From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45450 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752731AbeCWKPA (ORCPT ); Fri, 23 Mar 2018 06:15:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maor Gottlieb , Leon Romanovsky , Doug Ledford , Sasha Levin Subject: [PATCH 4.4 34/97] IB/mlx4: Take write semaphore when changing the vma struct Date: Fri, 23 Mar 2018 10:54:21 +0100 Message-Id: <20180323094159.597716749@linuxfoundation.org> In-Reply-To: <20180323094157.535925724@linuxfoundation.org> References: <20180323094157.535925724@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maor Gottlieb [ Upstream commit 22c3653d04bd0c67b75e99d85e0c0bdf83947df5 ] When the driver disassociate user context, it changes the vma to anonymous by setting the vm_ops to null and zap the vma ptes. In order to avoid race in the kernel, we need to take write lock before we change the vma entries. Fixes: ae184ddeca5db ('IB/mlx4_ib: Disassociate support') Signed-off-by: Maor Gottlieb Signed-off-by: Leon Romanovsky Signed-off-by: Doug Ledford Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/mlx4/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/infiniband/hw/mlx4/main.c +++ b/drivers/infiniband/hw/mlx4/main.c @@ -1041,7 +1041,7 @@ static void mlx4_ib_disassociate_ucontex /* need to protect from a race on closing the vma as part of * mlx4_ib_vma_close(). */ - down_read(&owning_mm->mmap_sem); + down_write(&owning_mm->mmap_sem); for (i = 0; i < HW_BAR_COUNT; i++) { vma = context->hw_bar_info[i].vma; if (!vma) @@ -1059,7 +1059,7 @@ static void mlx4_ib_disassociate_ucontex context->hw_bar_info[i].vma->vm_ops = NULL; } - up_read(&owning_mm->mmap_sem); + up_write(&owning_mm->mmap_sem); mmput(owning_mm); put_task_struct(owning_process); }