[ 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... [ 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 '10.128.0.170' (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 syzkaller login: [ 44.513482][ T2597] ================================================================== [ 44.521767][ T2597] BUG: KASAN: use-after-free in l2cap_chan_close+0x46/0xae0 [ 44.529083][ T2597] Read of size 8 at addr ffff888096e33000 by task kworker/0:2/2597 [ 44.536954][ T2597] [ 44.539289][ T2597] CPU: 0 PID: 2597 Comm: kworker/0:2 Not tainted 5.8.0-syzkaller #0 [ 44.547248][ T2597] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.557315][ T2597] Workqueue: events do_enable_set [ 44.562328][ T2597] Call Trace: [ 44.565616][ T2597] dump_stack+0x1f0/0x31e [ 44.569950][ T2597] print_address_description+0x66/0x5a0 [ 44.575526][ T2597] ? vprintk_emit+0x342/0x3c0 [ 44.580202][ T2597] ? printk+0x62/0x83 [ 44.584168][ T2597] ? vprintk_emit+0x339/0x3c0 [ 44.588856][ T2597] kasan_report+0x132/0x1d0 [ 44.593367][ T2597] ? l2cap_chan_close+0x46/0xae0 [ 44.598305][ T2597] ? lock_acquire+0x160/0x730 [ 44.602979][ T2597] l2cap_chan_close+0x46/0xae0 [ 44.607747][ T2597] do_enable_set+0x662/0x900 [ 44.612335][ T2597] ? lock_is_held_type+0xb3/0xe0 [ 44.617282][ T2597] process_one_work+0x789/0xfc0 [ 44.622149][ T2597] worker_thread+0xaa4/0x1460 [ 44.626831][ T2597] ? _raw_spin_unlock_irqrestore+0x6f/0xd0 [ 44.632647][ T2597] kthread+0x37e/0x3a0 [ 44.636713][ T2597] ? rcu_lock_release+0x20/0x20 [ 44.641553][ T2597] ? kthread_blkcg+0xd0/0xd0 [ 44.646140][ T2597] ret_from_fork+0x1f/0x30 [ 44.650552][ T2597] [ 44.652870][ T2597] Allocated by task 2597: [ 44.657219][ T2597] __kasan_kmalloc+0x103/0x140 [ 44.661986][ T2597] kmem_cache_alloc_trace+0x234/0x300 [ 44.667346][ T2597] l2cap_chan_create+0x4c/0x320 [ 44.672187][ T2597] do_enable_set+0x6a7/0x900 [ 44.676768][ T2597] process_one_work+0x789/0xfc0 [ 44.681615][ T2597] worker_thread+0xaa4/0x1460 [ 44.686293][ T2597] kthread+0x37e/0x3a0 [ 44.690363][ T2597] ret_from_fork+0x1f/0x30 [ 44.694937][ T2597] [ 44.697261][ T2597] Freed by task 2576: [ 44.701247][ T2597] __kasan_slab_free+0x114/0x170 [ 44.706181][ T2597] kfree+0x10a/0x220 [ 44.710093][ T2597] do_enable_set+0x66e/0x900 [ 44.714680][ T2597] process_one_work+0x789/0xfc0 [ 44.719531][ T2597] worker_thread+0xaa4/0x1460 [ 44.724228][ T2597] kthread+0x37e/0x3a0 [ 44.728298][ T2597] ret_from_fork+0x1f/0x30 [ 44.732711][ T2597] [ 44.735040][ T2597] The buggy address belongs to the object at ffff888096e33000 [ 44.735040][ T2597] which belongs to the cache kmalloc-2k of size 2048 [ 44.749091][ T2597] The buggy address is located 0 bytes inside of [ 44.749091][ T2597] 2048-byte region [ffff888096e33000, ffff888096e33800) [ 44.762274][ T2597] The buggy address belongs to the page: [ 44.767916][ T2597] page:ffffea00025b8cc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 [ 44.777021][ T2597] flags: 0xfffe0000000200(slab) [ 44.781875][ T2597] raw: 00fffe0000000200 ffffea0002858c88 ffffea00028b3588 ffff8880aa400e00 [ 44.790489][ T2597] raw: 0000000000000000 ffff888096e33000 0000000100000001 0000000000000000 [ 44.799069][ T2597] page dumped because: kasan: bad access detected [ 44.805474][ T2597] [ 44.807790][ T2597] Memory state around the buggy address: [ 44.813415][ T2597] ffff888096e32f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 44.821479][ T2597] ffff888096e32f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 44.829541][ T2597] >ffff888096e33000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 44.837593][ T2597] ^ [ 44.841648][ T2597] ffff888096e33080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 44.849722][ T2597] ffff888096e33100: 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 [ 44.857771][ T2597] ================================================================== [ 44.865822][ T2597] Disabling lock debugging due to kernel taint executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 44.975700][ T2597] Kernel panic - not syncing: panic_on_warn set ... [ 44.982352][ T2597] CPU: 0 PID: 2597 Comm: kworker/0:2 Tainted: G B 5.8.0-syzkaller #0 [ 44.991698][ T2597] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.001797][ T2597] Workqueue: events do_enable_set [ 45.006798][ T2597] Call Trace: [ 45.010084][ T2597] dump_stack+0x1f0/0x31e [ 45.014406][ T2597] panic+0x264/0x7a0 [ 45.018296][ T2597] ? trace_hardirqs_on+0x30/0x80 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 45.023236][ T2597] kasan_report+0x1c9/0x1d0 [ 45.027744][ T2597] ? l2cap_chan_close+0x46/0xae0 [ 45.032681][ T2597] ? lock_acquire+0x160/0x730 [ 45.037357][ T2597] l2cap_chan_close+0x46/0xae0 [ 45.042126][ T2597] do_enable_set+0x662/0x900 [ 45.047329][ T2597] ? lock_is_held_type+0xb3/0xe0 [ 45.052288][ T2597] process_one_work+0x789/0xfc0 [ 45.057146][ T2597] worker_thread+0xaa4/0x1460 [ 45.061829][ T2597] ? _raw_spin_unlock_irqrestore+0x6f/0xd0 [ 45.067720][ T2597] kthread+0x37e/0x3a0 executing program executing program executing program [ 45.071785][ T2597] ? rcu_lock_release+0x20/0x20 [ 45.076629][ T2597] ? kthread_blkcg+0xd0/0xd0 [ 45.081215][ T2597] ret_from_fork+0x1f/0x30 [ 45.086685][ T2597] Kernel Offset: disabled [ 45.090995][ T2597] Rebooting in 86400 seconds..