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BUG: KCSAN: data-race in has_bh_in_lru / invalidate_bh_lrus_cpu

write to 0xffff888237d42f10 of 8 bytes by task 11412 on cpu 1:
 __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]
 mpage_prepare_extent_to_map+0x5e5/0x640 fs/ext4/inode.c:2638
 ext4_writepages+0x9d8/0x1d10 fs/ext4/inode.c:2798
 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
 __iomap_dio_rw+0x4cd/0xa60 fs/iomap/direct-io.c:533
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:649
 ext4_dio_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0x21a/0x290 fs/ext4/file.c:128
 call_read_iter include/linux/fs.h:2108 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 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 0xffff888237d42f10 of 8 bytes by task 11473 on cpu 0:
 has_bh_in_lru+0x31/0x1c0 fs/buffer.c:1415
 __lru_add_drain_all+0x25b/0x3e0 mm/swap.c:834
 lru_add_drain_all+0xc/0x10 mm/swap.c:850
 invalidate_bdev+0x50/0x70 fs/block_dev.c:96
 __loop_clr_fd+0x566/0x8f0 drivers/block/loop.c:1402
 loop_clr_fd drivers/block/loop.c:1496 [inline]
 lo_ioctl+0xa48/0x1340 drivers/block/loop.c:1852
 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585
 block_ioctl+0x6d/0x80 fs/block_dev.c:1604
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 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

value changed: 0x0000000000000000 -> 0xffff888102316f70

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11473 Comm: syz-executor.2 Not tainted 5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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