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BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked

read-write to 0xffff8881006b8238 of 8 bytes by task 11378 on cpu 1:
 instrument_read_write include/linux/instrumented.h:55 [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:102 [inline]
 xas_clear_mark+0x91/0x180 lib/xarray.c:922
 __folio_start_writeback+0x2e7/0x440 mm/page-writeback.c:3092
 __block_write_full_folio+0x53a/0x8f0 fs/buffer.c:1934
 block_write_full_folio+0x2c2/0x2e0 fs/buffer.c:-1
 blkdev_writepages+0x88/0x100 block/fops.c:483
 do_writepages+0x1c3/0x310 mm/page-writeback.c:2636
 filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
 __filemap_fdatawrite_range mm/filemap.c:419 [inline]
 filemap_write_and_wait_range+0x144/0x340 mm/filemap.c:691
 filemap_write_and_wait include/linux/pagemap.h:68 [inline]
 sync_blockdev+0x35/0x50 block/bdev.c:260
 dquot_quota_sync+0xdd/0x330 fs/quota/dquot.c:759
 quota_sync_one+0x86/0xb0 fs/quota/quota.c:60
 __iterate_supers+0x10d/0x1f0 fs/super.c:924
 iterate_supers+0x1f/0x30 fs/super.c:939
 quota_sync_all fs/quota/quota.c:69 [inline]
 __do_sys_quotactl fs/quota/quota.c:938 [inline]
 __se_sys_quotactl+0x269/0x670 fs/quota/quota.c:917
 __x64_sys_quotactl+0x55/0x70 fs/quota/quota.c:917
 x64_sys_call+0x2886/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:180
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881006b8238 of 8 bytes by task 11376 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x218/0x620 lib/xarray.c:1510
 find_get_entry+0x5d/0x380 mm/filemap.c:2038
 filemap_get_folios_tag+0x13b/0x210 mm/filemap.c:2306
 writeback_get_folio mm/page-writeback.c:2463 [inline]
 writeback_iter+0x4bb/0x820 mm/page-writeback.c:2564
 blkdev_writepages+0x69/0x100 block/fops.c:482
 do_writepages+0x1c3/0x310 mm/page-writeback.c:2636
 filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
 __filemap_fdatawrite_range mm/filemap.c:419 [inline]
 filemap_write_and_wait_range+0x144/0x340 mm/filemap.c:691
 filemap_write_and_wait include/linux/pagemap.h:68 [inline]
 sync_blockdev+0x35/0x50 block/bdev.c:260
 dquot_quota_sync+0xdd/0x330 fs/quota/dquot.c:759
 quota_sync_one+0x86/0xb0 fs/quota/quota.c:60
 __iterate_supers+0x10d/0x1f0 fs/super.c:924
 iterate_supers+0x1f/0x30 fs/super.c:939
 quota_sync_all fs/quota/quota.c:69 [inline]
 __do_sys_quotactl fs/quota/quota.c:938 [inline]
 __se_sys_quotactl+0x269/0x670 fs/quota/quota.c:917
 __x64_sys_quotactl+0x55/0x70 fs/quota/quota.c:917
 x64_sys_call+0x2886/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:180
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000001 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11376 Comm: syz.3.1780 Tainted: G        W           6.16.0-rc4-syzkaller-00308-ga79a588fc176 #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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