------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 3 PID: 6041 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 3 UID: 0 PID: 6041 Comm: kworker/3:4 Not tainted 6.16.0-syzkaller-11895-gcca7a0aae895 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: md_misc mddev_delayed_delete RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Code: ff 89 de e8 48 39 db fc 84 db 0f 85 66 ff ff ff e8 5b 3e db fc c6 05 61 c2 b3 0b 01 90 48 c7 c7 80 84 15 8c e8 b7 2f 9a fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 38 3e db fc 0f b6 1d 3c c2 b3 0b 31 RSP: 0018:ffffc9000371fc10 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817a02c8 RDX: ffff8880231da440 RSI: ffffffff817a02d5 RDI: 0000000000000001 RBP: ffff888065864130 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888065864134 R13: dffffc0000000000 R14: ffff888065864130 R15: ffffc9000371fd10 FS: 0000000000000000(0000) GS:ffff8880977cc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002e4fcffc CR3: 00000000560f1000 CR4: 0000000000352ef0 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+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245