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BUG: KCSAN: data-race in __xa_clear_mark / find_get_pages_range_tag

write to 0xffff88800a0476b0 of 8 bytes by interrupt on cpu 1:
 instrument_write include/linux/instrumented.h:42 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:79 [inline]
 __test_and_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:109 [inline]
 node_clear_mark lib/xarray.c:100 [inline]
 xas_clear_mark lib/xarray.c:911 [inline]
 __xa_clear_mark+0xff/0x1e0 lib/xarray.c:1916
 test_clear_page_writeback+0x321/0x520 mm/page-writeback.c:2739
 end_page_writeback+0xd7/0x260 mm/filemap.c:1498
 end_buffer_async_write+0x1b0/0x250 fs/buffer.c:375
 end_bio_bh_io_sync+0x6f/0x90 fs/buffer.c:3005
 bio_endio+0x28d/0x350 block/bio.c:1450
 req_bio_endio block/blk-core.c:264 [inline]
 blk_update_request+0x4f5/0xb40 block/blk-core.c:1462
 scsi_end_request+0x4d/0x460 drivers/scsi/scsi_lib.c:570
 scsi_io_completion+0x104/0x1000 drivers/scsi/scsi_lib.c:969
 scsi_finish_command+0x26e/0x2b0 drivers/scsi/scsi.c:214
 scsi_softirq_done+0xdf/0x440 drivers/scsi/scsi_lib.c:1449
 blk_done_softirq+0x145/0x190 block/blk-mq.c:588
 __do_softirq+0x13c/0x2c3 kernel/softirq.c:343
 asm_call_irq_on_stack+0xf/0x20
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x32/0x40 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:226 [inline]
 __irq_exit_rcu+0xb4/0xc0 kernel/softirq.c:420
 common_interrupt+0xb5/0x130 arch/x86/kernel/irq.c:239
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:620
 preempt_schedule_irq+0x3e/0x80 kernel/sched/core.c:5340
 irqentry_exit_cond_resched+0x30/0x40 kernel/entry/common.c:385
 irqentry_exit+0x2a/0x40 kernel/entry/common.c:415
 sysvec_apic_timer_interrupt+0x80/0x90 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:629
 native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline]
 arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline]
 kcsan_setup_watchpoint+0x1fc/0x4d0 kernel/kcsan/core.c:591
 __kernfs_remove+0x500/0x6a0 fs/kernfs/dir.c:1330
 kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1356
 sysfs_remove_group+0x17f/0x1a0 fs/sysfs/group.c:291
 sysfs_remove_groups+0x3b/0x80 fs/sysfs/group.c:313
 device_remove_groups drivers/base/core.c:2211 [inline]
 device_remove_attrs+0x7b/0xd0 drivers/base/core.c:2402
 device_del+0x3f8/0x8f0 drivers/base/core.c:3287
 netdev_unregister_kobject+0xec/0x100 net/core/net-sysfs.c:1952
 unregister_netdevice_many+0xbc0/0xf60 net/core/dev.c:10932
 vti6_exit_batch_net+0x183/0x1b0 net/ipv6/ip6_vti.c:1186
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x4dc/0x900 net/core/net_namespace.c:595
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x616/0xa70 kernel/workqueue.c:2421
 kthread+0x20b/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff88800a0476b0 of 8 bytes by task 8404 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1660 [inline]
 xas_next_marked include/linux/xarray.h:1691 [inline]
 find_get_pages_range_tag+0x35c/0x600 mm/filemap.c:2107
 pagevec_lookup_range_tag+0x37/0x50 mm/swap.c:1122
 __filemap_fdatawait_range+0xab/0x1b0 mm/filemap.c:519
 filemap_fdatawait_range mm/filemap.c:554 [inline]
 filemap_write_and_wait_range+0x119/0x2a0 mm/filemap.c:664
 filemap_write_and_wait include/linux/fs.h:2647 [inline]
 __sync_blockdev+0x51/0x70 fs/block_dev.c:513
 __sync_filesystem fs/sync.c:40 [inline]
 sync_filesystem+0x135/0x160 fs/sync.c:67
 ovl_sync_fs+0x9c/0xe0 fs/overlayfs/super.c:295
 __sync_filesystem fs/sync.c:39 [inline]
 sync_filesystem+0x112/0x160 fs/sync.c:67
 generic_shutdown_super+0x42/0x210 fs/super.c:448
 kill_anon_super+0x23/0x40 fs/super.c:1055
 deactivate_locked_super+0x6a/0xb0 fs/super.c:335
 deactivate_super+0x85/0x90 fs/super.c:366
 cleanup_mnt+0x277/0x2e0 fs/namespace.c:1118
 __cleanup_mnt+0x15/0x20 fs/namespace.c:1125
 task_work_run+0x8e/0x110 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x17c/0x1b0 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:294
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8404 Comm: syz-executor.1 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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