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BUG: KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert_extent

write to 0xffff888148917576 of 2 bytes by task 7384 on cpu 0:
 le16_add_cpu include/linux/byteorder/generic.h:146 [inline]
 ext4_ext_grow_indepth fs/ext4/extents.c:1338 [inline]
 ext4_ext_create_new_leaf fs/ext4/extents.c:1388 [inline]
 ext4_ext_insert_extent+0xd50/0x2d90 fs/ext4/extents.c:2062
 ext4_ext_map_blocks+0x1714/0x1ff0 fs/ext4/extents.c:4271
 ext4_map_blocks+0x71e/0xf00 fs/ext4/inode.c:637
 _ext4_get_block+0x103/0x290 fs/ext4/inode.c:793
 ext4_get_block_unwritten+0x26/0x30 fs/ext4/inode.c:824
 __block_write_begin_int+0x4c5/0x1080 fs/buffer.c:2006
 __block_write_begin+0x2b/0x40 fs/buffer.c:2056
 ext4_write_begin+0x41e/0xcc0
 ext4_da_write_begin+0x208/0x7f0 fs/ext4/inode.c:2966
 generic_perform_write+0x1b8/0x3e0 mm/filemap.c:3770
 ext4_buffered_write_iter+0x305/0x400 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x7bc/0x900 fs/read_write.c:594
 ksys_write+0xd9/0x190 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:656
 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 0xffff888148917576 of 2 bytes by task 16583 on cpu 1:
 ext_depth fs/ext4/ext4_extents.h:194 [inline]
 ext4_ext_index_trans_blocks+0x86/0xb0 fs/ext4/extents.c:2364
 ext4_index_trans_blocks fs/ext4/inode.c:5632 [inline]
 ext4_meta_trans_blocks fs/ext4/inode.c:5658 [inline]
 ext4_chunk_trans_blocks+0x96/0x1a0 fs/ext4/inode.c:5716
 ext4_convert_unwritten_extents+0x9a/0x2d0 fs/ext4/extents.c:4760
 ext4_convert_unwritten_io_end_vec+0xa4/0x130 fs/ext4/extents.c:4812
 ext4_end_io_end fs/ext4/page-io.c:184 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:257 [inline]
 ext4_end_io_rsv_work+0x198/0x360 fs/ext4/page-io.c:271
 process_one_work+0x402/0x910 kernel/workqueue.c:2297
 worker_thread+0x636/0xae0 kernel/workqueue.c:2444
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

value changed: 0x0000 -> 0x0001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16583 Comm: kworker/u4:8 Tainted: G        W         5.15.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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