syzbot

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BUG: KCSAN: data-race in __xa_set_mark / xas_find_marked

read-write to 0xffff88812ba5a8e8 of 8 bytes by task 11963 on cpu 1:
 instrument_read_write include/linux/instrumented.h:58 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:84 [inline]
 ___test_and_set_bit include/asm-generic/bitops/instrumented-non-atomic.h:99 [inline]
 node_set_mark lib/xarray.c:93 [inline]
 xas_set_mark lib/xarray.c:887 [inline]
 __xa_set_mark+0xe0/0x1a0 lib/xarray.c:1906
 __folio_mark_dirty+0xfb/0x130 mm/page-writeback.c:2729
 __set_page_dirty include/linux/pagemap.h:1052 [inline]
 mark_buffer_dirty+0x152/0x390 fs/buffer.c:1105
 __block_commit_write+0x11d/0x1c0 fs/buffer.c:2065
 block_write_end fs/buffer.c:2144 [inline]
 generic_write_end+0x81/0x350 fs/buffer.c:2158
 ext4_da_write_end+0x26c/0x620 fs/ext4/inode.c:3175
 generic_perform_write+0x264/0x3f0 mm/filemap.c:3783
 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:285
 ext4_file_write_iter+0x2bb/0x11b0
 call_write_iter include/linux/fs.h:2189 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x468/0x760 fs/read_write.c:584
 ksys_write+0xe8/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88812ba5a8e8 of 8 bytes by task 8046 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1704 [inline]
 xas_find_marked+0x22f/0x6a0 lib/xarray.c:1356
 find_get_entry mm/filemap.c:2006 [inline]
 find_get_pages_range_tag+0x102/0x420 mm/filemap.c:2311
 pagevec_lookup_range_tag+0x37/0x50 mm/swap.c:1126
 mpage_prepare_extent_to_map+0x1be/0xcf0 fs/ext4/inode.c:2618
 ext4_do_writepages+0x6dd/0x1e70 fs/ext4/inode.c:2830
 ext4_writepages+0x11b/0x240 fs/ext4/inode.c:2965
 do_writepages+0x1db/0x350 mm/page-writeback.c:2581
 __writeback_single_inode+0x81/0x590 fs/fs-writeback.c:1598
 writeback_sb_inodes+0x4dd/0xa30 fs/fs-writeback.c:1889
 __writeback_inodes_wb+0xa0/0x1b0 fs/fs-writeback.c:1960
 wb_writeback+0x280/0x650 fs/fs-writeback.c:2065
 wb_check_start_all fs/fs-writeback.c:2187 [inline]
 wb_do_writeback+0x418/0x600 fs/fs-writeback.c:2213
 wb_workfn+0x88/0x260 fs/fs-writeback.c:2246
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

value changed: 0x0180000000000000 -> 0x0780000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8046 Comm: kworker/u4:8 Tainted: G        W          6.2.0-rc6-syzkaller-00003-g22b8077d0fce-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
Workqueue: writeback wb_workfn (flush-8:0)
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