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BUG: KCSAN: data-race in inode_add_bytes / udf_update_inode

write to 0xffff8880434e5490 of 8 bytes by task 26958 on cpu 0:
 __inode_add_bytes fs/stat.c:694 [inline]
 inode_add_bytes+0x49/0xe0 fs/stat.c:707
 udf_prealloc_blocks+0x7f9/0x890 fs/udf/balloc.c:694
 udf_prealloc_extents fs/udf/inode.c:1022 [inline]
 inode_getblk fs/udf/inode.c:883 [inline]
 udf_get_block+0x1252/0x2100 fs/udf/inode.c:443
 __block_write_begin_int+0x4a2/0x1090 fs/buffer.c:2011
 __block_write_begin fs/buffer.c:2061 [inline]
 block_write_begin+0x4f/0x1b0 fs/buffer.c:2120
 udf_write_begin+0x39/0x190 fs/udf/inode.c:212
 generic_perform_write+0x196/0x3a0 mm/filemap.c:3412
 __generic_file_write_iter+0x15c/0x340 mm/filemap.c:3541
 udf_file_write_iter+0x220/0x2f0 fs/udf/file.c:168
 call_write_iter include/linux/fs.h:1901 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_writev fs/read_write.c:939 [inline]
 do_pwritev+0x20d/0x410 fs/read_write.c:1036
 __do_sys_pwritev fs/read_write.c:1083 [inline]
 __se_sys_pwritev fs/read_write.c:1078 [inline]
 __x64_sys_pwritev+0x54/0x60 fs/read_write.c:1078
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880434e5490 of 8 bytes by task 24 on cpu 1:
 udf_update_inode+0x561/0xfb0 fs/udf/inode.c:1771
 udf_write_inode+0x37/0x40 fs/udf/inode.c:1662
 write_inode+0x8c/0x1f0 fs/fs-writeback.c:1320
 __writeback_single_inode+0x2a3/0x500 fs/fs-writeback.c:1518
 writeback_sb_inodes+0x6a7/0xff0 fs/fs-writeback.c:1723
 wb_writeback+0x27d/0x660 fs/fs-writeback.c:1896
 wb_do_writeback+0x101/0x5d0 fs/fs-writeback.c:2041
 wb_workfn+0xc8/0x430 fs/fs-writeback.c:2082
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24 Comm: kworker/u4:1 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-7:5)
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