loop1: detected capacity change from 0 to 8192
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BUG: KCSAN: data-race in __mark_inode_dirty / move_expired_inodes

read-write to 0xffff8881005f0a80 of 4 bytes by task 2293 on cpu 1:
 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:3236 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff8881005f0a80 of 4 bytes by task 13042 on cpu 0:
 __mark_inode_dirty+0x18e/0x760 fs/fs-writeback.c:2549
 mark_buffer_dirty+0x133/0x210 fs/buffer.c:1209
 mark_buffer_dirty_inode+0x4c/0x1c0 fs/buffer.c:683
 fat_mirror_bhs+0x234/0x320 fs/fat/fatent.c:398
 fat_ent_write+0xd0/0xe0 fs/fat/fatent.c:423
 fat_chain_add+0x15d/0x440 fs/fat/misc.c:136
 fat_add_cluster fs/fat/inode.c:112 [inline]
 __fat_get_block fs/fat/inode.c:154 [inline]
 fat_get_block+0x46c/0x5e0 fs/fat/inode.c:189
 __block_write_begin_int+0x400/0xf90 fs/buffer.c:2145
 block_write_begin fs/buffer.c:2256 [inline]
 cont_write_begin+0x5fc/0x970 fs/buffer.c:2594
 fat_write_begin+0x4f/0xe0 fs/fat/inode.c:229
 generic_perform_write+0x181/0x490 mm/filemap.c:4175
 __generic_file_write_iter+0x9e/0x120 mm/filemap.c:4292
 generic_file_write_iter+0x8d/0x2f0 mm/filemap.c:4318
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x527/0x960 fs/read_write.c:686
 ksys_write+0xda/0x1a0 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:746
 x64_sys_call+0x27fe/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:2
 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: 0x00000020 -> 0x00010022

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13042 Comm: syz.1.3411 Not tainted 6.17.0-rc1-syzkaller-00038-g0cc53520e68b #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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