linux-kernel - [PATCH AUTOSEL for 4.4 040/101] IB/mlx4: Change vma from shared to private

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Message-ID: <20180308050023.8548-40-alexander.levin@microsoft.com>
Date:   Thu, 8 Mar 2018 05:01:41 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     Maor Gottlieb <maorg@...lanox.com>,
        Leon Romanovsky <leon@...nel.org>,
        Doug Ledford <dledford@...hat.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.4 040/101] IB/mlx4: Change vma from shared to
 private

From: Maor Gottlieb <maorg@...lanox.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@...lanox.com>
Signed-off-by: Leon Romanovsky <leon@...nel.org>
Signed-off-by: Doug Ledford <dledford@...hat.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/infiniband/hw/mlx4/main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c
index 9119e0b3c2b8..67c4c73343d4 100644
--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -1055,6 +1055,8 @@ static void mlx4_ib_disassociate_ucontext(struct ib_ucontext *ibcontext)
 			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;
 	}
-- 
2.14.1