------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28, CPU#1: kworker/1:0/24 Modules linked in: CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted 6.16.0-next-20250731-syzkaller #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+0x11a/0x1d0 lib/refcount.c:28 Code: 40 49 04 8c e8 17 f7 b3 fc 90 0f 0b 90 90 eb d7 e8 1b 60 f0 fc c6 05 8d a8 fd 0a 01 90 48 c7 c7 a0 49 04 8c e8 f7 f6 b3 fc 90 <0f> 0b 90 90 eb b7 e8 fb 5f f0 fc c6 05 6a a8 fd 0a 01 90 48 c7 c7 RSP: 0018:ffffc900001e7a68 EFLAGS: 00010246 RAX: 91b7c91a28ea1700 RBX: 0000000000000003 RCX: ffff88801da98000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002 RBP: ffffc900001e7c70 R08: ffff8880b8724253 R09: 1ffff110170e484a R10: dffffc0000000000 R11: ffffed10170e484b R12: ffff8880b87396c0 R13: ffff88801d2d2e18 R14: ffff888023e38130 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812590a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30a16ff8 CR3: 000000007750c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 000000000000000a DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245