[ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Started Getty on tty6. [ OK ] Started Getty on tty5. [ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.20' (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 syzkaller login: [ 67.441371][ T29] audit: type=1400 audit(1596569991.681:8): avc: denied { execmem } for pid=6829 comm="syz-executor724" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 67.823428][ T28] ------------[ cut here ]------------ [ 67.830373][ T28] refcount_t: underflow; use-after-free. [ 67.852325][ T28] WARNING: CPU: 1 PID: 28 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 67.883965][ T28] Kernel panic - not syncing: panic_on_warn set ... [ 67.890584][ T28] CPU: 1 PID: 28 Comm: kworker/1:1 Not tainted 5.8.0-syzkaller #0 [ 67.898384][ T28] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.908453][ T28] Workqueue: events do_enable_set [ 67.913478][ T28] Call Trace: [ 67.916778][ T28] dump_stack+0x18f/0x20d [ 67.921130][ T28] panic+0x2e3/0x75c [ 67.925039][ T28] ? __warn_printk+0xf3/0xf3 executing program executing program executing program [ 67.929641][ T28] ? refcount_warn_saturate+0x1d1/0x1e0 [ 67.935196][ T28] ? xfs_alloc_fix_freelist+0xe5a/0x1050 [ 67.940835][ T28] ? refcount_warn_saturate+0x1d1/0x1e0 [ 67.946391][ T28] ? __warn.cold+0x5/0x45 [ 67.950754][ T28] ? __warn+0xd6/0x1f2 [ 67.954830][ T28] ? refcount_warn_saturate+0x1d1/0x1e0 [ 67.960382][ T28] __warn.cold+0x20/0x45 [ 67.964635][ T28] ? refcount_warn_saturate+0x1d1/0x1e0 [ 67.970191][ T28] report_bug+0x1bd/0x210 [ 67.974539][ T28] handle_bug+0x38/0x90 [ 67.978708][ T28] ? __warn_printk+0xc6/0xf3 [ 67.983304][ T28] exc_invalid_op+0x14/0x40 [ 67.987817][ T28] asm_exc_invalid_op+0x12/0x20 [ 67.992786][ T28] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 67.998946][ T28] Code: e9 db fe ff ff 48 89 df e8 4c 94 1b fe e9 8a fe ff ff e8 12 1b dc fd 48 c7 c7 60 62 93 88 c6 05 a2 8d 12 07 01 e8 01 40 ad fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 68.018553][ T28] RSP: 0018:ffffc90000e27bd0 EFLAGS: 00010282 [ 68.024635][ T28] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 68.032617][ T28] RDX: ffff8880a90aa140 RSI: ffffffff815d9947 RDI: fffff520001c4f6c [ 68.041028][ T28] RBP: 0000000000000003 R08: 0000000000000001 R09: ffff8880ae731927 [ 68.049014][ T28] R10: 0000000000000000 R11: 0000000000003254 R12: ffff8880926be018 [ 68.057080][ T28] R13: ffff88809ee53a10 R14: ffff8880a97b5600 R15: ffff88809ee53a00 [ 68.065078][ T28] ? vprintk_func+0x97/0x1a6 [ 68.069778][ T28] l2cap_chan_put+0x1d3/0x230 [ 68.074472][ T28] do_enable_set+0x4f9/0x980 [ 68.079082][ T28] ? chan_recv_cb+0xa10/0xa10 [ 68.083769][ T28] ? _raw_spin_unlock_irq+0x1f/0x80 [ 68.088982][ T28] ? _raw_spin_unlock_irq+0x1f/0x80 [ 68.094188][ T28] ? lock_is_held_type+0xbb/0xf0 [ 68.099230][ T28] process_one_work+0x94c/0x1670 [ 68.104227][ T28] ? lock_release+0x8e0/0x8e0 [ 68.108917][ T28] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 68.114305][ T28] ? rwlock_bug.part.0+0x90/0x90 [ 68.119270][ T28] worker_thread+0x64c/0x1120 [ 68.123967][ T28] ? __kthread_parkme+0x13f/0x1e0 [ 68.129017][ T28] ? process_one_work+0x1670/0x1670 [ 68.134229][ T28] kthread+0x3b5/0x4a0 [ 68.138312][ T28] ? __kthread_bind_mask+0xc0/0xc0 [ 68.143437][ T28] ? __kthread_bind_mask+0xc0/0xc0 [ 68.148562][ T28] ret_from_fork+0x1f/0x30 [ 68.154568][ T28] Kernel Offset: disabled [ 68.159002][ T28] Rebooting in 86400 seconds..