==================================================================
BUG: KCSAN: data-race in __mark_inode_dirty / move_expired_inodes

read-write to 0xffff888100631d38 of 4 bytes by task 5659 on cpu 0:
 move_expired_inodes+0x17a/0x400 fs/fs-writeback.c:1457
 queue_io+0xd9/0x2c0 fs/fs-writeback.c:1509
 wb_writeback+0x226/0x5c0 fs/fs-writeback.c:2152
 wb_check_start_all fs/fs-writeback.c:2284 [inline]
 wb_do_writeback fs/fs-writeback.c:2310 [inline]
 wb_workfn+0x4c9/0x910 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888100631d38 of 4 bytes by task 21023 on cpu 1:
 __mark_inode_dirty+0x18e/0x760 fs/fs-writeback.c:2549
 mark_buffer_dirty+0x133/0x210 fs/buffer.c:1212
 __ext4_handle_dirty_metadata+0x200/0x470 fs/ext4/ext4_jbd2.c:388
 ext4_mb_mark_context+0x86f/0x920 fs/ext4/mballoc.c:4067
 ext4_mb_mark_diskspace_used+0x1eb/0x3c0 fs/ext4/mballoc.c:4131
 ext4_mb_new_blocks+0xa62/0x2050 fs/ext4/mballoc.c:6233
 ext4_ext_map_blocks+0xfe6/0x3620 fs/ext4/extents.c:4379
 ext4_map_create_blocks fs/ext4/inode.c:520 [inline]
 ext4_map_blocks+0x5ab/0xd00 fs/ext4/inode.c:706
 _ext4_get_block+0x10a/0x350 fs/ext4/inode.c:785
 ext4_get_block_unwritten+0x2a/0xb0 fs/ext4/inode.c:818
 ext4_block_write_begin+0x303/0x970 fs/ext4/inode.c:1067
 ext4_write_begin+0x43c/0xc30 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x1e8/0x580 fs/ext4/inode.c:2932
 generic_perform_write+0x181/0x490 mm/filemap.c:4103
 ext4_buffered_write_iter+0x1ee/0x3c0 fs/ext4/file.c:299
 ext4_file_write_iter+0x383/0xf00 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x4a0/0x8d0 fs/read_write.c:684
 ksys_write+0xda/0x1a0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:747 [inline]
 __se_sys_write fs/read_write.c:744 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:744
 x64_sys_call+0x2cdd/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000020 -> 0x00010022

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 21023 Comm: syz.9.5743 Not tainted 6.15.0-rc7-syzkaller-00007-g4a95bc121ccd #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================