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BUG: KCSAN: data-race in __mark_inode_dirty / ext4_set_iomap

write to 0xffff88800edfba50 of 8 bytes by task 11382 on cpu 1:
 __mark_inode_dirty+0x212/0x740 fs/fs-writeback.c:2290
 mark_inode_dirty_sync include/linux/fs.h:2174 [inline]
 dquot_claim_block include/linux/quotaops.h:364 [inline]
 ext4_da_update_reserve_space+0x160/0x2e0 fs/ext4/inode.c:369
 ext4_ext_map_blocks+0x19d9/0x1fc0 fs/ext4/extents.c:4291
 ext4_map_blocks+0x6c3/0xf20 fs/ext4/inode.c:625
 mpage_map_one_extent+0x10d/0x390 fs/ext4/inode.c:2376
 mpage_map_and_submit_extent fs/ext4/inode.c:2429 [inline]
 ext4_writepages+0xa2c/0x1e10 fs/ext4/inode.c:2781
 do_writepages+0x7b/0x150 mm/page-writeback.c:2352
 __filemap_fdatawrite_range+0x19d/0x1d0 mm/filemap.c:422
 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:761
 ext4_sync_file+0xfc/0x690 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2725 [inline]
 ext4_buffered_write_iter+0x363/0x3b0 fs/ext4/file.c:276
 ext4_file_write_iter+0x480/0x10b0 fs/ext4/file.c:501
 call_write_iter include/linux/fs.h:1887 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:721
 do_iter_write+0x112/0x4b0 fs/read_write.c:847
 vfs_iter_write+0x4c/0x70 fs/read_write.c:888
 iter_file_splice_write+0x42a/0x780 fs/splice.c:769
 do_splice_from fs/splice.c:865 [inline]
 direct_splice_actor+0x95/0x150 fs/splice.c:1035
 splice_direct_to_actor+0x365/0x660 fs/splice.c:990
 do_splice_direct+0xf5/0x170 fs/splice.c:1078
 do_sendfile+0x574/0xb70 fs/read_write.c:1238
 __do_sys_sendfile64 fs/read_write.c:1299 [inline]
 __se_sys_sendfile64 fs/read_write.c:1285 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1285
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88800edfba50 of 8 bytes by task 11387 on cpu 0:
 ext4_inode_datasync_dirty fs/ext4/inode.c:3305 [inline]
 ext4_set_iomap+0x136/0x3c0 fs/ext4/inode.c:3320
 ext4_iomap_begin+0x5cc/0x620 fs/ext4/inode.c:3447
 iomap_apply+0x8d/0x4a0 fs/iomap/apply.c:46
 __iomap_dio_rw+0x448/0x9b0 fs/iomap/direct-io.c:517
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:605
 ext4_dio_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0x3b6/0x420 fs/ext4/file.c:129
 call_read_iter include/linux/fs.h:1881 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:889 [inline]
 splice_direct_to_actor+0x2ab/0x660 fs/splice.c:969
 do_splice_direct+0xf5/0x170 fs/splice.c:1078
 do_sendfile+0x574/0xb70 fs/read_write.c:1238
 __do_sys_sendfile64 fs/read_write.c:1299 [inline]
 __se_sys_sendfile64 fs/read_write.c:1285 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1285
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11387 Comm: syz-executor.0 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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