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:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     Dmitry Monakhov <dmonakhov@openvz.org>, Jens Axboe <axboe@fb.com>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.4 120/167] bio-integrity: Do not allocate
 integrity context for bio w/o data
Thread-Topic: [PATCH AUTOSEL for 4.4 120/167] bio-integrity: Do not allocate
 integrity context for bio w/o data
Thread-Index: AQHTv5xvVv4PljaEE0O6Cd1zF0nU4A==
Date:   Mon, 19 Mar 2018 16:07:52 +0000
Message-ID: <20180319160513.16384-120-alexander.levin@microsoft.com>
References: <20180319160513.16384-1-alexander.levin@microsoft.com>
In-Reply-To: <20180319160513.16384-1-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: 9711a63b-6a0f-4107-9465-08d58db3dfae
X-MS-Exchange-CrossTenant-originalarrivaltime: 19 Mar 2018 16:07:52.6619
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB0919
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: Dmitry Monakhov <dmonakhov@openvz.org>

[ Upstream commit 3116a23bb30272d74ea81baf5d0ee23f602dd15b ]

If bio has no data, such as ones from blkdev_issue_flush(),
then we have nothing to protect.

This patch prevent bugon like follows:

kfree_debugcheck: out of range ptr ac1fa1d106742a5ah
kernel BUG at mm/slab.c:2773!
invalid opcode: 0000 [#1] SMP
Modules linked in: bcache
CPU: 0 PID: 4428 Comm: xfs_io Tainted: G        W       4.11.0-rc4-ext4-000=
41-g2ef0043-dirty #43
Hardware name: Virtuozzo KVM, BIOS seabios-1.7.5-11.vz7.4 04/01/2014
task: ffff880137786440 task.stack: ffffc90000ba8000
RIP: 0010:kfree_debugcheck+0x25/0x2a
RSP: 0018:ffffc90000babde0 EFLAGS: 00010082
RAX: 0000000000000034 RBX: ac1fa1d106742a5a RCX: 0000000000000007
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88013f3ccb40
RBP: ffffc90000babde8 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000fcb76420 R11: 00000000725172ed R12: 0000000000000282
R13: ffffffff8150e766 R14: ffff88013a145e00 R15: 0000000000000001
FS:  00007fb09384bf40(0000) GS:ffff88013f200000(0000) knlGS:000000000000000=
0
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd0172f9e40 CR3: 0000000137fa9000 CR4: 00000000000006f0
Call Trace:
 kfree+0xc8/0x1b3
 bio_integrity_free+0xc3/0x16b
 bio_free+0x25/0x66
 bio_put+0x14/0x26
 blkdev_issue_flush+0x7a/0x85
 blkdev_fsync+0x35/0x42
 vfs_fsync_range+0x8e/0x9f
 vfs_fsync+0x1c/0x1e
 do_fsync+0x31/0x4a
 SyS_fsync+0x10/0x14
 entry_SYSCALL_64_fastpath+0x1f/0xc2

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 block/bio-integrity.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index f6325d573c10..6e091ccadcd4 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -175,6 +175,9 @@ bool bio_integrity_enabled(struct bio *bio)
 	if (!bio_is_rw(bio))
 		return false;
=20
+	if (!bio_sectors(bio))
+		return false;
+
 	/* Already protected? */
 	if (bio_integrity(bio))
 		return false;
--=20
2.14.1