[ 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. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.41' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 102.837339] IPVS: ftp: loaded support on port[0] = 21 [ 104.866781] Bluetooth: hci0: command 0x0409 tx timeout [ 106.946367] Bluetooth: hci0: command 0x041b tx timeout executing program [ 109.026391] Bluetooth: hci0: command 0x040f tx timeout [ 111.106369] Bluetooth: hci0: command 0x0419 tx timeout executing program [ 113.186367] Bluetooth: hci0: command 0x0405 tx timeout executing program executing program executing program executing program executing program executing program [ 142.947028] ================================================================== [ 142.954632] BUG: KASAN: use-after-free in __lock_acquire+0x2cb4/0x3ff0 [ 142.961284] Read of size 8 at addr ffff8880950baf20 by task kworker/1:1/25 [ 142.968383] [ 142.970608] CPU: 1 PID: 25 Comm: kworker/1:1 Not tainted 4.19.172-syzkaller #0 [ 142.978652] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 142.988203] Workqueue: events l2cap_chan_timeout [ 142.992948] Call Trace: [ 142.995632] dump_stack+0x1fc/0x2ef [ 142.999252] print_address_description.cold+0x54/0x219 [ 143.004600] kasan_report_error.cold+0x8a/0x1b9 [ 143.009335] ? __lock_acquire+0x2cb4/0x3ff0 [ 143.013639] __asan_report_load8_noabort+0x88/0x90 [ 143.018572] ? __lock_acquire+0x2cb4/0x3ff0 [ 143.022891] __lock_acquire+0x2cb4/0x3ff0 [ 143.027037] ? trace_hardirqs_off+0x64/0x200 [ 143.031682] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 143.036804] ? debug_object_assert_init+0x242/0x2e0 [ 143.041811] ? mark_held_locks+0xf0/0xf0 [ 143.045980] ? debug_object_free+0x380/0x380 [ 143.050774] ? mark_held_locks+0xf0/0xf0 [ 143.055602] ? __save_stack_trace+0x9f/0x190 [ 143.059994] ? del_timer+0xc3/0x100 [ 143.063623] lock_acquire+0x170/0x3c0 [ 143.067437] ? lock_sock_nested+0x3b/0x110 [ 143.073139] _raw_spin_lock_bh+0x2f/0x40 [ 143.077187] ? lock_sock_nested+0x3b/0x110 [ 143.081759] lock_sock_nested+0x3b/0x110 [ 143.086244] l2cap_sock_teardown_cb+0xa0/0x6d0 [ 143.090815] ? lock_downgrade+0x720/0x720 [ 143.094947] l2cap_chan_del+0xbc/0xa50 [ 143.098839] ? trace_hardirqs_off+0x64/0x200 [ 143.103230] l2cap_chan_close+0x1b5/0x950 [ 143.107370] ? __set_monitor_timer+0x200/0x200 [ 143.111934] ? check_preemption_disabled+0x41/0x280 [ 143.116942] l2cap_chan_timeout+0x17e/0x2f0 [ 143.121243] process_one_work+0x864/0x1570 [ 143.125470] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 143.130156] worker_thread+0x64c/0x1130 [ 143.134243] ? __kthread_parkme+0x133/0x1e0 [ 143.138556] ? process_one_work+0x1570/0x1570 [ 143.143042] kthread+0x33f/0x460 [ 143.146478] ? kthread_park+0x180/0x180 [ 143.150447] ret_from_fork+0x24/0x30 [ 143.154312] [ 143.155933] Allocated by task 8135: [ 143.159588] __kmalloc+0x15a/0x3c0 [ 143.163167] sk_prot_alloc+0x1e2/0x2d0 [ 143.167058] sk_alloc+0x36/0xec0 [ 143.170422] l2cap_sock_alloc.constprop.0+0x31/0x210 [ 143.175507] l2cap_sock_create+0x123/0x1f0 [ 143.179763] bt_sock_create+0x154/0x2a0 [ 143.183716] __sock_create+0x3d8/0x740 [ 143.187765] __sys_socket+0xef/0x200 [ 143.191509] __x64_sys_socket+0x6f/0xb0 [ 143.195467] do_syscall_64+0xf9/0x620 [ 143.199252] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 143.204416] [ 143.206030] Freed by task 8135: [ 143.209308] kfree+0xcc/0x210 [ 143.212399] __sk_destruct+0x684/0x8a0 [ 143.216264] __sk_free+0x165/0x3b0 [ 143.219789] sk_free+0x3b/0x50 [ 143.222963] l2cap_sock_kill.part.0+0x124/0x150 [ 143.228399] l2cap_sock_release+0x1e6/0x290 [ 143.232710] __sock_release+0xcd/0x2a0 [ 143.236586] sock_close+0x15/0x20 [ 143.241695] __fput+0x2ce/0x890 [ 143.244959] task_work_run+0x148/0x1c0 [ 143.248827] do_exit+0xbf3/0x2be0 [ 143.252265] do_group_exit+0x125/0x310 [ 143.256755] get_signal+0x3f2/0x1f70 [ 143.260450] do_signal+0x8f/0x1670 [ 143.263985] exit_to_usermode_loop+0x204/0x2a0 [ 143.268550] do_syscall_64+0x538/0x620 [ 143.272420] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 143.277593] [ 143.279219] The buggy address belongs to the object at ffff8880950bae80 [ 143.279219] which belongs to the cache kmalloc-2048 of size 2048 [ 143.292240] The buggy address is located 160 bytes inside of [ 143.292240] 2048-byte region [ffff8880950bae80, ffff8880950bb680) [ 143.304285] The buggy address belongs to the page: [ 143.309621] page:ffffea0002542e80 count:1 mapcount:0 mapping:ffff88813bff0c40 index:0x0 compound_mapcount: 0 [ 143.319567] flags: 0xfff00000008100(slab|head) [ 143.324150] raw: 00fff00000008100 ffffea0002c1b608 ffffea0002550f88 ffff88813bff0c40 [ 143.332018] raw: 0000000000000000 ffff8880950ba600 0000000100000003 0000000000000000 [ 143.340159] page dumped because: kasan: bad access detected [ 143.345874] [ 143.347548] Memory state around the buggy address: [ 143.352465] ffff8880950bae00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 143.359899] ffff8880950bae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 143.367385] >ffff8880950baf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 143.374934] ^ [ 143.379424] ffff8880950baf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 143.386787] ffff8880950bb000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 143.394124] ================================================================== [ 143.401462] Disabling lock debugging due to kernel taint [ 143.406914] Kernel panic - not syncing: panic_on_warn set ... [ 143.406914] [ 143.414269] CPU: 1 PID: 25 Comm: kworker/1:1 Tainted: G B 4.19.172-syzkaller #0 [ 143.423001] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 143.432810] Workqueue: events l2cap_chan_timeout [ 143.437545] Call Trace: [ 143.440133] dump_stack+0x1fc/0x2ef [ 143.443744] panic+0x26a/0x50e [ 143.447421] ? __warn_printk+0xf3/0xf3 [ 143.451612] ? lock_downgrade+0x720/0x720 [ 143.455753] ? print_shadow_for_address+0xb8/0x114 [ 143.460679] ? trace_hardirqs_off+0x64/0x200 [ 143.465067] kasan_end_report+0x43/0x49 [ 143.469035] kasan_report_error.cold+0xa7/0x1b9 [ 143.473687] ? __lock_acquire+0x2cb4/0x3ff0 [ 143.477994] __asan_report_load8_noabort+0x88/0x90 [ 143.483017] ? __lock_acquire+0x2cb4/0x3ff0 [ 143.487416] __lock_acquire+0x2cb4/0x3ff0 [ 143.492598] ? trace_hardirqs_off+0x64/0x200 [ 143.496986] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 143.502070] ? debug_object_assert_init+0x242/0x2e0 [ 143.507070] ? mark_held_locks+0xf0/0xf0 [ 143.511107] ? debug_object_free+0x380/0x380 [ 143.516024] ? mark_held_locks+0xf0/0xf0 [ 143.520074] ? __save_stack_trace+0x9f/0x190 [ 143.524472] ? del_timer+0xc3/0x100 [ 143.528094] lock_acquire+0x170/0x3c0 [ 143.532146] ? lock_sock_nested+0x3b/0x110 [ 143.536419] _raw_spin_lock_bh+0x2f/0x40 [ 143.540495] ? lock_sock_nested+0x3b/0x110 [ 143.544722] lock_sock_nested+0x3b/0x110 [ 143.548975] l2cap_sock_teardown_cb+0xa0/0x6d0 [ 143.553631] ? lock_downgrade+0x720/0x720 [ 143.557791] l2cap_chan_del+0xbc/0xa50 [ 143.561705] ? trace_hardirqs_off+0x64/0x200 [ 143.566110] l2cap_chan_close+0x1b5/0x950 [ 143.570354] ? __set_monitor_timer+0x200/0x200 [ 143.574929] ? check_preemption_disabled+0x41/0x280 [ 143.579950] l2cap_chan_timeout+0x17e/0x2f0 [ 143.584260] process_one_work+0x864/0x1570 [ 143.588489] ? pwq_dec_nr_in_flight+0x2d0/0x2d0 [ 143.593161] worker_thread+0x64c/0x1130 [ 143.597120] ? __kthread_parkme+0x133/0x1e0 [ 143.601531] ? process_one_work+0x1570/0x1570 [ 143.606220] kthread+0x33f/0x460 [ 143.609569] ? kthread_park+0x180/0x180 [ 143.613524] ret_from_fork+0x24/0x30 [ 143.617841] Kernel Offset: disabled [ 143.621546] Rebooting in 86400 seconds..