==================================================================
BUG: KCSAN: data-race in __writeback_single_inode / ext4_set_iomap

write to 0xffff8881363262b0 of 8 bytes by task 8492 on cpu 1:
 __writeback_single_inode+0x1e9/0x440 fs/fs-writeback.c:1652
 writeback_single_inode+0x17b/0x3e0 fs/fs-writeback.c:1729
 sync_inode_metadata+0x57/0x80 fs/fs-writeback.c:2748
 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline]
 ext4_sync_file+0x359/0x670 fs/ext4/fsync.c:170
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2955 [inline]
 ext4_buffered_write_iter+0x3af/0x400 fs/ext4/file.c:277
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2163 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:729
 do_iter_write+0x192/0x5c0 fs/read_write.c:855
 vfs_iter_write+0x4c/0x70 fs/read_write.c:896
 iter_file_splice_write+0x43a/0x790 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+0x106/0x190 fs/splice.c:979
 do_sendfile+0x63e/0xbb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1314 [inline]
 __se_sys_sendfile64 fs/read_write.c:1300 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1300
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881363262b0 of 8 bytes by task 8485 on cpu 0:
 ext4_inode_datasync_dirty fs/ext4/inode.c:3336 [inline]
 ext4_set_iomap+0x17c/0x460 fs/ext4/inode.c:3351
 ext4_iomap_begin+0x5e1/0x630 fs/ext4/inode.c:3490
 iomap_iter+0x39c/0x470 fs/iomap/iter.c:74
 __iomap_dio_rw+0x698/0x1010 fs/iomap/direct-io.c:568
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:649
 ext4_dio_write_iter fs/ext4/file.c:568 [inline]
 ext4_file_write_iter+0xa59/0x11f0 fs/ext4/file.c:678
 call_write_iter include/linux/fs.h:2163 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:729
 do_iter_write+0x192/0x5c0 fs/read_write.c:855
 vfs_iter_write+0x4c/0x70 fs/read_write.c:896
 iter_file_splice_write+0x43a/0x790 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+0x106/0x190 fs/splice.c:979
 do_sendfile+0x63e/0xbb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1314 [inline]
 __se_sys_sendfile64 fs/read_write.c:1300 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1300
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000084 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8485 Comm: syz-executor.4 Not tainted 5.15.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================