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BUG: KCSAN: data-race in blk_mq_get_request / blk_mq_get_request

write to 0xffff888129ccf548 of 8 bytes by task 9248 on cpu 1:
 blk_mq_get_request+0x91a/0xba0 block/blk-mq.c:396
 blk_mq_make_request+0x2d7/0xf60 block/blk-mq.c:2001
 generic_make_request block/blk-core.c:1075 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1017
 submit_bio+0x8f/0x3a0 block/blk-core.c:1200
 submit_bio_wait+0xaf/0x150 block/bio.c:1077
 blkdev_issue_flush+0x12a/0x190 block/blk-flush.c:461
 ext4_sync_fs+0x321/0x470 fs/ext4/super.c:5261
 __sync_filesystem fs/sync.c:39 [inline]
 sync_filesystem fs/sync.c:67 [inline]
 sync_filesystem+0x15d/0x1a0 fs/sync.c:48
 ovl_sync_fs+0x89/0xa0 fs/overlayfs/super.c:277
 __sync_filesystem fs/sync.c:39 [inline]
 sync_filesystem fs/sync.c:67 [inline]
 sync_filesystem+0x15d/0x1a0 fs/sync.c:48
 generic_shutdown_super+0x68/0x270 fs/super.c:448
 kill_anon_super+0x28/0x50 fs/super.c:1108
 deactivate_locked_super+0x5d/0xb0 fs/super.c:335
 deactivate_super fs/super.c:366 [inline]
 deactivate_super+0xca/0xe0 fs/super.c:362
 cleanup_mnt+0x27a/0x330 fs/namespace.c:1102
 __cleanup_mnt+0x1c/0x30 fs/namespace.c:1109
 task_work_run+0xba/0x120 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888129ccf548 of 8 bytes by task 9506 on cpu 0:
 blk_mq_get_request+0x907/0xba0 block/blk-mq.c:396
 blk_mq_make_request+0x2d7/0xf60 block/blk-mq.c:2001
 generic_make_request block/blk-core.c:1075 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1017
 submit_bio+0x8f/0x3a0 block/blk-core.c:1200
 submit_bh_wbc+0x40d/0x460 fs/buffer.c:3063
 __block_write_full_page+0x4f5/0x8e0 fs/buffer.c:1801
 block_write_full_page+0x1ba/0x1d0 fs/buffer.c:2987
 blkdev_writepage+0x2b/0x40 fs/block_dev.c:610
 __writepage+0x3d/0xb0 mm/page-writeback.c:2303
 write_cache_pages+0x400/0xa10 mm/page-writeback.c:2238
 generic_writepages mm/page-writeback.c:2329 [inline]
 generic_writepages+0x79/0xc0 mm/page-writeback.c:2318
 blkdev_writepages+0x23/0x40 fs/block_dev.c:2074
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1bb/0x220 mm/filemap.c:421
 filemap_write_and_wait_range mm/filemap.c:654 [inline]
 filemap_write_and_wait_range+0xad/0x140 mm/filemap.c:648
 filemap_write_and_wait include/linux/fs.h:2767 [inline]
 __sync_blockdev+0x62/0x90 fs/block_dev.c:492
 __sync_filesystem fs/sync.c:40 [inline]
 sync_filesystem fs/sync.c:67 [inline]
 sync_filesystem+0x17b/0x1a0 fs/sync.c:48
 ovl_sync_fs+0x89/0xa0 fs/overlayfs/super.c:277
 __sync_filesystem fs/sync.c:39 [inline]
 sync_filesystem fs/sync.c:67 [inline]
 sync_filesystem+0x15d/0x1a0 fs/sync.c:48
 generic_shutdown_super+0x68/0x270 fs/super.c:448
 kill_anon_super+0x28/0x50 fs/super.c:1108
 deactivate_locked_super+0x5d/0xb0 fs/super.c:335
 deactivate_super fs/super.c:366 [inline]
 deactivate_super+0xca/0xe0 fs/super.c:362
 cleanup_mnt+0x27a/0x330 fs/namespace.c:1102
 __cleanup_mnt+0x1c/0x30 fs/namespace.c:1109
 task_work_run+0xba/0x120 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9506 Comm: syz-executor.5 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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