[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.57' (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 syzkaller login: [ 36.595171] audit: type=1400 audit(1596872464.231:8): avc: denied { execmem } for pid=6368 comm="syz-executor656" 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 [ 36.675502] ================================================================== [ 36.683023] BUG: KASAN: use-after-free in l2cap_chan_close+0x4fb/0x770 [ 36.689696] Read of size 1 at addr ffff88809b6da960 by task kworker/0:2/2874 [ 36.696871] [ 36.698497] CPU: 0 PID: 2874 Comm: kworker/0:2 Not tainted 4.14.193-syzkaller #0 [ 36.706031] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 36.715388] Workqueue: events do_enable_set [ 36.719705] Call Trace: [ 36.722290] dump_stack+0x1b2/0x283 [ 36.725925] print_address_description.cold+0x54/0x1d3 [ 36.731206] kasan_report_error.cold+0x8a/0x194 [ 36.735884] ? l2cap_chan_close+0x4fb/0x770 [ 36.740204] __asan_report_load1_noabort+0x68/0x70 [ 36.745137] ? l2cap_chan_close+0x4fb/0x770 [ 36.749468] l2cap_chan_close+0x4fb/0x770 [ 36.753612] ? __set_monitor_timer+0x110/0x110 [ 36.758198] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 36.763299] do_enable_set+0x473/0x8a0 [ 36.767190] ? lock_acquire+0x170/0x3f0 [ 36.771167] ? chan_recv_cb+0x970/0x970 [ 36.775140] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 36.780592] process_one_work+0x793/0x14a0 [ 36.784828] ? work_busy+0x320/0x320 [ 36.788533] ? worker_thread+0x158/0xff0 [ 36.792610] ? _raw_spin_unlock_irq+0x24/0x80 [ 36.797106] worker_thread+0x5cc/0xff0 [ 36.801002] ? rescuer_thread+0xc80/0xc80 [ 36.805146] kthread+0x30d/0x420 [ 36.808513] ? kthread_create_on_node+0xd0/0xd0 [ 36.813192] ret_from_fork+0x24/0x30 [ 36.816903] [ 36.818519] Allocated by task 2755: [ 36.822143] kasan_kmalloc+0xeb/0x160 [ 36.825953] kmem_cache_alloc_trace+0x131/0x3d0 [ 36.830616] l2cap_chan_create+0x3e/0x3c0 [ 36.834758] do_enable_set+0x4ac/0x8a0 [ 36.838644] process_one_work+0x793/0x14a0 [ 36.842878] worker_thread+0x5cc/0xff0 [ 36.846764] kthread+0x30d/0x420 [ 36.850124] ret_from_fork+0x24/0x30 [ 36.853826] [ 36.855446] Freed by task 2755: [ 36.858720] kasan_slab_free+0xc3/0x1a0 [ 36.862686] kfree+0xc9/0x250 [ 36.865783] l2cap_chan_put+0x152/0x1b0 [ 36.869748] do_enable_set+0x47f/0x8a0 [ 36.873629] process_one_work+0x793/0x14a0 [ 36.877854] worker_thread+0x5cc/0xff0 [ 36.881734] kthread+0x30d/0x420 [ 36.885093] ret_from_fork+0x24/0x30 [ 36.888795] [ 36.890412] The buggy address belongs to the object at ffff88809b6da940 [ 36.890412] which belongs to the cache kmalloc-2048 of size 2048 [ 36.903239] The buggy address is located 32 bytes inside of [ 36.903239] 2048-byte region [ffff88809b6da940, ffff88809b6db140) [ 36.915108] The buggy address belongs to the page: [ 36.920037] page:ffffea00026db680 count:1 mapcount:0 mapping:ffff88809b6da0c0 index:0x0 compound_mapcount: 0 [ 36.930004] flags: 0xfffe0000008100(slab|head) [ 36.934584] raw: 00fffe0000008100 ffff88809b6da0c0 0000000000000000 0000000100000003 [ 36.942461] raw: ffffea00025c2620 ffffea00025ca4a0 ffff88812fe52c40 0000000000000000 [ 36.950331] page dumped because: kasan: bad access detected [ 36.956030] [ 36.957649] Memory state around the buggy address: [ 36.962569] ffff88809b6da800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 36.969919] ffff88809b6da880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 36.977269] >ffff88809b6da900: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 36.984619] ^ [ 36.991105] ffff88809b6da980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.998467] ffff88809b6daa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 37.005817] ================================================================== [ 37.013167] Disabling lock debugging due to kernel taint executing program executing program executing program executing program executing program [ 37.064177] Kernel panic - not syncing: panic_on_warn set ... [ 37.064177] [ 37.071564] CPU: 0 PID: 2874 Comm: kworker/0:2 Tainted: G B 4.14.193-syzkaller #0 [ 37.080300] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 37.089649] Workqueue: events do_enable_set [ 37.093961] Call Trace: [ 37.096540] dump_stack+0x1b2/0x283 [ 37.100162] panic+0x1f9/0x42d [ 37.103345] ? add_taint.cold+0x16/0x16 [ 37.107311] ? ___preempt_schedule+0x16/0x18 [ 37.111713] kasan_end_report+0x43/0x49 [ 37.115681] kasan_report_error.cold+0xa7/0x194 [ 37.120343] ? l2cap_chan_close+0x4fb/0x770 [ 37.124659] __asan_report_load1_noabort+0x68/0x70 [ 37.129583] ? l2cap_chan_close+0x4fb/0x770 [ 37.133898] l2cap_chan_close+0x4fb/0x770 [ 37.138046] ? __set_monitor_timer+0x110/0x110 [ 37.142622] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 37.147719] do_enable_set+0x473/0x8a0 [ 37.151606] ? lock_acquire+0x170/0x3f0 [ 37.155572] ? chan_recv_cb+0x970/0x970 [ 37.159538] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 37.164981] process_one_work+0x793/0x14a0 [ 37.169213] ? work_busy+0x320/0x320 [ 37.172913] ? worker_thread+0x158/0xff0 [ 37.176965] ? _raw_spin_unlock_irq+0x24/0x80 [ 37.181452] worker_thread+0x5cc/0xff0 [ 37.185338] ? rescuer_thread+0xc80/0xc80 [ 37.189559] kthread+0x30d/0x420 [ 37.192912] ? kthread_create_on_node+0xd0/0xd0 [ 37.197574] ret_from_fork+0x24/0x30 [ 37.202425] Kernel Offset: disabled [ 37.206033] Rebooting in 86400 seconds..