Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Geert Uytterhoeven <geert+renesas@glider.be>,
        Joerg Roedel <jroedel@suse.de>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.14 74/89] iommu/ipmmu-vmsa: Fix allocation in atomic
 context
Thread-Topic: [PATCH AUTOSEL 4.14 74/89] iommu/ipmmu-vmsa: Fix allocation in
 atomic context
Thread-Index: AQHUQr3tafKdFKxyukOt8FnqSQcHyg==
Date:   Sun, 2 Sep 2018 13:07:40 +0000
Message-ID: <20180902064918.183387-74-alexander.levin@microsoft.com>
References: <20180902064918.183387-1-alexander.levin@microsoft.com>
In-Reply-To: <20180902064918.183387-1-alexander.levin@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 1b9de22e-0a01-4815-c190-08d610d52181
X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Sep 2018 13:07:40.2015
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0149
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Geert Uytterhoeven <geert+renesas@glider.be>

[ Upstream commit 46583e8c48c5a094ba28060615b3a7c8c576690f ]

When attaching a device to an IOMMU group with
CONFIG_DEBUG_ATOMIC_SLEEP=3Dy:

    BUG: sleeping function called from invalid context at mm/slab.h:421
    in_atomic(): 1, irqs_disabled(): 128, pid: 61, name: kworker/1:1
    ...
    Call trace:
     ...
     arm_lpae_alloc_pgtable+0x114/0x184
     arm_64_lpae_alloc_pgtable_s1+0x2c/0x128
     arm_32_lpae_alloc_pgtable_s1+0x40/0x6c
     alloc_io_pgtable_ops+0x60/0x88
     ipmmu_attach_device+0x140/0x334

ipmmu_attach_device() takes a spinlock, while arm_lpae_alloc_pgtable()
allocates memory using GFP_KERNEL.  Originally, the ipmmu-vmsa driver
had its own custom page table allocation implementation using
GFP_ATOMIC, hence the spinlock was fine.

Fix this by replacing the spinlock by a mutex, like the arm-smmu driver
does.

Fixes: f20ed39f53145e45 ("iommu/ipmmu-vmsa: Use the ARM LPAE page table all=
ocator")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/iommu/ipmmu-vmsa.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 195d6e93ac71..5d0ba5f644c4 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -54,7 +54,7 @@ struct ipmmu_vmsa_domain {
 	struct io_pgtable_ops *iop;
=20
 	unsigned int context_id;
-	spinlock_t lock;			/* Protects mappings */
+	struct mutex mutex;			/* Protects mappings */
 };
=20
 struct ipmmu_vmsa_iommu_priv {
@@ -523,7 +523,7 @@ static struct iommu_domain *__ipmmu_domain_alloc(unsign=
ed type)
 	if (!domain)
 		return NULL;
=20
-	spin_lock_init(&domain->lock);
+	mutex_init(&domain->mutex);
=20
 	return &domain->io_domain;
 }
@@ -548,7 +548,6 @@ static int ipmmu_attach_device(struct iommu_domain *io_=
domain,
 	struct iommu_fwspec *fwspec =3D dev->iommu_fwspec;
 	struct ipmmu_vmsa_device *mmu =3D priv->mmu;
 	struct ipmmu_vmsa_domain *domain =3D to_vmsa_domain(io_domain);
-	unsigned long flags;
 	unsigned int i;
 	int ret =3D 0;
=20
@@ -557,7 +556,7 @@ static int ipmmu_attach_device(struct iommu_domain *io_=
domain,
 		return -ENXIO;
 	}
=20
-	spin_lock_irqsave(&domain->lock, flags);
+	mutex_lock(&domain->mutex);
=20
 	if (!domain->mmu) {
 		/* The domain hasn't been used yet, initialize it. */
@@ -574,7 +573,7 @@ static int ipmmu_attach_device(struct iommu_domain *io_=
domain,
 	} else
 		dev_info(dev, "Reusing IPMMU context %u\n", domain->context_id);
=20
-	spin_unlock_irqrestore(&domain->lock, flags);
+	mutex_unlock(&domain->mutex);
=20
 	if (ret < 0)
 		return ret;
--=20
2.17.1