syzbot

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BUG: KMSAN: uninit-value in ttwu_do_activate kernel/sched/core.c:1693 [inline]
BUG: KMSAN: uninit-value in ttwu_queue kernel/sched/core.c:1845 [inline]
BUG: KMSAN: uninit-value in try_to_wake_up+0x1c66/0x20b0 kernel/sched/core.c:2058
CPU: 1 PID: 4804 Comm: kworker/1:2 Not tainted 4.17.0-rc5+ #103
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rcu_gp srcu_invoke_callbacks
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x149/0x260 mm/kmsan/kmsan.c:1084
 __msan_warning_32+0x6e/0xc0 mm/kmsan/kmsan_instr.c:686
 ttwu_do_activate kernel/sched/core.c:1693 [inline]
 ttwu_queue kernel/sched/core.c:1845 [inline]
 try_to_wake_up+0x1c66/0x20b0 kernel/sched/core.c:2058
 default_wake_function+0x92/0xb0 kernel/sched/core.c:3745
 __wake_up_common kernel/sched/wait.c:90 [inline]
 __wake_up_locked+0x216/0x370 kernel/sched/wait.c:152
 complete+0xe8/0x180 kernel/sched/completion.c:36
 wakeme_after_rcu+0x19/0x20 kernel/rcu/update.c:377
 srcu_invoke_callbacks+0x2ae/0x640 kernel/rcu/srcutree.c:1187
 process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2145
 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2279
 kthread+0x4e3/0x6d0 kernel/kthread.c:241
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:412

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:294 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:685
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:529
 try_to_wake_up+0xcaa/0x20b0 kernel/sched/core.c:2035
 default_wake_function+0x92/0xb0 kernel/sched/core.c:3745
 __wake_up_common kernel/sched/wait.c:90 [inline]
 __wake_up_locked+0x216/0x370 kernel/sched/wait.c:152
 complete+0xe8/0x180 kernel/sched/completion.c:36
 wakeme_after_rcu+0x19/0x20 kernel/rcu/update.c:377
 srcu_invoke_callbacks+0x2ae/0x640 kernel/rcu/srcutree.c:1187
 process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2145
 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2279
 kthread+0x4e3/0x6d0 kernel/kthread.c:241
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:412
Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:294 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:685
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:529
 do_wait_for_common kernel/sched/completion.c:81 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common+0x4fb/0x940 kernel/sched/completion.c:115
 wait_for_completion+0x3e/0x50 kernel/sched/completion.c:136
 __synchronize_srcu+0x2ac/0x320 kernel/rcu/srcutree.c:924
 synchronize_srcu+0x347/0x420 kernel/rcu/srcutree.c:1002
 blk_mq_quiesce_queue+0x1b2/0x250 block/blk-mq.c:236
 nbd_clear_que drivers/block/nbd.c:661 [inline]
 nbd_clear_sock drivers/block/nbd.c:1015 [inline]
 nbd_config_put+0x320/0x8e0 drivers/block/nbd.c:1030
 nbd_release+0x54/0x80 drivers/block/nbd.c:1281
 __blkdev_put+0x8e7/0xc80 fs/block_dev.c:1790
 blkdev_put+0x435/0x570 fs/block_dev.c:1852
 blkdev_close+0xa6/0xf0 fs/block_dev.c:1859
 __fput+0x457/0xa10 fs/file_table.c:209
 ____fput+0x37/0x40 fs/file_table.c:243
 task_work_run+0x243/0x2c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x10e1/0x38d0 kernel/exit.c:867
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0xfcb/0x1f40 kernel/signal.c:2482
 do_signal+0xb8/0x1cf0 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:162 [inline]
 prepare_exit_to_usermode+0x271/0x3a0 arch/x86/entry/common.c:196
 syscall_return_slowpath+0xe9/0x700 arch/x86/entry/common.c:265
 do_syscall_64+0x1af/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Local variable description: ----flags.i.i.i.i@_raw_spin_lock_irqsave
Variable was created at:
 _raw_spin_lock_irqsave+0x45/0xf0 kernel/locking/spinlock.c:150
 hrtimer_interrupt+0x107/0x13c0 kernel/time/hrtimer.c:1499
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