Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934032AbdC3PWs (ORCPT ); Thu, 30 Mar 2017 11:22:48 -0400 Received: from forwardcorp1h.cmail.yandex.net ([87.250.230.216]:38515 "EHLO forwardcorp1h.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933048AbdC3PWq (ORCPT ); Thu, 30 Mar 2017 11:22:46 -0400 X-Greylist: delayed 496 seconds by postgrey-1.27 at vger.kernel.org; Thu, 30 Mar 2017 11:22:45 EDT Authentication-Results: mxbackcorp1g.mail.yandex.net; dkim=pass header.i=@yandex-team.ru X-Yandex-Sender-Uid: 1120000000007938 From: kmeaw@yandex-team.ru To: linux-kernel , dm-devel@redhat.com, linux-raid@vger.kernel.org Cc: agk@redhat.com, shli@kernel.org, =?utf-8?B?0JDQvdC00YDQtdC5INCh0LzQtdGC0LDQvdC40L0=?= Subject: [PATCH][RFC] dm raid: Fix NULL pointer dereference for raid1 without bitmap MIME-Version: 1.0 Message-Id: <101041490886866@webcorp01f.yandex-team.ru> X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Thu, 30 Mar 2017 18:14:26 +0300 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=utf-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3741 Lines: 78 From: Dmitry Bilunov 4257e08 introduces a bitmap resize call during preresume phase. User can create a DM device with "raid" target configured as raid1 with no metadata devices to hold superblock/bitmap info. It can be achieved using the following sequence: truncate -s 32M /dev/shm/raid-test LOOP=$(losetup --show -f /dev/shm/raid-test) dmsetup create raid-test-linear0 --table "0 1024 linear $LOOP 0" dmsetup create raid-test-linear1 --table "0 1024 linear $LOOP 1024" dmsetup create raid-test --table "0 1024 raid raid1 1 2048 2 - /dev/mapper/raid-test-linear0 - /dev/mapper/raid-test-linear1" It results in Killed [ 4029.110216] device-mapper: raid: Ignoring chunk size parameter for RAID 1 [ 4029.110217] device-mapper: raid: Choosing default region size of 4MiB [ 4029.111349] md/raid1:mdX: active with 2 out of 2 mirrors [ 4029.114770] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 [ 4029.114802] IP: bitmap_resize+0x25/0x7c0 [md_mod] [ 4029.114816] PGD 0 … [ 4029.115059] Hardware name: Aquarius Pro P30 S85 BUY-866/B85M-E, BIOS 2304 05/25/2015 [ 4029.115079] task: ffff88015cc29a80 task.stack: ffffc90001a5c000 [ 4029.115097] RIP: 0010:bitmap_resize+0x25/0x7c0 [md_mod] [ 4029.115112] RSP: 0018:ffffc90001a5fb68 EFLAGS: 00010246 [ 4029.115127] RAX: 0000000000000005 RBX: 0000000000000000 RCX: 0000000000000000 [ 4029.115146] RDX: 0000000000000000 RSI: 0000000000000400 RDI: 0000000000000000 [ 4029.115166] RBP: ffffc90001a5fc28 R08: 0000000800000000 R09: 00000008ffffffff [ 4029.115185] R10: ffffea0005661600 R11: ffff88015cc29a80 R12: ffff88021231f058 [ 4029.115204] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 4029.115223] FS: 00007fe73a6b4740(0000) GS:ffff88021ea80000(0000) knlGS:0000000000000000 [ 4029.115245] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4029.115261] CR2: 0000000000000030 CR3: 0000000159a74000 CR4: 00000000001426e0 [ 4029.115281] Call Trace: [ 4029.115291] ? raid_iterate_devices+0x63/0x80 [dm_raid] [ 4029.115309] ? dm_table_all_devices_attribute.isra.23+0x41/0x70 [dm_mod] [ 4029.115329] ? dm_table_set_restrictions+0x225/0x2d0 [dm_mod] [ 4029.115346] raid_preresume+0x81/0x2e0 [dm_raid] [ 4029.115361] dm_table_resume_targets+0x47/0xe0 [dm_mod] [ 4029.115378] dm_resume+0xa8/0xd0 [dm_mod] [ 4029.115391] dev_suspend+0x123/0x250 [dm_mod] [ 4029.115405] ? table_load+0x350/0x350 [dm_mod] [ 4029.115419] ctl_ioctl+0x1c2/0x490 [dm_mod] [ 4029.115433] dm_ctl_ioctl+0xe/0x20 [dm_mod] [ 4029.115447] do_vfs_ioctl+0x8d/0x5a0 [ 4029.115459] ? ____fput+0x9/0x10 [ 4029.115470] ? task_work_run+0x79/0xa0 [ 4029.115481] SyS_ioctl+0x3c/0x70 [ 4029.115493] entry_SYSCALL_64_fastpath+0x13/0x94 Function raid_preresume takes an assumption that raid_set has a bitmap enabled. Call to bitmap_load(&rs->md) inside __load_dirty_region_bitmap would return 0 even if there is no bitmap present. This patch avoids resizing an absent bitmap. Signed-off-by: Dmitry Bilunov Signed-off-by: Andrey Smetanin --- drivers/md/dm-raid.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index f8564d63..67a5405e 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -3727,6 +3727,7 @@ static int raid_preresume(struct dm_target *ti) /* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) */ if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && + mddev->bitmap && mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)) { r = bitmap_resize(mddev->bitmap, mddev->dev_sectors, to_bytes(rs->requested_bitmap_chunk_sectors), 0); -- 2.12.2