EXT4-fs (loop2): mounting ext3 file system using the ext4 subsystem
EXT4-fs (loop2): 1 truncate cleaned up
EXT4-fs (loop2): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
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BUG: KCSAN: data-race in xas_find_marked / xas_set_mark

read-write to 0xffff88811b0c56c0 of 8 bytes by task 24088 on cpu 1:
 instrument_read_write include/linux/instrumented.h:56 [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:95 [inline]
 xas_set_mark+0x82/0x140 lib/xarray.c:893
 tag_pages_for_writeback+0xe3/0x2e0 mm/page-writeback.c:2348
 ext4_do_writepages+0x6b9/0x2840 fs/ext4/inode.c:2854
 ext4_writepages+0x18f/0x320 fs/ext4/inode.c:3019
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2554
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 filemap_write_and_wait_range+0x166/0x370 mm/filemap.c:684
 filemap_write_and_wait include/linux/pagemap.h:65 [inline]
 fiemap_prep+0x14d/0x170 fs/ioctl.c:194
 ext4_get_es_cache+0x1af/0x4f0 fs/ext4/extents.c:5218
 ext4_ioctl_get_es_cache fs/ext4/ioctl.c:1056 [inline]
 __ext4_ioctl fs/ext4/ioctl.c:1875 [inline]
 ext4_ioctl+0x1766/0x31b0 fs/ext4/ioctl.c:1922
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811b0c56c0 of 8 bytes by task 24068 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x213/0x620 lib/xarray.c:1510
 find_get_entry mm/filemap.c:2069 [inline]
 filemap_get_folios_tag+0xfa/0x510 mm/filemap.c:2337
 mpage_prepare_extent_to_map+0x328/0xc50 fs/ext4/inode.c:2632
 ext4_do_writepages+0x70f/0x2840 fs/ext4/inode.c:2871
 ext4_writepages+0x18f/0x320 fs/ext4/inode.c:3019
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2554
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 file_write_and_wait_range+0x178/0x2f0 mm/filemap.c:786
 generic_buffers_fsync_noflush+0x45/0x130 fs/buffer.c:606
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1aa/0x6b0 fs/ext4/fsync.c:147
 vfs_fsync_range+0xc5/0xe0 fs/sync.c:186
 generic_write_sync include/linux/fs.h:2640 [inline]
 ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:306
 ext4_file_write_iter+0x380/0xfa0 fs/ext4/file.c:-1
 do_iter_readv_writev+0x4fd/0x5a0 fs/read_write.c:-1
 vfs_writev+0x2e1/0x900 fs/read_write.c:1059
 do_pwritev fs/read_write.c:1155 [inline]
 __do_sys_pwritev2 fs/read_write.c:1213 [inline]
 __se_sys_pwritev2+0xfc/0x1c0 fs/read_write.c:1204
 __x64_sys_pwritev2+0x67/0x80 fs/read_write.c:1204
 x64_sys_call+0xe07/0x3020 arch/x86/include/generated/asm/syscalls_64.h:329
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00fffffffffffffd -> 0x00ffffffffffffe0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 24068 Comm: syz.2.4345 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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