Stephen R. van den Berg wrote: >Stephen R. van den Berg wrote: >>Qu Wenruo wrote: >>>>> It's caused by qgroup, and a dead lock on btrfs_drop_snapshot(). >>>>> Please either disable qgroup or apply this patch to solve it: >>>>> https://patchwork.kernel.org/patch/10725371/ >>Ok, booting the system in v4.20 with this patch. I'll report back if >>it does not resolve the problem. Ok, I now have a sysreq+w output again (attached at the bottom). In userspace I see the following (ps xfa): 1282 ? D 5:57 \_ [btrfs-cleaner] 1283 ? D 26:09 \_ [btrfs-transacti] 18526 ? D 0:09 | \_ btrfs receive --max-errors 1 -vv /data/lxc/somecontainer/rootfs The btrfs receive hangs and does not proceed. The dmesg output prior to running the sysreq+w: [11651.269729] perf: interrupt took too long (3154 > 3136), lowering kernel.perf_event_max_sample_rate to 63400 [14867.617253] INFO: task btrfs:24867 blocked for more than 120 seconds. [14867.622513] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [14867.628202] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [14867.634845] btrfs D 0 24867 24862 0x00000000 [14867.639173] Call Trace: [14867.640436] ? __schedule+0x4db/0x524 [14867.642904] ? schedule+0x60/0x71 [14867.645029] ? btrfs_start_ordered_extent+0xd3/0x105 [14867.648818] ? finish_wait+0x60/0x60 [14867.651198] ? btrfs_wait_ordered_range+0xa4/0x100 [14867.654795] ? unmap_mapping_pages+0x64/0x113 [14867.657979] ? btrfs_setattr+0x20b/0x499 [14867.660707] ? notify_change+0x268/0x347 [14867.663435] ? do_truncate+0x82/0xb6 [14867.665810] ? kmem_cache_alloc+0x9a/0x100 [14867.668726] ? vfs_truncate+0xbc/0xda [14867.671194] ? do_sys_truncate+0x60/0xa9 [14867.673926] ? do_syscall_64+0x4e/0x5b [14867.676479] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 [20498.479174] perf: interrupt took too long (3952 > 3942), lowering kernel.perf_event_max_sample_rate to 50600 [53253.444439] perf: interrupt took too long (4953 > 4940), lowering kernel.perf_event_max_sample_rate to 40300 [64758.167022] INFO: task btrfs:21633 blocked for more than 120 seconds. [64758.172267] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [64758.177906] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [64758.184541] btrfs D 0 21633 21626 0x00000000 [64758.188854] Call Trace: [64758.190114] ? __schedule+0x4db/0x524 [64758.192582] ? schedule+0x60/0x71 [64758.194698] ? btrfs_commit_transaction+0x21c/0x711 [64758.198401] ? finish_wait+0x60/0x60 [64758.200791] ? _btrfs_ioctl_set_received_subvol+0x27e/0x2ab [64758.205167] ? btrfs_ioctl+0x1572/0x2a51 [64758.207902] ? current_time+0x67/0x88 [64758.210369] ? pipe_write+0x356/0x369 [64758.212830] ? vfs_ioctl+0x1e/0x2b [64758.215030] ? btrfs_ioctl_get_supported_features+0x22/0x22 [64758.219422] ? vfs_ioctl+0x1e/0x2b [64758.221626] ? do_vfs_ioctl+0x523/0x54c [64758.224261] ? ksys_ioctl+0x3e/0x5d [64758.226548] ? __x64_sys_ioctl+0x16/0x19 [64758.229281] ? do_syscall_64+0x4e/0x5b [64758.231837] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 [87012.380856] conftest[12985]: segfault at 7ffe28de8aa0 ip 0000557f11bc31c4 sp 00007ffe28de8aa0 error 6 in conftest[557f11bc3000+1000] [87012.391632] Code: 1f 80 00 00 00 00 e9 7b ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 48 81 ec f8 ff 00 00 8b 05 8f 2e 00 00 48 8d 35 40 0e 00 00 <48> 89 3c 24 48 8b 3d 81 2e 00 00 8d 90 00 00 01 00 31 c0 89 15 6f [89521.271437] perf: interrupt took too long (6193 > 6191), lowering kernel.perf_event_max_sample_rate to 32200 [139102.477242] INFO: task btrfs-cleaner:1282 blocked for more than 120 seconds. [139102.483103] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139102.488730] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139102.495364] btrfs-cleaner D 0 1282 2 0x80000000 [139102.499687] Call Trace: [139102.500957] ? __schedule+0x4db/0x524 [139102.503418] ? __wait_for_common+0xda/0x160 [139102.506399] ? schedule+0x60/0x71 [139102.508536] ? wait_current_trans+0xa1/0xdf [139102.511522] ? finish_wait+0x60/0x60 [139102.513896] ? start_transaction+0x1b2/0x329 [139102.516964] ? btrfs_drop_snapshot+0x3d2/0x5de [139102.520239] ? btrfs_kill_all_delayed_nodes+0x5a/0xd1 [139102.524097] ? btrfs_delete_unused_bgs+0x39/0x39e [139102.527619] ? btrfs_need_cleaner_sleep+0x27/0x27 [139102.531127] ? btrfs_clean_one_deleted_snapshot+0xa8/0xb2 [139102.535329] ? cleaner_kthread+0x80/0xf6 [139102.538066] ? kthread+0xeb/0xf0 [139102.540097] ? kthread_associate_blkcg+0x86/0x86 [139102.543520] ? ret_from_fork+0x35/0x40 [139102.546070] INFO: task btrfs-transacti:1283 blocked for more than 120 seconds. [139102.552115] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139102.557713] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139102.564344] btrfs-transacti D 0 1283 2 0x80000000 [139102.568659] Call Trace: [139102.569917] ? __schedule+0x4db/0x524 [139102.572383] ? schedule+0x60/0x71 [139102.574495] ? btrfs_start_ordered_extent+0xd3/0x105 [139102.578283] ? finish_wait+0x60/0x60 [139102.580660] ? btrfs_wait_ordered_range+0xa4/0x100 [139102.584254] ? btrfs_get_token_32+0x8e/0xf4 [139102.587258] ? __btrfs_wait_cache_io+0x47/0x16d [139102.590594] ? btrfs_write_dirty_block_groups+0xc7/0x2d3 [139102.594707] ? btrfs_run_delayed_refs+0xdf/0x12d [139102.598149] ? commit_cowonly_roots+0x1f3/0x2a8 [139102.601493] ? btrfs_commit_transaction+0x397/0x711 [139102.605178] ? finish_wait+0x60/0x60 [139102.607568] ? transaction_kthread+0xc6/0x132 [139102.610732] ? btrfs_cleanup_transaction+0x3ca/0x3ca [139102.614495] ? kthread+0xeb/0xf0 [139102.616522] ? kthread_associate_blkcg+0x86/0x86 [139102.619961] ? ret_from_fork+0x35/0x40 [139471.126602] INFO: task btrfs-cleaner:1282 blocked for more than 120 seconds. [139471.132462] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139471.138099] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139471.144733] btrfs-cleaner D 0 1282 2 0x80000000 [139471.149046] Call Trace: [139471.150306] ? __schedule+0x4db/0x524 [139471.152775] ? __wait_for_common+0xda/0x160 [139471.155758] ? schedule+0x60/0x71 [139471.157896] ? wait_current_trans+0xa1/0xdf [139471.160885] ? finish_wait+0x60/0x60 [139471.163265] ? start_transaction+0x1b2/0x329 [139471.166334] ? btrfs_drop_snapshot+0x3d2/0x5de [139471.169609] ? btrfs_kill_all_delayed_nodes+0x5a/0xd1 [139471.173467] ? btrfs_delete_unused_bgs+0x39/0x39e [139471.176996] ? btrfs_need_cleaner_sleep+0x27/0x27 [139471.180504] ? btrfs_clean_one_deleted_snapshot+0xa8/0xb2 [139471.184707] ? cleaner_kthread+0x80/0xf6 [139471.187453] ? kthread+0xeb/0xf0 [139471.189483] ? kthread_associate_blkcg+0x86/0x86 [139471.192907] ? ret_from_fork+0x35/0x40 [139471.195456] INFO: task btrfs-transacti:1283 blocked for more than 120 seconds. [139471.201495] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139471.207088] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139471.213723] btrfs-transacti D 0 1283 2 0x80000000 [139471.218033] Call Trace: [139471.219282] ? __schedule+0x4db/0x524 [139471.221748] ? schedule+0x60/0x71 [139471.223862] ? btrfs_start_ordered_extent+0xd3/0x105 [139471.227660] ? finish_wait+0x60/0x60 [139471.230035] ? btrfs_wait_ordered_range+0xa4/0x100 [139471.233629] ? btrfs_get_token_32+0x8e/0xf4 [139471.236636] ? __btrfs_wait_cache_io+0x47/0x16d [139471.249343] ? btrfs_start_dirty_block_groups+0x111/0x390 [139471.253542] ? btrfs_commit_transaction+0xc9/0x711 [139471.257164] ? start_transaction+0x2b8/0x329 [139471.260241] ? transaction_kthread+0xc6/0x132 [139471.263402] ? btrfs_cleanup_transaction+0x3ca/0x3ca [139471.267184] ? kthread+0xeb/0xf0 [139471.269219] ? kthread_associate_blkcg+0x86/0x86 [139471.272640] ? ret_from_fork+0x35/0x40 [139594.009727] INFO: task btrfs-cleaner:1282 blocked for more than 120 seconds. [139594.015604] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139594.021226] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139594.027860] btrfs-cleaner D 0 1282 2 0x80000000 [139594.032188] Call Trace: [139594.033450] ? __schedule+0x4db/0x524 [139594.035913] ? __wait_for_common+0xda/0x160 [139594.038914] ? schedule+0x60/0x71 [139594.041057] ? wait_current_trans+0xa1/0xdf [139594.044046] ? finish_wait+0x60/0x60 [139594.046426] ? start_transaction+0x1b2/0x329 [139594.049503] ? btrfs_drop_snapshot+0x3d2/0x5de [139594.052772] ? btrfs_kill_all_delayed_nodes+0x5a/0xd1 [139594.056627] ? btrfs_delete_unused_bgs+0x39/0x39e [139594.060162] ? btrfs_need_cleaner_sleep+0x27/0x27 [139594.063672] ? btrfs_clean_one_deleted_snapshot+0xa8/0xb2 [139594.067875] ? cleaner_kthread+0x80/0xf6 [139594.070620] ? kthread+0xeb/0xf0 [139594.072650] ? kthread_associate_blkcg+0x86/0x86 [139594.076075] ? ret_from_fork+0x35/0x40 [139594.078622] INFO: task btrfs-transacti:1283 blocked for more than 120 seconds. [139594.084668] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139594.090271] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139594.096908] btrfs-transacti D 0 1283 2 0x80000000 [139594.101225] Call Trace: [139594.102481] ? __schedule+0x4db/0x524 [139594.104942] ? schedule+0x60/0x71 [139594.107059] ? btrfs_start_ordered_extent+0xd3/0x105 [139594.110853] ? finish_wait+0x60/0x60 [139594.113238] ? btrfs_wait_ordered_range+0xa4/0x100 [139594.116832] ? btrfs_get_token_32+0x8e/0xf4 [139594.119840] ? __btrfs_wait_cache_io+0x47/0x16d [139594.123181] ? btrfs_start_dirty_block_groups+0x111/0x390 [139594.127382] ? btrfs_commit_transaction+0xc9/0x711 [139594.131004] ? start_transaction+0x2b8/0x329 [139594.134083] ? transaction_kthread+0xc6/0x132 [139594.137244] ? btrfs_cleanup_transaction+0x3ca/0x3ca [139594.141032] ? kthread+0xeb/0xf0 [139594.143060] ? kthread_associate_blkcg+0x86/0x86 [139594.146475] ? ret_from_fork+0x35/0x40 [139716.892803] INFO: task btrfs-cleaner:1282 blocked for more than 120 seconds. [139716.898664] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139716.904287] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139716.910955] btrfs-cleaner D 0 1282 2 0x80000000 [139716.915275] Call Trace: [139716.916532] ? __schedule+0x4db/0x524 [139716.918993] ? __wait_for_common+0xda/0x160 [139716.921974] ? schedule+0x60/0x71 [139716.924126] ? wait_current_trans+0xa1/0xdf [139716.927115] ? finish_wait+0x60/0x60 [139716.929488] ? start_transaction+0x1b2/0x329 [139716.932558] ? btrfs_drop_snapshot+0x3d2/0x5de [139716.935834] ? btrfs_kill_all_delayed_nodes+0x5a/0xd1 [139716.939689] ? btrfs_delete_unused_bgs+0x39/0x39e [139716.943216] ? btrfs_need_cleaner_sleep+0x27/0x27 [139716.946729] ? btrfs_clean_one_deleted_snapshot+0xa8/0xb2 [139716.950931] ? cleaner_kthread+0x80/0xf6 [139716.953679] ? kthread+0xeb/0xf0 [139716.955706] ? kthread_associate_blkcg+0x86/0x86 [139716.959120] ? ret_from_fork+0x35/0x40 [139716.961672] INFO: task btrfs-transacti:1283 blocked for more than 120 seconds. [139716.967715] Not tainted 94.20.0-srb-asrock-00002-gfb1bd063cc72 #141 [139716.973313] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [139716.979946] btrfs-transacti D 0 1283 2 0x80000000 [139716.984257] Call Trace: [139716.985506] ? __schedule+0x4db/0x524 [139716.987975] ? schedule+0x60/0x71 [139716.990088] ? btrfs_start_ordered_extent+0xd3/0x105 [139716.993872] ? finish_wait+0x60/0x60 [139716.996251] ? btrfs_wait_ordered_range+0xa4/0x100 [139716.999848] ? btrfs_get_token_32+0x8e/0xf4 [139717.002853] ? __btrfs_wait_cache_io+0x47/0x16d [139717.006192] ? btrfs_start_dirty_block_groups+0x111/0x390 [139717.010397] ? btrfs_commit_transaction+0xc9/0x711 [139717.014016] ? start_transaction+0x2b8/0x329 [139717.017094] ? transaction_kthread+0xc6/0x132 [139717.020248] ? btrfs_cleanup_transaction+0x3ca/0x3ca [139717.024033] ? kthread+0xeb/0xf0 [139717.026065] ? kthread_associate_blkcg+0x86/0x86 [139717.029489] ? ret_from_fork+0x35/0x40 The latest sysreq+w output: sysrq: SysRq : Show Blocked State task PC stack pid father btrfs-cleaner D 0 1282 2 0x80000000 Call Trace: ? __schedule+0x4db/0x524 ? __wait_for_common+0xda/0x160 ? schedule+0x60/0x71 ? wait_current_trans+0xa1/0xdf ? finish_wait+0x60/0x60 ? start_transaction+0x1b2/0x329 ? btrfs_drop_snapshot+0x3d2/0x5de ? btrfs_kill_all_delayed_nodes+0x5a/0xd1 ? btrfs_delete_unused_bgs+0x39/0x39e ? btrfs_need_cleaner_sleep+0x27/0x27 ? btrfs_clean_one_deleted_snapshot+0xa8/0xb2 ? cleaner_kthread+0x80/0xf6 ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 btrfs-transacti D 0 1283 2 0x80000000 Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? btrfs_start_ordered_extent+0xd3/0x105 ? finish_wait+0x60/0x60 ? btrfs_wait_ordered_range+0xa4/0x100 ? btrfs_get_token_32+0x8e/0xf4 ? __btrfs_wait_cache_io+0x47/0x16d ? btrfs_start_dirty_block_groups+0x111/0x390 ? btrfs_commit_transaction+0xc9/0x711 ? start_transaction+0x2b8/0x329 ? transaction_kthread+0xc6/0x132 ? btrfs_cleanup_transaction+0x3ca/0x3ca ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 kworker/u16:1 D 0 19178 2 0x80000000 Workqueue: btrfs-endio-write btrfs_endio_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? usleep_range+0x7e/0x7e ? schedule+0x60/0x71 ? schedule_timeout+0x32/0xec ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 kworker/u16:3 D 0 3778 2 0x80000000 Workqueue: btrfs-endio-write btrfs_endio_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? usleep_range+0x7e/0x7e ? schedule+0x60/0x71 ? schedule_timeout+0x32/0xec ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 kworker/u16:14 D 0 4078 2 0x80000000 Workqueue: btrfs-endio-write btrfs_endio_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? usleep_range+0x7e/0x7e ? schedule+0x60/0x71 ? schedule_timeout+0x32/0xec ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 kworker/u16:17 D 0 4084 2 0x80000000 Workqueue: btrfs-freespace-write btrfs_freespace_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? sched_clock_cpu+0x10/0x9c ? try_to_wake_up+0x202/0x229 ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 btrfs D 0 18526 18521 0x00000000 Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? __set_extent_bit+0xff/0x3f8 ? __set_extent_bit+0x3c0/0x3f8 ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_buffered_write+0x4fd/0x5cf ? btrfs_file_write_iter+0x3a8/0x485 ? __vfs_write+0x9b/0xd9 ? vfs_write+0xa2/0xdf ? ksys_pwrite64+0x63/0x7f ? do_syscall_64+0x4e/0x5b ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 kworker/u16:12 D 0 24060 2 0x80000000 Workqueue: btrfs-endio-write btrfs_endio_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? usleep_range+0x7e/0x7e ? __slab_free.isra.72+0x89/0x1ba ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 kworker/u16:8 D 0 19152 2 0x80000000 Workqueue: btrfs-endio-write btrfs_endio_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? usleep_range+0x7e/0x7e ? schedule+0x60/0x71 ? schedule_timeout+0x32/0xec ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 kworker/u16:7 D 0 27825 2 0x80000000 Workqueue: btrfs-endio-write btrfs_endio_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? usleep_range+0x7e/0x7e ? schedule+0x60/0x71 ? schedule_timeout+0x32/0xec ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 kworker/u16:11 D 0 31266 2 0x80000000 Workqueue: btrfs-endio-write btrfs_endio_write_helper Call Trace: ? __schedule+0x4db/0x524 ? schedule+0x60/0x71 ? schedule_timeout+0xb2/0xec ? __next_timer_interrupt+0xae/0xae ? io_schedule_timeout+0x1b/0x3d ? balance_dirty_pages+0x7a7/0x861 ? usleep_range+0x7e/0x7e ? schedule+0x60/0x71 ? schedule_timeout+0x32/0xec ? balance_dirty_pages_ratelimited+0x204/0x225 ? btrfs_finish_ordered_io+0x584/0x5ac ? normal_work_helper+0xfe/0x243 ? process_one_work+0x18d/0x271 ? rescuer_thread+0x278/0x278 ? worker_thread+0x194/0x23f ? kthread+0xeb/0xf0 ? kthread_associate_blkcg+0x86/0x86 ? ret_from_fork+0x35/0x40 -- Stephen.
