[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.15.195' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 688.684150][T10889] ------------[ cut here ]------------ executing program [ 688.726201][T10889] refcount_t: underflow; use-after-free. [ 688.762776][T10889] WARNING: CPU: 0 PID: 10889 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 688.824902][T10889] Kernel panic - not syncing: panic_on_warn set ... [ 688.831520][T10889] CPU: 0 PID: 10889 Comm: io_wqe_worker-1 Not tainted 5.9.0-rc6-syzkaller #0 [ 688.840282][T10889] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 688.850353][T10889] Call Trace: [ 688.853710][T10889] dump_stack+0x198/0x1fd [ 688.858122][T10889] panic+0x382/0x7fb [ 688.862016][T10889] ? __warn_printk+0xf3/0xf3 [ 688.866614][T10889] ? refcount_warn_saturate+0x1d1/0x1e0 [ 688.872239][T10889] ? __collapse_huge_page_isolate+0x12d2/0x1980 [ 688.878502][T10889] ? refcount_warn_saturate+0x1d1/0x1e0 [ 688.884048][T10889] ? __warn.cold+0x5/0x4b [ 688.888636][T10889] ? __warn+0xd6/0x1f2 [ 688.892707][T10889] ? refcount_warn_saturate+0x1d1/0x1e0 [ 688.898255][T10889] __warn.cold+0x20/0x4b [ 688.902563][T10889] ? wake_up_klogd.part.0+0x8e/0xd0 [ 688.907764][T10889] ? refcount_warn_saturate+0x1d1/0x1e0 [ 688.913312][T10889] report_bug+0x1bd/0x210 [ 688.917728][T10889] handle_bug+0x38/0x90 [ 688.921890][T10889] exc_invalid_op+0x14/0x40 [ 688.926456][T10889] asm_exc_invalid_op+0x12/0x20 [ 688.931315][T10889] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 688.937487][T10889] Code: e9 db fe ff ff 48 89 df e8 0c 31 f7 fd e9 8a fe ff ff e8 52 5d b6 fd 48 c7 c7 e0 71 d8 88 c6 05 cc 9b 94 07 01 e8 c1 9a 86 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 688.957969][T10889] RSP: 0018:ffffc90008b0fe08 EFLAGS: 00010286 [ 688.964066][T10889] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 688.972039][T10889] RDX: ffff888093202380 RSI: ffffffff815f5985 RDI: fffff52001161fb3 [ 688.980009][T10889] RBP: 0000000000000003 R08: 0000000000000001 R09: ffff8880ae4318e7 [ 688.987979][T10889] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809644d0b8 [ 688.995952][T10889] R13: ffff8880a4239e30 R14: ffff8880a4239e00 R15: ffff8880a79ac800 [ 689.003944][T10889] ? vprintk_func+0x95/0x1d4 [ 689.008542][T10889] ? refcount_warn_saturate+0x1d1/0x1e0 [ 689.014184][T10889] io_wqe_worker+0xcdb/0x10e0 [ 689.018982][T10889] ? lockdep_hardirqs_on_prepare+0x354/0x530 [ 689.024973][T10889] ? io_worker_handle_work+0x13f0/0x13f0 [ 689.030686][T10889] ? lockdep_hardirqs_on+0x53/0x100 [ 689.035953][T10889] ? __kthread_parkme+0x13f/0x1e0 [ 689.040983][T10889] ? io_worker_handle_work+0x13f0/0x13f0 [ 689.046640][T10889] kthread+0x3b5/0x4a0 [ 689.050732][T10889] ? __kthread_bind_mask+0xc0/0xc0 [ 689.055918][T10889] ret_from_fork+0x1f/0x30 [ 689.061615][T10889] Kernel Offset: disabled [ 689.066025][T10889] Rebooting in 86400 seconds..