==================================================================
BUG: KCSAN: data-race in clean_buffers / recalc_bh_state

read to 0xffffffff8625ced0 of 4 bytes by task 833 on cpu 1:
 clean_buffers fs/mpage.c:482 [inline]
 clean_buffers+0x104/0x1b0 fs/mpage.c:461
 __mpage_writepage+0xad1/0xe70 fs/mpage.c:657
 write_cache_pages+0x47a/0xb40 mm/page-writeback.c:2238
 mpage_writepages+0xab/0x180 fs/mpage.c:730
 fat_writepages+0x2e/0x40 fs/fat/inode.c:204
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __writeback_single_inode+0xaf/0x8e0 fs/fs-writeback.c:1452
 writeback_sb_inodes+0x4ba/0xa50 fs/fs-writeback.c:1716
 wb_writeback+0x1f9/0x6a0 fs/fs-writeback.c:1892
 wb_do_writeback fs/fs-writeback.c:2037 [inline]
 wb_workfn+0x22e/0x970 fs/fs-writeback.c:2078
 process_one_work+0x3d4/0x890 kernel/workqueue.c:2264
 worker_thread+0xa0/0x800 kernel/workqueue.c:2410
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

write to 0xffffffff8625ced0 of 4 bytes by task 7726 on cpu 0:
 recalc_bh_state fs/buffer.c:3403 [inline]
 recalc_bh_state+0x124/0x150 fs/buffer.c:3393
 free_buffer_head+0x96/0xf0 fs/buffer.c:3426
 try_to_free_buffers+0x1a4/0x2b0 fs/buffer.c:3338
 try_to_release_page+0x188/0x1c0 mm/filemap.c:3506
 block_invalidatepage+0x300/0x320 fs/buffer.c:1541
 do_invalidatepage mm/truncate.c:163 [inline]
 truncate_cleanup_page+0xc2/0x240 mm/truncate.c:185
 truncate_inode_pages_range+0x556/0x1120 mm/truncate.c:365
 truncate_inode_pages mm/truncate.c:476 [inline]
 truncate_inode_pages_final+0x67/0x90 mm/truncate.c:527
 fat_evict_inode+0x2b/0x160 fs/fat/inode.c:652
 evict+0x244/0x410 fs/inode.c:574
 dispose_list+0xf5/0x150 fs/inode.c:609
 evict_inodes+0x2b1/0x300 fs/inode.c:659
 generic_shutdown_super+0xa6/0x260 fs/super.c:454
 kill_block_super+0x60/0xb0 fs/super.c:1442
 deactivate_locked_super+0x64/0xb0 fs/super.c:335
 deactivate_super fs/super.c:366 [inline]
 deactivate_super+0xca/0xe0 fs/super.c:362
 cleanup_mnt+0x27f/0x330 fs/namespace.c:1102
 __cleanup_mnt+0x1f/0x30 fs/namespace.c:1109
 task_work_run+0xf6/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x384/0x3a0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7726 Comm: syz-executor.5 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================