[ 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 '10.128.1.35' (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 syzkaller login: [ 561.223682][ T2980] ================================================================== [ 561.232185][ T2980] BUG: KASAN: use-after-free in l2cap_chan_close+0x564/0xb10 [ 561.239572][ T2980] Read of size 1 at addr ffff88809678c020 by task kworker/1:123/2980 [ 561.247648][ T2980] [ 561.249994][ T2980] CPU: 1 PID: 2980 Comm: kworker/1:123 Not tainted 5.8.0-syzkaller #0 [ 561.258164][ T2980] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 561.268316][ T2980] Workqueue: events do_enable_set executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 561.273421][ T2980] Call Trace: [ 561.276851][ T2980] dump_stack+0x18f/0x20d [ 561.281216][ T2980] ? l2cap_chan_close+0x564/0xb10 [ 561.286265][ T2980] ? l2cap_chan_close+0x564/0xb10 [ 561.291457][ T2980] print_address_description.constprop.0.cold+0xae/0x436 [ 561.298562][ T2980] ? lockdep_hardirqs_off+0x66/0xa0 [ 561.303899][ T2980] ? vprintk_func+0x97/0x1a6 [ 561.308535][ T2980] ? l2cap_chan_close+0x564/0xb10 [ 561.313584][ T2980] kasan_report.cold+0x1f/0x37 [ 561.318378][ T2980] ? l2cap_chan_close+0x564/0xb10 [ 561.323441][ T2980] l2cap_chan_close+0x564/0xb10 [ 561.328314][ T2980] ? l2cap_retransmit_all+0x760/0x760 [ 561.333776][ T2980] ? lockdep_hardirqs_on_prepare+0x590/0x590 [ 561.339758][ T2980] do_enable_set+0x4ed/0x980 [ 561.344339][ T2980] ? chan_recv_cb+0xa10/0xa10 [ 561.349045][ T2980] ? _raw_spin_unlock_irq+0x1f/0x80 [ 561.354237][ T2980] ? _raw_spin_unlock_irq+0x1f/0x80 [ 561.359428][ T2980] ? lock_is_held_type+0xb0/0xe0 [ 561.364453][ T2980] process_one_work+0x94c/0x1670 [ 561.369397][ T2980] ? lock_release+0x8d0/0x8d0 [ 561.374067][ T2980] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 561.379451][ T2980] ? rwlock_bug.part.0+0x90/0x90 [ 561.384383][ T2980] ? lockdep_hardirqs_off+0x66/0xa0 [ 561.389578][ T2980] worker_thread+0x64c/0x1120 [ 561.394252][ T2980] ? process_one_work+0x1670/0x1670 [ 561.399445][ T2980] kthread+0x3b5/0x4a0 [ 561.403509][ T2980] ? __kthread_bind_mask+0xc0/0xc0 [ 561.408609][ T2980] ? __kthread_bind_mask+0xc0/0xc0 [ 561.413819][ T2980] ret_from_fork+0x1f/0x30 [ 561.418228][ T2980] [ 561.420594][ T2980] Allocated by task 2980: [ 561.424923][ T2980] save_stack+0x1b/0x40 [ 561.429067][ T2980] __kasan_kmalloc.constprop.0+0xc2/0xd0 [ 561.434696][ T2980] kmem_cache_alloc_trace+0x14f/0x2d0 [ 561.440061][ T2980] l2cap_chan_create+0x40/0x3a0 [ 561.445105][ T2980] do_enable_set+0x52f/0x980 [ 561.449709][ T2980] process_one_work+0x94c/0x1670 [ 561.454639][ T2980] worker_thread+0x64c/0x1120 [ 561.460255][ T2980] kthread+0x3b5/0x4a0 [ 561.464309][ T2980] ret_from_fork+0x1f/0x30 [ 561.469161][ T2980] [ 561.471476][ T2980] Freed by task 6977: [ 561.475535][ T2980] save_stack+0x1b/0x40 [ 561.479676][ T2980] __kasan_slab_free+0xf5/0x140 [ 561.484601][ T2980] kfree+0x103/0x2c0 [ 561.488509][ T2980] l2cap_chan_put+0x1b2/0x230 [ 561.493174][ T2980] do_enable_set+0x4f9/0x980 [ 561.497948][ T2980] process_one_work+0x94c/0x1670 [ 561.502892][ T2980] worker_thread+0x64c/0x1120 [ 561.507557][ T2980] kthread+0x3b5/0x4a0 [ 561.511616][ T2980] ret_from_fork+0x1f/0x30 [ 561.516011][ T2980] [ 561.518334][ T2980] The buggy address belongs to the object at ffff88809678c000 [ 561.518334][ T2980] which belongs to the cache kmalloc-2k of size 2048 [ 561.533785][ T2980] The buggy address is located 32 bytes inside of [ 561.533785][ T2980] 2048-byte region [ffff88809678c000, ffff88809678c800) [ 561.548525][ T2980] The buggy address belongs to the page: [ 561.554150][ T2980] page:ffffea000259e300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 [ 561.563509][ T2980] flags: 0xfffe0000000200(slab) [ 561.568354][ T2980] raw: 00fffe0000000200 ffffea0002538d08 ffffea00027c8848 ffff8880aa000e00 [ 561.577018][ T2980] raw: 0000000000000000 ffff88809678c000 0000000100000001 0000000000000000 [ 561.585607][ T2980] page dumped because: kasan: bad access detected [ 561.592026][ T2980] [ 561.594337][ T2980] Memory state around the buggy address: [ 561.600997][ T2980] ffff88809678bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 561.610450][ T2980] ffff88809678bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 561.618718][ T2980] >ffff88809678c000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 561.626789][ T2980] ^ [ 561.632144][ T2980] ffff88809678c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 561.640210][ T2980] ffff88809678c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 561.648268][ T2980] ================================================================== [ 561.656316][ T2980] 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 [ 561.741062][ T2980] Kernel panic - not syncing: panic_on_warn set ... [ 561.748137][ T2980] CPU: 1 PID: 2980 Comm: kworker/1:123 Tainted: G B 5.8.0-syzkaller #0 [ 561.757682][ T2980] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 561.767760][ T2980] Workqueue: events do_enable_set [ 561.772784][ T2980] Call Trace: [ 561.776189][ T2980] dump_stack+0x18f/0x20d [ 561.780534][ T2980] ? l2cap_chan_close+0x520/0xb10 [ 561.785648][ T2980] panic+0x2e3/0x75c executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 561.789564][ T2980] ? __warn_printk+0xf3/0xf3 [ 561.794185][ T2980] ? preempt_schedule_common+0x59/0xc0 [ 561.799660][ T2980] ? l2cap_chan_close+0x564/0xb10 [ 561.804702][ T2980] ? preempt_schedule_thunk+0x16/0x18 [ 561.810178][ T2980] ? trace_hardirqs_on+0x55/0x220 [ 561.815222][ T2980] ? l2cap_chan_close+0x564/0xb10 [ 561.820444][ T2980] ? l2cap_chan_close+0x564/0xb10 [ 561.825490][ T2980] end_report+0x4d/0x53 [ 561.829657][ T2980] kasan_report.cold+0xd/0x37 [ 561.834346][ T2980] ? l2cap_chan_close+0x564/0xb10 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 561.839380][ T2980] l2cap_chan_close+0x564/0xb10 [ 561.844258][ T2980] ? l2cap_retransmit_all+0x760/0x760 [ 561.849654][ T2980] ? lockdep_hardirqs_on_prepare+0x590/0x590 [ 561.855654][ T2980] do_enable_set+0x4ed/0x980 [ 561.860277][ T2980] ? chan_recv_cb+0xa10/0xa10 [ 561.864977][ T2980] ? _raw_spin_unlock_irq+0x1f/0x80 [ 561.870278][ T2980] ? _raw_spin_unlock_irq+0x1f/0x80 [ 561.875587][ T2980] ? lock_is_held_type+0xb0/0xe0 [ 561.880545][ T2980] process_one_work+0x94c/0x1670 [ 561.885506][ T2980] ? lock_release+0x8d0/0x8d0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 561.890220][ T2980] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 561.895614][ T2980] ? rwlock_bug.part.0+0x90/0x90 [ 561.900568][ T2980] ? lockdep_hardirqs_off+0x66/0xa0 [ 561.905779][ T2980] worker_thread+0x64c/0x1120 [ 561.910475][ T2980] ? process_one_work+0x1670/0x1670 [ 561.915684][ T2980] kthread+0x3b5/0x4a0 [ 561.919766][ T2980] ? __kthread_bind_mask+0xc0/0xc0 [ 561.924890][ T2980] ? __kthread_bind_mask+0xc0/0xc0 [ 561.930012][ T2980] ret_from_fork+0x1f/0x30 [ 561.935814][ T2980] Kernel Offset: disabled [ 561.940139][ T2980] Rebooting in 86400 seconds..