:07   ` Hugh Dickins
2018-12-07  3:43   ` Peter Xu

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