[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 64.198709][ T27] audit: type=1800 audit(1584359684.786:25): pid=9360 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 64.244094][ T27] audit: type=1800 audit(1584359684.786:26): pid=9360 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 64.301227][ T27] audit: type=1800 audit(1584359684.786:27): pid=9360 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.33' (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 syzkaller login: [ 530.071491][ T3481] ------------[ cut here ]------------ [ 530.079250][ T3481] refcount_t: underflow; use-after-free. [ 530.102954][ T3481] WARNING: CPU: 0 PID: 3481 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 530.112607][ T3481] Kernel panic - not syncing: panic_on_warn set ... executing program executing program executing program executing program executing program [ 530.119212][ T3481] CPU: 0 PID: 3481 Comm: kworker/0:8 Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 [ 530.128767][ T3481] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 530.139089][ T3481] Workqueue: events do_enable_set [ 530.144133][ T3481] Call Trace: [ 530.147640][ T3481] dump_stack+0x188/0x20d [ 530.152004][ T3481] ? refcount_warn_saturate+0x150/0x1e0 [ 530.157912][ T3481] panic+0x2e3/0x75c [ 530.161844][ T3481] ? add_taint.cold+0x16/0x16 [ 530.166908][ T3481] ? __probe_kernel_read+0x188/0x1d0 [ 530.172222][ T3481] ? __warn.cold+0x14/0x35 [ 530.176899][ T3481] ? __warn+0xd5/0x1c8 [ 530.181007][ T3481] ? refcount_warn_saturate+0x1d1/0x1e0 [ 530.187135][ T3481] __warn.cold+0x2f/0x35 [ 530.191415][ T3481] ? refcount_warn_saturate+0x1d1/0x1e0 [ 530.196991][ T3481] report_bug+0x27b/0x2f0 [ 530.201421][ T3481] do_error_trap+0x12b/0x220 [ 530.206044][ T3481] ? refcount_warn_saturate+0x1d1/0x1e0 [ 530.211856][ T3481] do_invalid_op+0x32/0x40 [ 530.216298][ T3481] ? refcount_warn_saturate+0x1d1/0x1e0 [ 530.222179][ T3481] invalid_op+0x23/0x30 [ 530.226364][ T3481] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 530.232535][ T3481] Code: e9 db fe ff ff 48 89 df e8 1c e7 1f fe e9 8a fe ff ff e8 12 c6 e2 fd 48 c7 c7 40 db 71 88 c6 05 b6 a9 f1 06 01 e8 77 91 b4 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 530.252492][ T3481] RSP: 0018:ffffc9000af47c08 EFLAGS: 00010286 [ 530.258791][ T3481] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 530.267044][ T3481] RDX: 0000000000000000 RSI: ffffffff815c4e91 RDI: fffff520015e8f73 [ 530.275036][ T3481] RBP: 0000000000000003 R08: ffff88809bec0600 R09: ffffed1015cc6661 [ 530.283971][ T3481] R10: ffffed1015cc6660 R11: ffff8880ae633307 R12: ffff8880a28ea018 [ 530.292072][ T3481] R13: ffff8880a4c2b700 R14: ffff88809c069300 R15: ffff8880ae636d80 [ 530.300632][ T3481] ? vprintk_func+0x81/0x17e [ 530.305261][ T3481] ? refcount_warn_saturate+0x1d1/0x1e0 [ 530.311026][ T3481] l2cap_chan_put+0x1d3/0x230 [ 530.316358][ T3481] do_enable_set+0x4db/0x8e0 [ 530.321271][ T3481] ? lowpan_control_write+0x480/0x480 [ 530.326915][ T3481] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 530.332518][ T3481] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 530.339294][ T3481] process_one_work+0x94b/0x1690 [ 530.344531][ T3481] ? pwq_dec_nr_in_flight+0x310/0x310 [ 530.350197][ T3481] ? do_raw_spin_lock+0x129/0x2e0 [ 530.355270][ T3481] worker_thread+0x96/0xe20 [ 530.360129][ T3481] ? process_one_work+0x1690/0x1690 [ 530.365356][ T3481] kthread+0x357/0x430 [ 530.369456][ T3481] ? kthread_mod_delayed_work+0x1a0/0x1a0 [ 530.375344][ T3481] ret_from_fork+0x24/0x30 [ 530.381792][ T3481] Kernel Offset: disabled [ 530.386333][ T3481] Rebooting in 86400 seconds..