{"action":"created","issue":{"url":"https://api.github.com/repos/zfsonlinux/zfs/issues/4694","repository_url":"https://api.github.com/repos/zfsonlinux/zfs","labels_url":"https://api.github.com/repos/zfsonlinux/zfs/issues/4694/labels{/name}","comments_url":"https://api.github.com/repos/zfsonlinux/zfs/issues/4694/comments","events_url":"https://api.github.com/repos/zfsonlinux/zfs/issues/4694/events","html_url":"https://github.com/zfsonlinux/zfs/issues/4694","id":156524607,"number":4694,"title":"self-hosting hang/deadlock (zpool on zvol)","user":{"login":"nigoroll","id":1528104,"avatar_url":"https://avatars.githubusercontent.com/u/1528104?v=3","gravatar_id":"","url":"https://api.github.com/users/nigoroll","html_url":"https://github.com/nigoroll","followers_url":"https://api.github.com/users/nigoroll/followers","following_url":"https://api.github.com/users/nigoroll/following{/other_user}","gists_url":"https://api.github.com/users/nigoroll/gists{/gist_id}","starred_url":"https://api.github.com/users/nigoroll/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nigoroll/subscriptions","organizations_url":"https://api.github.com/users/nigoroll/orgs","repos_url":"https://api.github.com/users/nigoroll/repos","events_url":"https://api.github.com/users/nigoroll/events{/privacy}","received_events_url":"https://api.github.com/users/nigoroll/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2016-05-24T14:36:45Z","updated_at":"2016-05-24T22:34:25Z","closed_at":null,"body":"On solaris-ish systems, zfs is capabable of self hosting / creating zpools within other zpools\r\n\r\nFor me, this leads to a hang/deadlock:\r\n\r\n```\r\nzfs create -ps -V 1t pool/t/vol\r\nzpool create newpool /dev/zvol/pool/t/vol &\r\nsleep 5;\r\nzpool list\r\n```\r\n\r\n* `debian 8.4`\r\n* `Linux haggis 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2 (2016-04-08) x86_64 GNU/Linux`\r\n* `zfs-dkms 0.6.5.7-8-jessie`\r\n\r\n```\r\nMay 24 16:07:53 haggis kernel: [23285.684420] systemd-udevd   D ffff880468c9d908     0   371      1 0x00000000\r\nMay 24 16:07:53 haggis kernel: [23285.684423]  ffff880468c9d4b0 0000000000000086 0000000000012f00 ffff88046c06bfd8\r\nMay 24 16:07:53 haggis kernel: [23285.684425]  0000000000012f00 ffff880468c9d4b0 ffffffffa0d7cb20 ffff88046c06ba90\r\nMay 24 16:07:53 haggis kernel: [23285.684427]  ffffffffa0d7cb24 ffff880468c9d4b0 00000000ffffffff ffffffffa0d7cb28\r\nMay 24 16:07:53 haggis kernel: [23285.684428] Call Trace:\r\nMay 24 16:07:53 haggis kernel: [23285.684440]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:07:53 haggis kernel: [23285.684442]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:07:53 haggis kernel: [23285.684445]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:07:53 haggis kernel: [23285.684465]  [<ffffffffa0bf4e6e>] ? spa_open_common+0x4e/0x460 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684470]  [<ffffffffa0b622ef>] ? tsd_hash_dtor+0x6f/0x80 [spl]\r\nMay 24 16:07:53 haggis kernel: [23285.684483]  [<ffffffffa0bd860e>] ? dsl_pool_hold+0x1e/0x50 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684494]  [<ffffffffa0bb5842>] ? dmu_objset_hold+0x22/0xb0 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684505]  [<ffffffffa0bd8d9e>] ? dsl_prop_get+0x2e/0x80 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684517]  [<ffffffffa0c54a8a>] ? zvol_open+0x15a/0x290 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684521]  [<ffffffff811dd43c>] ? __blkdev_get+0xcc/0x480\r\nMay 24 16:07:53 haggis kernel: [23285.684523]  [<ffffffff811ddb40>] ? blkdev_get_by_dev+0x40/0x40\r\nMay 24 16:07:53 haggis kernel: [23285.684524]  [<ffffffff811dd9a6>] ? blkdev_get+0x1b6/0x310\r\nMay 24 16:07:53 haggis kernel: [23285.684526]  [<ffffffff811ddb40>] ? blkdev_get_by_dev+0x40/0x40\r\nMay 24 16:07:53 haggis kernel: [23285.684529]  [<ffffffff811a62a2>] ? do_dentry_open+0x1f2/0x330\r\nMay 24 16:07:53 haggis kernel: [23285.684531]  [<ffffffff811a65ad>] ? finish_open+0x2d/0x40\r\nMay 24 16:07:53 haggis kernel: [23285.684533]  [<ffffffff811b72ca>] ? do_last+0xaaa/0x1200\r\nMay 24 16:07:53 haggis kernel: [23285.684534]  [<ffffffff811b38a6>] ? link_path_walk+0x286/0x8a0\r\nMay 24 16:07:53 haggis kernel: [23285.684536]  [<ffffffff811b7adb>] ? path_openat+0xbb/0x680\r\nMay 24 16:07:53 haggis kernel: [23285.684538]  [<ffffffff8117abb5>] ? free_pages_and_swap_cache+0x95/0xb0\r\nMay 24 16:07:53 haggis kernel: [23285.684539]  [<ffffffff811b884a>] ? do_filp_open+0x3a/0x90\r\nMay 24 16:07:53 haggis kernel: [23285.684542]  [<ffffffff811c48ac>] ? __alloc_fd+0x7c/0x120\r\nMay 24 16:07:53 haggis kernel: [23285.684544]  [<ffffffff811a7ae9>] ? do_sys_open+0x129/0x220\r\nMay 24 16:07:53 haggis kernel: [23285.684546]  [<ffffffff81514a0d>] ? system_call_fast_compare_end+0x10/0x15\r\nMay 24 16:07:53 haggis kernel: [23285.684710] qemu-system-x86 D ffff88044ef746e8     0 15748      1 0x00000000\r\nMay 24 16:07:53 haggis kernel: [23285.684712]  ffff88044ef74290 0000000000000082 0000000000012f00 ffff8803d055bfd8\r\nMay 24 16:07:53 haggis kernel: [23285.684713]  0000000000012f00 ffff88044ef74290 ffffffffa0e00ce0 ffff8803d055be58\r\nMay 24 16:07:53 haggis kernel: [23285.684715]  ffffffffa0e00ce4 ffff88044ef74290 00000000ffffffff ffffffffa0e00ce8\r\nMay 24 16:07:53 haggis kernel: [23285.684716] Call Trace:\r\nMay 24 16:07:53 haggis kernel: [23285.684720]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:07:53 haggis kernel: [23285.684722]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:07:53 haggis kernel: [23285.684724]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:07:53 haggis kernel: [23285.684737]  [<ffffffffa0c55d36>] ? zvol_release+0x36/0x90 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684739]  [<ffffffff811dd32d>] ? __blkdev_put+0x15d/0x1a0\r\nMay 24 16:07:53 haggis kernel: [23285.684741]  [<ffffffff811ddd81>] ? blkdev_close+0x21/0x30\r\nMay 24 16:07:53 haggis kernel: [23285.684743]  [<ffffffff811aa1ea>] ? __fput+0xca/0x1d0\r\nMay 24 16:07:53 haggis kernel: [23285.684745]  [<ffffffff810852dc>] ? task_work_run+0x8c/0xb0\r\nMay 24 16:07:53 haggis kernel: [23285.684747]  [<ffffffff81012e99>] ? do_notify_resume+0x69/0xa0\r\nMay 24 16:07:53 haggis kernel: [23285.684749]  [<ffffffff81514cca>] ? int_signal+0x12/0x17\r\nMay 24 16:07:53 haggis kernel: [23285.684755] zpool           D ffff8802865d70b8     0 15932  15869 0x00000004\r\nMay 24 16:07:53 haggis kernel: [23285.684756]  ffff8802865d6c60 0000000000000082 0000000000012f00 ffff88037bcbbfd8\r\nMay 24 16:07:53 haggis kernel: [23285.684758]  0000000000012f00 ffff8802865d6c60 ffff8803e4930a98 ffff88037bcbbb28\r\nMay 24 16:07:53 haggis kernel: [23285.684759]  ffff8803e4930a9c ffff8802865d6c60 00000000ffffffff ffff8803e4930aa0\r\nMay 24 16:07:53 haggis kernel: [23285.684761] Call Trace:\r\nMay 24 16:07:53 haggis kernel: [23285.684762]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:07:53 haggis kernel: [23285.684764]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:07:53 haggis kernel: [23285.684767]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:07:53 haggis kernel: [23285.684768]  [<ffffffff811dd3d3>] ? __blkdev_get+0x63/0x480\r\nMay 24 16:07:53 haggis kernel: [23285.684770]  [<ffffffff811dd9fb>] ? blkdev_get+0x20b/0x310\r\nMay 24 16:07:53 haggis kernel: [23285.684772]  [<ffffffff811be3df>] ? dput+0x1f/0x170\r\nMay 24 16:07:53 haggis kernel: [23285.684774]  [<ffffffff811ddd24>] ? blkdev_get_by_path+0x54/0x90\r\nMay 24 16:07:53 haggis kernel: [23285.684786]  [<ffffffffa0c0aad5>] ? vdev_disk_open+0x355/0x3c0 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684798]  [<ffffffffa0c07cd8>] ? vdev_open+0xe8/0x500 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684810]  [<ffffffffa0c55dad>] ? zvol_is_zvol+0x1d/0x40 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684820]  [<ffffffffa0c08144>] ? vdev_open_children+0x54/0x170 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684831]  [<ffffffffa0c11853>] ? vdev_root_open+0x43/0xe0 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684840]  [<ffffffffa0c07cd8>] ? vdev_open+0xe8/0x500 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684849]  [<ffffffffa0c082cd>] ? vdev_create+0x1d/0xa0 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684852]  [<ffffffffa0a0313e>] ? zfs_allocatable_devs+0x5e/0x80 [zcommon]\r\nMay 24 16:07:53 haggis kernel: [23285.684865]  [<ffffffffa0bf5f3f>] ? spa_create+0x36f/0x9a0 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684876]  [<ffffffffa0c27309>] ? zfs_fill_zplprops_impl+0x1d9/0x380 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684886]  [<ffffffffa0c2b3a4>] ? zfs_ioc_pool_create+0x144/0x260 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684897]  [<ffffffffa0c29669>] ? zfsdev_ioctl+0x4a9/0x4e0 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684898]  [<ffffffff811bacdf>] ? do_vfs_ioctl+0x2cf/0x4b0\r\nMay 24 16:07:53 haggis kernel: [23285.684900]  [<ffffffff811baf41>] ? SyS_ioctl+0x81/0xa0\r\nMay 24 16:07:53 haggis kernel: [23285.684902]  [<ffffffff81516a28>] ? page_fault+0x28/0x30\r\nMay 24 16:07:53 haggis kernel: [23285.684904]  [<ffffffff81514a0d>] ? system_call_fast_compare_end+0x10/0x15\r\nMay 24 16:07:53 haggis kernel: [23285.684936] zpool           D ffff8803a5306568     0 16377  15894 0x00000000\r\nMay 24 16:07:53 haggis kernel: [23285.684938]  ffff8803a5306110 0000000000000082 0000000000012f00 ffff88037de3ffd8\r\nMay 24 16:07:53 haggis kernel: [23285.684939]  0000000000012f00 ffff8803a5306110 ffffffffa0d7cb20 ffff88037de3fe28\r\nMay 24 16:07:53 haggis kernel: [23285.684941]  ffffffffa0d7cb24 ffff8803a5306110 00000000ffffffff ffffffffa0d7cb28\r\nMay 24 16:07:53 haggis kernel: [23285.684942] Call Trace:\r\nMay 24 16:07:53 haggis kernel: [23285.684945]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:07:53 haggis kernel: [23285.684946]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:07:53 haggis kernel: [23285.684949]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:07:53 haggis kernel: [23285.684961]  [<ffffffffa0bf94f9>] ? spa_all_configs+0x49/0x180 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684971]  [<ffffffffa0c26906>] ? zfs_ioc_pool_configs+0x16/0x40 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684981]  [<ffffffffa0c29669>] ? zfsdev_ioctl+0x4a9/0x4e0 [zfs]\r\nMay 24 16:07:53 haggis kernel: [23285.684983]  [<ffffffff811bacdf>] ? do_vfs_ioctl+0x2cf/0x4b0\r\nMay 24 16:07:53 haggis kernel: [23285.684984]  [<ffffffff811baf41>] ? SyS_ioctl+0x81/0xa0\r\nMay 24 16:07:53 haggis kernel: [23285.684985]  [<ffffffff81516a28>] ? page_fault+0x28/0x30\r\nMay 24 16:07:53 haggis kernel: [23285.684987]  [<ffffffff81514a0d>] ? system_call_fast_compare_end+0x10/0x15\r\nMay 24 16:09:53 haggis kernel: [23405.713235] systemd-udevd   D ffff880468c9d908     0   371      1 0x00000000\r\nMay 24 16:09:53 haggis kernel: [23405.713244]  ffff880468c9d4b0 0000000000000086 0000000000012f00 ffff88046c06bfd8\r\nMay 24 16:09:53 haggis kernel: [23405.713250]  0000000000012f00 ffff880468c9d4b0 ffffffffa0d7cb20 ffff88046c06ba90\r\nMay 24 16:09:53 haggis kernel: [23405.713256]  ffffffffa0d7cb24 ffff880468c9d4b0 00000000ffffffff ffffffffa0d7cb28\r\nMay 24 16:09:53 haggis kernel: [23405.713262] Call Trace:\r\nMay 24 16:09:53 haggis kernel: [23405.713290]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:09:53 haggis kernel: [23405.713298]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:09:53 haggis kernel: [23405.713308]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:09:53 haggis kernel: [23405.713375]  [<ffffffffa0bf4e6e>] ? spa_open_common+0x4e/0x460 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.713391]  [<ffffffffa0b622ef>] ? tsd_hash_dtor+0x6f/0x80 [spl]\r\nMay 24 16:09:53 haggis kernel: [23405.713441]  [<ffffffffa0bd860e>] ? dsl_pool_hold+0x1e/0x50 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.713479]  [<ffffffffa0bb5842>] ? dmu_objset_hold+0x22/0xb0 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.713522]  [<ffffffffa0bd8d9e>] ? dsl_prop_get+0x2e/0x80 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.713566]  [<ffffffffa0c54a8a>] ? zvol_open+0x15a/0x290 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.713580]  [<ffffffff811dd43c>] ? __blkdev_get+0xcc/0x480\r\nMay 24 16:09:53 haggis kernel: [23405.713587]  [<ffffffff811ddb40>] ? blkdev_get_by_dev+0x40/0x40\r\nMay 24 16:09:53 haggis kernel: [23405.713594]  [<ffffffff811dd9a6>] ? blkdev_get+0x1b6/0x310\r\nMay 24 16:09:53 haggis kernel: [23405.713601]  [<ffffffff811ddb40>] ? blkdev_get_by_dev+0x40/0x40\r\nMay 24 16:09:53 haggis kernel: [23405.713609]  [<ffffffff811a62a2>] ? do_dentry_open+0x1f2/0x330\r\nMay 24 16:09:53 haggis kernel: [23405.713616]  [<ffffffff811a65ad>] ? finish_open+0x2d/0x40\r\nMay 24 16:09:53 haggis kernel: [23405.713621]  [<ffffffff811b72ca>] ? do_last+0xaaa/0x1200\r\nMay 24 16:09:53 haggis kernel: [23405.713626]  [<ffffffff811b38a6>] ? link_path_walk+0x286/0x8a0\r\nMay 24 16:09:53 haggis kernel: [23405.713633]  [<ffffffff811b7adb>] ? path_openat+0xbb/0x680\r\nMay 24 16:09:53 haggis kernel: [23405.713640]  [<ffffffff8117abb5>] ? free_pages_and_swap_cache+0x95/0xb0\r\nMay 24 16:09:53 haggis kernel: [23405.713646]  [<ffffffff811b884a>] ? do_filp_open+0x3a/0x90\r\nMay 24 16:09:53 haggis kernel: [23405.713653]  [<ffffffff811c48ac>] ? __alloc_fd+0x7c/0x120\r\nMay 24 16:09:53 haggis kernel: [23405.713660]  [<ffffffff811a7ae9>] ? do_sys_open+0x129/0x220\r\nMay 24 16:09:53 haggis kernel: [23405.713669]  [<ffffffff81514a0d>] ? system_call_fast_compare_end+0x10/0x15\r\nMay 24 16:09:53 haggis kernel: [23405.714001] qemu-system-x86 D ffff88044ef746e8     0 15748      1 0x00000000\r\nMay 24 16:09:53 haggis kernel: [23405.714008]  ffff88044ef74290 0000000000000082 0000000000012f00 ffff8803d055bfd8\r\nMay 24 16:09:53 haggis kernel: [23405.714013]  0000000000012f00 ffff88044ef74290 ffffffffa0e00ce0 ffff8803d055be58\r\nMay 24 16:09:53 haggis kernel: [23405.714018]  ffffffffa0e00ce4 ffff88044ef74290 00000000ffffffff ffffffffa0e00ce8\r\nMay 24 16:09:53 haggis kernel: [23405.714024] Call Trace:\r\nMay 24 16:09:53 haggis kernel: [23405.714037]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:09:53 haggis kernel: [23405.714043]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:09:53 haggis kernel: [23405.714052]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:09:53 haggis kernel: [23405.714095]  [<ffffffffa0c55d36>] ? zvol_release+0x36/0x90 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714102]  [<ffffffff811dd32d>] ? __blkdev_put+0x15d/0x1a0\r\nMay 24 16:09:53 haggis kernel: [23405.714109]  [<ffffffff811ddd81>] ? blkdev_close+0x21/0x30\r\nMay 24 16:09:53 haggis kernel: [23405.714114]  [<ffffffff811aa1ea>] ? __fput+0xca/0x1d0\r\nMay 24 16:09:53 haggis kernel: [23405.714121]  [<ffffffff810852dc>] ? task_work_run+0x8c/0xb0\r\nMay 24 16:09:53 haggis kernel: [23405.714129]  [<ffffffff81012e99>] ? do_notify_resume+0x69/0xa0\r\nMay 24 16:09:53 haggis kernel: [23405.714136]  [<ffffffff81514cca>] ? int_signal+0x12/0x17\r\nMay 24 16:09:53 haggis kernel: [23405.714152] zpool           D ffff8802865d70b8     0 15932  15869 0x00000004\r\nMay 24 16:09:53 haggis kernel: [23405.714157]  ffff8802865d6c60 0000000000000082 0000000000012f00 ffff88037bcbbfd8\r\nMay 24 16:09:53 haggis kernel: [23405.714163]  0000000000012f00 ffff8802865d6c60 ffff8803e4930a98 ffff88037bcbbb28\r\nMay 24 16:09:53 haggis kernel: [23405.714168]  ffff8803e4930a9c ffff8802865d6c60 00000000ffffffff ffff8803e4930aa0\r\nMay 24 16:09:53 haggis kernel: [23405.714173] Call Trace:\r\nMay 24 16:09:53 haggis kernel: [23405.714179]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:09:53 haggis kernel: [23405.714184]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:09:53 haggis kernel: [23405.714192]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:09:53 haggis kernel: [23405.714198]  [<ffffffff811dd3d3>] ? __blkdev_get+0x63/0x480\r\nMay 24 16:09:53 haggis kernel: [23405.714204]  [<ffffffff811dd9fb>] ? blkdev_get+0x20b/0x310\r\nMay 24 16:09:53 haggis kernel: [23405.714212]  [<ffffffff811be3df>] ? dput+0x1f/0x170\r\nMay 24 16:09:53 haggis kernel: [23405.714218]  [<ffffffff811ddd24>] ? blkdev_get_by_path+0x54/0x90\r\nMay 24 16:09:53 haggis kernel: [23405.714265]  [<ffffffffa0c0aad5>] ? vdev_disk_open+0x355/0x3c0 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714309]  [<ffffffffa0c07cd8>] ? vdev_open+0xe8/0x500 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714350]  [<ffffffffa0c55dad>] ? zvol_is_zvol+0x1d/0x40 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714389]  [<ffffffffa0c08144>] ? vdev_open_children+0x54/0x170 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714430]  [<ffffffffa0c11853>] ? vdev_root_open+0x43/0xe0 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714466]  [<ffffffffa0c07cd8>] ? vdev_open+0xe8/0x500 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714501]  [<ffffffffa0c082cd>] ? vdev_create+0x1d/0xa0 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714512]  [<ffffffffa0a0313e>] ? zfs_allocatable_devs+0x5e/0x80 [zcommon]\r\nMay 24 16:09:53 haggis kernel: [23405.714559]  [<ffffffffa0bf5f3f>] ? spa_create+0x36f/0x9a0 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714601]  [<ffffffffa0c27309>] ? zfs_fill_zplprops_impl+0x1d9/0x380 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714641]  [<ffffffffa0c2b3a4>] ? zfs_ioc_pool_create+0x144/0x260 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714679]  [<ffffffffa0c29669>] ? zfsdev_ioctl+0x4a9/0x4e0 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714686]  [<ffffffff811bacdf>] ? do_vfs_ioctl+0x2cf/0x4b0\r\nMay 24 16:09:53 haggis kernel: [23405.714692]  [<ffffffff811baf41>] ? SyS_ioctl+0x81/0xa0\r\nMay 24 16:09:53 haggis kernel: [23405.714698]  [<ffffffff81516a28>] ? page_fault+0x28/0x30\r\nMay 24 16:09:53 haggis kernel: [23405.714705]  [<ffffffff81514a0d>] ? system_call_fast_compare_end+0x10/0x15\r\nMay 24 16:09:53 haggis kernel: [23405.714775] zpool           D ffff8803a5306568     0 16377  15894 0x00000000\r\nMay 24 16:09:53 haggis kernel: [23405.714781]  ffff8803a5306110 0000000000000082 0000000000012f00 ffff88037de3ffd8\r\nMay 24 16:09:53 haggis kernel: [23405.714786]  0000000000012f00 ffff8803a5306110 ffffffffa0d7cb20 ffff88037de3fe28\r\nMay 24 16:09:53 haggis kernel: [23405.714791]  ffffffffa0d7cb24 ffff8803a5306110 00000000ffffffff ffffffffa0d7cb28\r\nMay 24 16:09:53 haggis kernel: [23405.714797] Call Trace:\r\nMay 24 16:09:53 haggis kernel: [23405.714807]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:09:53 haggis kernel: [23405.714813]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:09:53 haggis kernel: [23405.714821]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:09:53 haggis kernel: [23405.714868]  [<ffffffffa0bf94f9>] ? spa_all_configs+0x49/0x180 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714905]  [<ffffffffa0c26906>] ? zfs_ioc_pool_configs+0x16/0x40 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714942]  [<ffffffffa0c29669>] ? zfsdev_ioctl+0x4a9/0x4e0 [zfs]\r\nMay 24 16:09:53 haggis kernel: [23405.714949]  [<ffffffff811bacdf>] ? do_vfs_ioctl+0x2cf/0x4b0\r\nMay 24 16:09:53 haggis kernel: [23405.714955]  [<ffffffff811baf41>] ? SyS_ioctl+0x81/0xa0\r\nMay 24 16:09:53 haggis kernel: [23405.714960]  [<ffffffff81516a28>] ? page_fault+0x28/0x30\r\nMay 24 16:09:53 haggis kernel: [23405.714967]  [<ffffffff81514a0d>] ? system_call_fast_compare_end+0x10/0x15\r\nMay 24 16:11:53 haggis kernel: [23525.741944] systemd-udevd   D ffff880468c9d908     0   371      1 0x00000000\r\nMay 24 16:11:53 haggis kernel: [23525.741953]  ffff880468c9d4b0 0000000000000086 0000000000012f00 ffff88046c06bfd8\r\nMay 24 16:11:53 haggis kernel: [23525.741959]  0000000000012f00 ffff880468c9d4b0 ffffffffa0d7cb20 ffff88046c06ba90\r\nMay 24 16:11:53 haggis kernel: [23525.741965]  ffffffffa0d7cb24 ffff880468c9d4b0 00000000ffffffff ffffffffa0d7cb28\r\nMay 24 16:11:53 haggis kernel: [23525.741971] Call Trace:\r\nMay 24 16:11:53 haggis kernel: [23525.742001]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:11:53 haggis kernel: [23525.742008]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:11:53 haggis kernel: [23525.742018]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:11:53 haggis kernel: [23525.742086]  [<ffffffffa0bf4e6e>] ? spa_open_common+0x4e/0x460 [zfs]\r\nMay 24 16:11:53 haggis kernel: [23525.742102]  [<ffffffffa0b622ef>] ? tsd_hash_dtor+0x6f/0x80 [spl]\r\nMay 24 16:11:53 haggis kernel: [23525.742153]  [<ffffffffa0bd860e>] ? dsl_pool_hold+0x1e/0x50 [zfs]\r\nMay 24 16:11:53 haggis kernel: [23525.742190]  [<ffffffffa0bb5842>] ? dmu_objset_hold+0x22/0xb0 [zfs]\r\nMay 24 16:11:53 haggis kernel: [23525.742234]  [<ffffffffa0bd8d9e>] ? dsl_prop_get+0x2e/0x80 [zfs]\r\nMay 24 16:11:53 haggis kernel: [23525.742277]  [<ffffffffa0c54a8a>] ? zvol_open+0x15a/0x290 [zfs]\r\nMay 24 16:11:53 haggis kernel: [23525.742293]  [<ffffffff811dd43c>] ? __blkdev_get+0xcc/0x480\r\nMay 24 16:11:53 haggis kernel: [23525.742300]  [<ffffffff811ddb40>] ? blkdev_get_by_dev+0x40/0x40\r\nMay 24 16:11:53 haggis kernel: [23525.742306]  [<ffffffff811dd9a6>] ? blkdev_get+0x1b6/0x310\r\nMay 24 16:11:53 haggis kernel: [23525.742313]  [<ffffffff811ddb40>] ? blkdev_get_by_dev+0x40/0x40\r\nMay 24 16:11:53 haggis kernel: [23525.742323]  [<ffffffff811a62a2>] ? do_dentry_open+0x1f2/0x330\r\nMay 24 16:11:53 haggis kernel: [23525.742330]  [<ffffffff811a65ad>] ? finish_open+0x2d/0x40\r\nMay 24 16:11:53 haggis kernel: [23525.742337]  [<ffffffff811b72ca>] ? do_last+0xaaa/0x1200\r\nMay 24 16:11:53 haggis kernel: [23525.742342]  [<ffffffff811b38a6>] ? link_path_walk+0x286/0x8a0\r\nMay 24 16:11:53 haggis kernel: [23525.742348]  [<ffffffff811b7adb>] ? path_openat+0xbb/0x680\r\nMay 24 16:11:53 haggis kernel: [23525.742356]  [<ffffffff8117abb5>] ? free_pages_and_swap_cache+0x95/0xb0\r\nMay 24 16:11:53 haggis kernel: [23525.742362]  [<ffffffff811b884a>] ? do_filp_open+0x3a/0x90\r\nMay 24 16:11:53 haggis kernel: [23525.742369]  [<ffffffff811c48ac>] ? __alloc_fd+0x7c/0x120\r\nMay 24 16:11:53 haggis kernel: [23525.742377]  [<ffffffff811a7ae9>] ? do_sys_open+0x129/0x220\r\nMay 24 16:11:53 haggis kernel: [23525.742385]  [<ffffffff81514a0d>] ? system_call_fast_compare_end+0x10/0x15\r\nMay 24 16:11:53 haggis kernel: [23525.742712] qemu-system-x86 D ffff88044ef746e8     0 15748      1 0x00000000\r\nMay 24 16:11:53 haggis kernel: [23525.742719]  ffff88044ef74290 0000000000000082 0000000000012f00 ffff8803d055bfd8\r\nMay 24 16:11:53 haggis kernel: [23525.742725]  0000000000012f00 ffff88044ef74290 ffffffffa0e00ce0 ffff8803d055be58\r\nMay 24 16:11:53 haggis kernel: [23525.742730]  ffffffffa0e00ce4 ffff88044ef74290 00000000ffffffff ffffffffa0e00ce8\r\nMay 24 16:11:53 haggis kernel: [23525.742735] Call Trace:\r\nMay 24 16:11:53 haggis kernel: [23525.742747]  [<ffffffff815115f5>] ? schedule_preempt_disabled+0x25/0x70\r\nMay 24 16:11:53 haggis kernel: [23525.742753]  [<ffffffff815130a3>] ? __mutex_lock_slowpath+0xd3/0x1c0\r\nMay 24 16:11:53 haggis kernel: [23525.742762]  [<ffffffff815131ab>] ? mutex_lock+0x1b/0x2a\r\nMay 24 16:11:53 haggis kernel: [23525.742803]  [<ffffffffa0c55d36>] ? zvol_release+0x36/0x90 [zfs]\r\nMay 24 16:11:53 haggis kernel: [23525.742811]  [<ffffffff811dd32d>] ? __blkdev_put+0x15d/0x1a0\r\nMay 24 16:11:53 haggis kernel: [23525.742817]  [<ffffffff811ddd81>] ? blkdev_close+0x21/0x30\r\nMay 24 16:11:53 haggis kernel: [23525.742823]  [<ffffffff811aa1ea>] ? __fput+0xca/0x1d0\r\nMay 24 16:11:53 haggis kernel: [23525.742830]  [<ffffffff810852dc>] ? task_work_run+0x8c/0xb0\r\nMay 24 16:11:53 haggis kernel: [23525.742839]  [<ffffffff81012e99>] ? do_notify_resume+0x69/0xa0\r\nMay 24 16:11:53 haggis kernel: [23525.742846]  [<ffffffff81514cca>] ? int_signal+0x12/0x17\r\n```\r\n\r\nNote that this case is different from #2469"},"comment":{"url":"https://api.github.com/repos/zfsonlinux/zfs/issues/comments/221422313","html_url":"https://github.com/zfsonlinux/zfs/issues/4694#issuecomment-221422313","issue_url":"https://api.github.com/repos/zfsonlinux/zfs/issues/4694","id":221422313,"user":{"login":"behlendorf","id":148917,"avatar_url":"https://avatars.githubusercontent.com/u/148917?v=3","gravatar_id":"","url":"https://api.github.com/users/behlendorf","html_url":"https://github.com/behlendorf","followers_url":"https://api.github.com/users/behlendorf/followers","following_url":"https://api.github.com/users/behlendorf/following{/other_user}","gists_url":"https://api.github.com/users/behlendorf/gists{/gist_id}","starred_url":"https://api.github.com/users/behlendorf/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/behlendorf/subscriptions","organizations_url":"https://api.github.com/users/behlendorf/orgs","repos_url":"https://api.github.com/users/behlendorf/repos","events_url":"https://api.github.com/users/behlendorf/events{/privacy}","received_events_url":"https://api.github.com/users/behlendorf/received_events","type":"User","site_admin":false},"created_at":"2016-05-24T22:34:25Z","updated_at":"2016-05-24T22:34:25Z","body":"@nigoroll actually on Solaris-ish systems this isn't 100% safe either and may deadlock.  It just happens to be much much more likely with ZoL due to a greater degree of concurrency allowed in the Linux block layer.  But your definitely right this can deadlock and should be resolved, patches welcome.  :)"}}
{"actor":{"display_login":"behlendorf"}}