zfs send throwing "SPL: Showing stack for process 1081" errors into syslog every few seconds

[darkpixel]

Sep 14 18:00:23 spark kernel: [ 1742.947981] SPL: Showing stack for process 1081
Sep 14 18:00:23 spark kernel: [ 1742.947988] Pid: 1081, comm: txg_sync Tainted: PF          O 3.8.0-30-generic #44-Ubuntu
Sep 14 18:00:23 spark kernel: [ 1742.947990] Call Trace:
Sep 14 18:00:23 spark kernel: [ 1742.948031]  [<ffffffffa0271557>] spl_debug_dumpstack+0x27/0x40 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948044]  [<ffffffffa02842c3>] sanitize_flags.part.10+0x68/0xda5 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948057]  [<ffffffffa0276cb7>] kmem_alloc_debug+0x387/0x3b0 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948063]  [<ffffffff81351522>] ? number.isra.2+0x322/0x360
Sep 14 18:00:23 spark kernel: [ 1742.948076]  [<ffffffffa027b28f>] task_alloc+0x18f/0x340 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948086]  [<ffffffffa02769c6>] ? kmem_alloc_debug+0x96/0x3b0 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948141]  [<ffffffffa0356b30>] ? spa_add+0x4f0/0x4f0 [zfs]
Sep 14 18:00:23 spark kernel: [ 1742.948153]  [<ffffffffa027b5db>] taskq_dispatch_delay+0x19b/0x2b0 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948163]  [<ffffffffa027b002>] ? taskq_cancel_id+0xf2/0x1f0 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948169]  [<ffffffff810ac178>] ? ktime_get_ts+0x48/0xe0
Sep 14 18:00:23 spark kernel: [ 1742.948206]  [<ffffffffa034b0ee>] spa_sync+0x20e/0xaf0 [zfs]
Sep 14 18:00:23 spark kernel: [ 1742.948211]  [<ffffffff8101b579>] ? read_tsc+0x9/0x20
Sep 14 18:00:23 spark kernel: [ 1742.948214]  [<ffffffff810ac178>] ? ktime_get_ts+0x48/0xe0
Sep 14 18:00:23 spark kernel: [ 1742.948253]  [<ffffffffa035aef3>] txg_sync_thread+0x323/0x590 [zfs]
Sep 14 18:00:23 spark kernel: [ 1742.948292]  [<ffffffffa035abd0>] ? txg_init+0x250/0x250 [zfs]
Sep 14 18:00:23 spark kernel: [ 1742.948304]  [<ffffffffa0279ba8>] thread_generic_wrapper+0x78/0x90 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948314]  [<ffffffffa0279b30>] ? __thread_create+0x340/0x340 [spl]
Sep 14 18:00:23 spark kernel: [ 1742.948318]  [<ffffffff8107d590>] kthread+0xc0/0xd0
Sep 14 18:00:23 spark kernel: [ 1742.948322]  [<ffffffff8107d4d0>] ? kthread_create_on_node+0x120/0x120
Sep 14 18:00:23 spark kernel: [ 1742.948326]  [<ffffffff816d56ac>] ret_from_fork+0x7c/0xb0
Sep 14 18:00:23 spark kernel: [ 1742.948330]  [<ffffffff8107d4d0>] ? kthread_create_on_node+0x120/0x120

[dweeezil]

@darkpixel More fallout from the restructured sync task. Give the patch at dweeezil/zfs@81adb07 a try.

[dweeezil]

I forgot to mention that this should probably be a zfs issue rather than an spl issue.

[behlendorf]

Closing. This issue was resolved.