[ 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 '10.128.10.12' (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 syzkaller login: [ 60.992333][ T2787] ================================================================== [ 61.000593][ T2787] BUG: KASAN: use-after-free in l2cap_chan_close+0x763/0xb10 [ 61.007976][ T2787] Read of size 1 at addr ffff8880a0113020 by task kworker/0:4/2787 [ 61.015858][ T2787] [ 61.018193][ T2787] CPU: 0 PID: 2787 Comm: kworker/0:4 Not tainted 5.7.0-rc4-syzkaller #0 [ 61.026512][ T2787] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.036600][ T2787] Workqueue: events do_enable_set executing program executing program executing program [ 61.041622][ T2787] Call Trace: [ 61.044913][ T2787] dump_stack+0x188/0x20d [ 61.049252][ T2787] print_address_description.constprop.0.cold+0xd3/0x315 [ 61.056274][ T2787] ? l2cap_chan_close+0x763/0xb10 [ 61.061323][ T2787] __kasan_report.cold+0x35/0x4d [ 61.066266][ T2787] ? l2cap_chan_close+0x763/0xb10 [ 61.071295][ T2787] ? l2cap_chan_close+0x763/0xb10 [ 61.076316][ T2787] kasan_report+0x33/0x50 [ 61.080647][ T2787] l2cap_chan_close+0x763/0xb10 [ 61.085502][ T2787] ? l2cap_send_i_or_rr_or_rnr+0x320/0x320 executing program executing program [ 61.091326][ T2787] do_enable_set+0x4cf/0x8e0 [ 61.095957][ T2787] ? lowpan_control_write+0x480/0x480 [ 61.101330][ T2787] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 61.106883][ T2787] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 61.112863][ T2787] ? _raw_spin_unlock_irq+0x1f/0x80 [ 61.118069][ T2787] process_one_work+0x965/0x16a0 [ 61.123022][ T2787] ? lock_release+0x800/0x800 [ 61.127700][ T2787] ? pwq_dec_nr_in_flight+0x310/0x310 [ 61.133076][ T2787] ? rwlock_bug.part.0+0x90/0x90 [ 61.138052][ T2787] worker_thread+0x96/0xe20 executing program executing program executing program [ 61.142565][ T2787] ? process_one_work+0x16a0/0x16a0 [ 61.147766][ T2787] kthread+0x388/0x470 [ 61.151832][ T2787] ? kthread_mod_delayed_work+0x1a0/0x1a0 [ 61.157554][ T2787] ret_from_fork+0x24/0x30 [ 61.161981][ T2787] [ 61.164308][ T2787] Allocated by task 3872: [ 61.168635][ T2787] save_stack+0x1b/0x40 [ 61.172790][ T2787] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 61.178421][ T2787] kmem_cache_alloc_trace+0x153/0x7d0 [ 61.183788][ T2787] l2cap_chan_create+0x40/0x3a0 [ 61.188744][ T2787] chan_create+0xc/0xd0 executing program executing program executing program [ 61.192898][ T2787] do_enable_set+0x511/0x8e0 [ 61.197510][ T2787] process_one_work+0x965/0x16a0 [ 61.202448][ T2787] worker_thread+0x96/0xe20 [ 61.206948][ T2787] kthread+0x388/0x470 [ 61.211020][ T2787] ret_from_fork+0x24/0x30 [ 61.215449][ T2787] [ 61.217770][ T2787] Freed by task 3872: [ 61.221744][ T2787] save_stack+0x1b/0x40 [ 61.225899][ T2787] __kasan_slab_free+0xf7/0x140 [ 61.230750][ T2787] kfree+0x109/0x2b0 [ 61.234644][ T2787] l2cap_chan_put+0x1b2/0x230 executing program executing program [ 61.239320][ T2787] do_enable_set+0x4db/0x8e0 [ 61.243908][ T2787] process_one_work+0x965/0x16a0 [ 61.248841][ T2787] worker_thread+0x96/0xe20 [ 61.253340][ T2787] kthread+0x388/0x470 [ 61.257406][ T2787] ret_from_fork+0x24/0x30 [ 61.261811][ T2787] [ 61.264137][ T2787] The buggy address belongs to the object at ffff8880a0113000 [ 61.264137][ T2787] which belongs to the cache kmalloc-2k of size 2048 [ 61.278188][ T2787] The buggy address is located 32 bytes inside of [ 61.278188][ T2787] 2048-byte region [ffff8880a0113000, ffff8880a0113800) executing program executing program executing program [ 61.291455][ T2787] The buggy address belongs to the page: [ 61.297091][ T2787] page:ffffea00028044c0 refcount:1 mapcount:0 mapping:00000000dcca57ad index:0x0 [ 61.306201][ T2787] flags: 0xfffe0000000200(slab) [ 61.311061][ T2787] raw: 00fffe0000000200 ffffea0002541408 ffffea00023f3ec8 ffff8880aa000e00 [ 61.319733][ T2787] raw: 0000000000000000 ffff8880a0113000 0000000100000001 0000000000000000 [ 61.328309][ T2787] page dumped because: kasan: bad access detected [ 61.334712][ T2787] [ 61.337035][ T2787] Memory state around the buggy address: executing program executing program [ 61.342666][ T2787] ffff8880a0112f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 61.350732][ T2787] ffff8880a0112f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 61.358794][ T2787] >ffff8880a0113000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 61.366851][ T2787] ^ [ 61.371962][ T2787] ffff8880a0113080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 61.380033][ T2787] ffff8880a0113100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program executing program [ 61.388088][ T2787] ================================================================== [ 61.396148][ T2787] 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 [ 61.564331][ T2787] Kernel panic - not syncing: panic_on_warn set ... [ 61.570970][ T2787] CPU: 0 PID: 2787 Comm: kworker/0:4 Tainted: G B 5.7.0-rc4-syzkaller #0 [ 61.580677][ T2787] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.590757][ T2787] Workqueue: events do_enable_set [ 61.595776][ T2787] Call Trace: [ 61.599089][ T2787] dump_stack+0x188/0x20d [ 61.603415][ T2787] panic+0x2e3/0x75c [ 61.607306][ T2787] ? add_taint.cold+0x16/0x16 executing program executing program executing program [ 61.611979][ T2787] ? preempt_schedule_common+0x5e/0xc0 [ 61.617438][ T2787] ? l2cap_chan_close+0x763/0xb10 [ 61.622460][ T2787] ? preempt_schedule_thunk+0x16/0x18 [ 61.627831][ T2787] ? trace_hardirqs_on+0x55/0x220 [ 61.632851][ T2787] ? l2cap_chan_close+0x763/0xb10 [ 61.637871][ T2787] end_report+0x4d/0x53 [ 61.642042][ T2787] __kasan_report.cold+0xd/0x4d [ 61.646897][ T2787] ? l2cap_chan_close+0x763/0xb10 [ 61.651927][ T2787] ? l2cap_chan_close+0x763/0xb10 [ 61.656949][ T2787] kasan_report+0x33/0x50 executing program executing program executing program [ 61.661272][ T2787] l2cap_chan_close+0x763/0xb10 [ 61.666118][ T2787] ? l2cap_send_i_or_rr_or_rnr+0x320/0x320 [ 61.671935][ T2787] do_enable_set+0x4cf/0x8e0 [ 61.676521][ T2787] ? lowpan_control_write+0x480/0x480 [ 61.681888][ T2787] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 61.687431][ T2787] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 61.693406][ T2787] ? _raw_spin_unlock_irq+0x1f/0x80 [ 61.698600][ T2787] process_one_work+0x965/0x16a0 [ 61.703534][ T2787] ? lock_release+0x800/0x800 [ 61.708206][ T2787] ? pwq_dec_nr_in_flight+0x310/0x310 executing program [ 61.713573][ T2787] ? rwlock_bug.part.0+0x90/0x90 [ 61.718508][ T2787] worker_thread+0x96/0xe20 [ 61.723011][ T2787] ? process_one_work+0x16a0/0x16a0 [ 61.728209][ T2787] kthread+0x388/0x470 [ 61.732271][ T2787] ? kthread_mod_delayed_work+0x1a0/0x1a0 [ 61.738018][ T2787] ret_from_fork+0x24/0x30 [ 61.743496][ T2787] Kernel Offset: disabled [ 61.747806][ T2787] Rebooting in 86400 seconds..