syzbot

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BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked

read-write to 0xffff88810a6cf478 of 8 bytes by task 4058 on cpu 0:
 instrument_read_write include/linux/instrumented.h:57 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:84 [inline]
 ___test_and_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:114 [inline]
 node_clear_mark lib/xarray.c:100 [inline]
 xas_clear_mark+0x8f/0x170 lib/xarray.c:916
 __folio_start_writeback+0x3e1/0x5d0 mm/page-writeback.c:2998
 set_page_writeback+0x3d/0xe0 mm/folio-compat.c:56
 ext4_bio_write_page+0x119/0xb60 fs/ext4/page-io.c:451
 mpage_submit_page fs/ext4/inode.c:2114 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2359 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2498 [inline]
 ext4_writepages+0x1020/0x1cf0 fs/ext4/inode.c:2827
 do_writepages+0x1db/0x350 mm/page-writeback.c:2468
 filemap_fdatawrite_wbc+0xd6/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 file_write_and_wait_range+0xd6/0x170 mm/filemap.c:773
 ext4_sync_file+0x105/0x6d0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2869 [inline]
 ext4_buffered_write_iter+0x398/0x3e0 fs/ext4/file.c:277
 ext4_file_write_iter+0x2e3/0x1210
 call_write_iter include/linux/fs.h:2187 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x468/0x760 fs/read_write.c:578
 ksys_write+0xe8/0x1a0 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write fs/read_write.c:640 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:640
 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 0xffff88810a6cf478 of 8 bytes by task 4070 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1704 [inline]
 xas_find_marked+0x22f/0x6a0 lib/xarray.c:1356
 find_get_entry mm/filemap.c:2010 [inline]
 find_get_pages_range_tag+0x103/0x4f0 mm/filemap.c:2284
 pagevec_lookup_range_tag+0x37/0x50 mm/swap.c:1062
 mpage_prepare_extent_to_map+0x1a4/0xa50 fs/ext4/inode.c:2588
 ext4_writepages+0x6b2/0x1cf0 fs/ext4/inode.c:2781
 do_writepages+0x1db/0x350 mm/page-writeback.c:2468
 filemap_fdatawrite_wbc+0xd6/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 filemap_write_and_wait_range+0xc2/0x1d0 mm/filemap.c:673
 filemap_write_and_wait include/linux/pagemap.h:60 [inline]
 ext4_ioctl_setflags fs/ext4/ioctl.c:635 [inline]
 ext4_fileattr_set+0x581/0xde0 fs/ext4/ioctl.c:1001
 vfs_fileattr_set+0x56b/0x5d0 fs/ioctl.c:696
 do_vfs_ioctl+0x1010/0x1390
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 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

value changed: 0xffffffffffffffff -> 0xfffffffffffffffc

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4070 Comm: syz-executor.4 Not tainted 6.0.0-rc7-syzkaller-00029-g3800a713b607-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
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