{"action":"opened","issue":{"url":"https://api.github.com/repos/zfsonlinux/zfs/issues/5413","repository_url":"https://api.github.com/repos/zfsonlinux/zfs","labels_url":"https://api.github.com/repos/zfsonlinux/zfs/issues/5413/labels{/name}","comments_url":"https://api.github.com/repos/zfsonlinux/zfs/issues/5413/comments","events_url":"https://api.github.com/repos/zfsonlinux/zfs/issues/5413/events","html_url":"https://github.com/zfsonlinux/zfs/issues/5413","id":190441639,"number":5413,"title":"zfs_setattr(): possible recursive locking","user":{"login":"ironMann","id":276684,"avatar_url":"https://avatars.githubusercontent.com/u/276684?v=3","gravatar_id":"","url":"https://api.github.com/users/ironMann","html_url":"https://github.com/ironMann","followers_url":"https://api.github.com/users/ironMann/followers","following_url":"https://api.github.com/users/ironMann/following{/other_user}","gists_url":"https://api.github.com/users/ironMann/gists{/gist_id}","starred_url":"https://api.github.com/users/ironMann/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ironMann/subscriptions","organizations_url":"https://api.github.com/users/ironMann/orgs","repos_url":"https://api.github.com/users/ironMann/repos","events_url":"https://api.github.com/users/ironMann/events{/privacy}","received_events_url":"https://api.github.com/users/ironMann/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":0,"created_at":"2016-11-18T22:55:12Z","updated_at":"2016-11-18T22:55:12Z","closed_at":null,"body":"I see this occasionally on the master branch. Triggered by unpacking kernel archive in freshly created FS. No special parameters.\r\n\r\n```\r\n[  244.009075] =============================================\r\n[  244.009384] [ INFO: possible recursive locking detected ]\r\n[  244.009677] 4.8.6-201.fc24.x86_64+debug #1 Tainted: G           OE\r\n[  244.010004] ---------------------------------------------\r\n[  244.010285] tar/6995 is trying to acquire lock:\r\n[  244.010551]  (&zp->z_acl_lock){+.+...}, at: [<ffffffffc0a778a6>] zfs_setattr+0x6e6/0x2510 [zfs]\r\n[  244.011564] but task is already holding lock:\r\n[  244.011938]  (&zp->z_acl_lock){+.+...}, at: [<ffffffffc0a777b9>] zfs_setattr+0x5f9/0x2510 [zfs]\r\n[  244.012919] other info that might help us debug this:\r\n[  244.013611]  Possible unsafe locking scenario:\r\n[  244.014624]        CPU0\r\n[  244.015264]        ----\r\n[  244.015904]   lock(&zp->z_acl_lock);\r\n[  244.016806]   lock(&zp->z_acl_lock);\r\n[  244.017670]\r\n                *** DEADLOCK ***\r\n[  244.019038]  May be due to missing lock nesting notation\r\n\r\n[  244.020051] 4 locks held by tar/6995:\r\n[  244.020646]  #0:  (sb_writers#17){.+.+.+}, at: [<ffffffffa02a51c4>] __sb_start_write+0xb4/0xf0\r\n[  244.023483]  #1:  (&sb->s_type->i_mutex_key#20){+.+.+.}, at: [<ffffffffa029e96d>] chown_common.isra.10+0x12d/0x1d0\r\n[  244.025892]  #2:  (&zp->z_acl_lock){+.+...}, at: [<ffffffffc0a777b9>] zfs_setattr+0x5f9/0x2510 [zfs]\r\n[  244.027932]  #3:  (&zp->z_lock){+.+...}, at: [<ffffffffc0a7780c>] zfs_setattr+0x64c/0x2510 [zfs]\r\n[  244.038558] Call Trace:\r\n[  244.039133]  [<ffffffffa0466043>] ? dump_stack+0x86/0xc3\r\n[  244.039805]  [<ffffffffa0466043>] dump_stack+0x86/0xc3\r\n[  244.040451]  [<ffffffffa010efee>] __lock_acquire+0x78e/0x1290\r\n[  244.041773]  [<ffffffffa010ff56>] lock_acquire+0xf6/0x1f0\r\n[  244.042467]  [<ffffffffc0a778a6>] ? zfs_setattr+0x6e6/0x2510 [zfs]\r\n[  244.043156]  [<ffffffffa08f2896>] mutex_lock_nested+0x86/0x3f0\r\n[  244.043884]  [<ffffffffc0a778a6>] ? zfs_setattr+0x6e6/0x2510 [zfs]\r\n[  244.044583]  [<ffffffffc0a778a6>] ? zfs_setattr+0x6e6/0x2510 [zfs]\r\n[  244.045294]  [<ffffffffa08f2815>] ? mutex_lock_nested+0x5/0x3f0\r\n[  244.046010]  [<ffffffffc0a778a6>] zfs_setattr+0x6e6/0x2510 [zfs]\r\n[  244.046693]  [<ffffffffc07e62c1>] ? spl_kmem_zalloc+0xc1/0x1a0 [spl]\r\n[  244.047411]  [<ffffffffc0a771c5>] ? zfs_setattr+0x5/0x2510 [zfs]\r\n[  244.048099]  [<ffffffffc0aa87b5>] zpl_setattr+0x115/0x230 [zfs]\r\n[  244.049256]  [<ffffffffa02c4b83>] notify_change+0x313/0x450\r\n[  244.049945]  [<ffffffffa029e987>] chown_common.isra.10+0x147/0x1d0\r\n[  244.050618]  [<ffffffffa02a001f>] SyS_fchown+0x8f/0xa0\r\n[  244.051243]  [<ffffffffa08f6b3c>] entry_SYSCALL_64_fastpath+0x1f/0xbd\r\n```"}}
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