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BUG: KMSAN: uninit-value in lock_timer_base kernel/time/timer.c:939 [inline]
BUG: KMSAN: uninit-value in __mod_timer+0x42d/0x2bf0 kernel/time/timer.c:1010
CPU: 1 PID: 29694 Comm: loop0 Not tainted 4.17.0+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1125
 __msan_warning_32+0x70/0xc0 mm/kmsan/kmsan_instr.c:620
 lock_timer_base kernel/time/timer.c:939 [inline]
 __mod_timer+0x42d/0x2bf0 kernel/time/timer.c:1010
 mod_timer+0x70/0x80 kernel/time/timer.c:1102
 wb_domain_writeout_inc mm/page-writeback.c:592 [inline]
 __wb_writeout_inc+0x456/0x4b0 mm/page-writeback.c:605
 test_clear_page_writeback+0x9c9/0x10c0 mm/page-writeback.c:2731
 end_page_writeback+0x1a2/0x2d0 mm/filemap.c:1229
 end_buffer_async_write+0x675/0xbe0 fs/buffer.c:347
 end_bio_bh_io_sync+0x125/0x1c0 fs/buffer.c:2974
 bio_endio+0xaa3/0xc80 block/bio.c:1784
 req_bio_endio block/blk-core.c:284 [inline]
 blk_update_request+0xea8/0x1ae0 block/blk-core.c:3100
 blk_mq_end_request+0x9b/0x2d0 block/blk-mq.c:523
 lo_complete_rq+0x1fa/0x3c0 drivers/block/loop.c:482
 __blk_mq_complete_request+0x73f/0x9b0 block/blk-mq.c:567
 blk_mq_complete_request+0x36f/0x440 block/blk-mq.c:652
 loop_handle_cmd drivers/block/loop.c:1778 [inline]
 loop_queue_work+0x3c7a/0x3e30 drivers/block/loop.c:1787
 kthread_worker_fn+0x595/0x900 kernel/kthread.c:638
 loop_kthread_worker_fn+0x90/0xb0 drivers/block/loop.c:863
 kthread+0x4db/0x6c0 kernel/kthread.c:241
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:413

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:282 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:297 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:689
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:464
 timer_set_idx kernel/time/timer.c:480 [inline]
 enqueue_timer kernel/time/timer.c:539 [inline]
 __internal_add_timer kernel/time/timer.c:548 [inline]
 internal_add_timer kernel/time/timer.c:590 [inline]
 __mod_timer+0x22a1/0x2bf0 kernel/time/timer.c:1055
 mod_timer+0x70/0x80 kernel/time/timer.c:1102
 writeout_period+0x1df/0x290 mm/page-writeback.c:637
 call_timer_fn+0x280/0x5d0 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers+0xd96/0x11b0 kernel/time/timer.c:1666
 run_timer_softirq+0x5f/0x70 kernel/time/timer.c:1694
 __do_softirq+0x592/0x979 kernel/softirq.c:285

Local variable description: ----heads@__run_timers
Variable was created at:
 __run_timers+0x84/0x11b0 kernel/time/timer.c:1651
 run_timer_softirq+0x43/0x70 kernel/time/timer.c:1692
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