------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 9 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 6.16.0-syzkaller-12187-g0227b49b5027 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: md_misc mddev_delayed_delete RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Code: ff 89 de e8 a8 6e d8 fc 84 db 0f 85 66 ff ff ff e8 bb 73 d8 fc c6 05 c2 75 b0 0b 01 90 48 c7 c7 00 93 15 8c e8 47 12 97 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 98 73 d8 fc 0f b6 1d 9d 75 b0 0b 31 RSP: 0018:ffffc900000e7c10 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817a3358 RDX: ffff88801e28c880 RSI: ffffffff817a3365 RDI: 0000000000000001 RBP: ffff88803579a130 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff88803579a134 R13: dffffc0000000000 R14: ffff88803579a130 R15: ffffc900000e7d10 FS: 0000000000000000(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000062c0 CR3: 00000000480b6000 CR4: 00000000003526f0 Call Trace: __refcount_sub_and_test include/linux/refcount.h:400 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] kref_put include/linux/kref.h:64 [inline] kobject_put+0x230/0x5a0 lib/kobject.c:737 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245