------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 21 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Modules linked in: CPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 5.19.0-next-20220811-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Code: e9 db fe ff ff 48 89 df e8 3c ee ca fd e9 8a fe ff ff e8 c2 95 7e fd 48 c7 c7 40 b8 48 8a c6 05 c5 2b cc 09 01 e8 4c ac 3c 05 <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 RSP: 0000:ffffc900001b7d10 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888011a49d80 RSI: ffffffff8161f1f8 RDI: fffff52000036f94 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000080000100 R11: 0000000000000001 R12: ffff88801faebb00 R13: ffff88801faebb28 R14: ffffc900001b7dc8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000000bc8e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] put_task_struct include/linux/sched/task.h:118 [inline] delayed_put_task_struct+0x2de/0x330 kernel/exit.c:177 rcu_do_batch kernel/rcu/tree.c:2245 [inline] rcu_core+0x7b5/0x1890 kernel/rcu/tree.c:2505 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571 run_ksoftirqd kernel/softirq.c:934 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:926 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306