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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Maor Gottlieb <maorg@mellanox.com>,
        Leon Romanovsky <leon@kernel.org>,
        Doug Ledford <dledford@redhat.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.9 048/177] IB/mlx4: Change vma from shared to private
Date:   Fri, 23 Mar 2018 10:52:56 +0100
Message-Id: <20180323094207.440173275@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Maor Gottlieb <maorg@mellanox.com>


[ Upstream commit ca37a664a8e4e9988b220988ceb4d79e3316f195 ]

Anonymous VMA (->vm_ops == NULL) cannot be shared, otherwise
it would lead to SIGBUS.

Remove the shared flags from the vma after we change it to be
anonymous.

This is easily reproduced by doing modprobe -r while running a
user-space application such as raw_ethernet_bw.

Fixes: ae184ddeca5db ('IB/mlx4_ib: Disassociate support')
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/infiniband/hw/mlx4/main.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -1182,6 +1182,8 @@ static void mlx4_ib_disassociate_ucontex
 			BUG_ON(1);
 		}
 
+		context->hw_bar_info[i].vma->vm_flags &=
+			~(VM_SHARED | VM_MAYSHARE);
 		/* context going to be destroyed, should not access ops any more */
 		context->hw_bar_info[i].vma->vm_ops = NULL;
 	}