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BUG: KCSAN: data-race in has_bh_in_lru / invalidate_bh_lrus_cpu

write to 0xffff888237c42f10 of 8 bytes by task 14928 on cpu 0:
 __invalidate_bh_lrus fs/buffer.c:1393 [inline]
 invalidate_bh_lrus_cpu+0xad/0xe0 fs/buffer.c:1434
 lru_add_drain_cpu+0x243/0x270 mm/swap.c:645
 lru_add_drain mm/swap.c:724 [inline]
 __pagevec_release+0x57/0xa0 mm/swap.c:989
 pagevec_release include/linux/pagevec.h:81 [inline]
 write_cache_pages+0x6b7/0x810 mm/page-writeback.c:2288
 mpage_writepages+0x6d/0x120 fs/mpage.c:712
 fat_writepages+0x20/0x30 fs/fat/inode.c:205
 do_writepages+0x7b/0x150 mm/page-writeback.c:2355
 __filemap_fdatawrite_range mm/filemap.c:413 [inline]
 filemap_write_and_wait_range+0x20a/0x390 mm/filemap.c:686
 generic_file_direct_write+0xcc/0x4f0 mm/filemap.c:3534
 __generic_file_write_iter+0x1a9/0x300 mm/filemap.c:3740
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3815
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c42f10 of 8 bytes by task 1788 on cpu 1:
 has_bh_in_lru+0x31/0x1c0 fs/buffer.c:1415
 smp_call_function_many_cond+0x226/0x620 kernel/smp.c:915
 on_each_cpu_cond_mask+0x31/0x40 kernel/smp.c:1133
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x26/0x30 fs/buffer.c:1424
 kill_bdev fs/block_dev.c:85 [inline]
 blkdev_flush_mapping+0xcf/0x240 fs/block_dev.c:1243
 blkdev_put_whole fs/block_dev.c:1277 [inline]
 blkdev_put+0x3a4/0x4e0 fs/block_dev.c:1576
 kill_block_super+0x7b/0x90 fs/super.c:1398
 deactivate_locked_super+0x65/0xd0 fs/super.c:335
 deactivate_super+0x85/0x90 fs/super.c:366
 cleanup_mnt+0x267/0x2d0 fs/namespace.c:1136
 __cleanup_mnt+0x15/0x20 fs/namespace.c:1143
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302
 do_syscall_64+0x49/0x90 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff888106ee5dd0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1788 Comm: syz-executor.0 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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