[ OK ] Started OpenBSD Secure Shell server. [ 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 '10.128.1.46' (ECDSA) to the list of known hosts. syzkaller login: [ 40.743612] audit: type=1400 audit(1601306915.323:8): avc: denied { execmem } for pid=6384 comm="syz-executor465" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1 [ 41.830471] IPVS: ftp: loaded support on port[0] = 21 executing program [ 41.889466] ================================================================== [ 41.896928] BUG: KASAN: use-after-free in hci_chan_del+0x131/0x180 [ 41.903226] Read of size 8 at addr ffff8880926c63d8 by task syz-executor465/6385 [ 41.910833] [ 41.912443] CPU: 0 PID: 6385 Comm: syz-executor465 Not tainted 4.14.198-syzkaller #0 [ 41.920298] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.929628] Call Trace: [ 41.932212] dump_stack+0x1b2/0x283 [ 41.935820] ? l2cap_conn_del+0x670/0x670 [ 41.940047] print_address_description.cold+0x54/0x1d3 [ 41.945303] kasan_report_error.cold+0x8a/0x194 [ 41.949947] ? hci_chan_del+0x131/0x180 [ 41.953898] __asan_report_load8_noabort+0x68/0x70 [ 41.958808] ? hci_chan_del+0x131/0x180 [ 41.962846] hci_chan_del+0x131/0x180 [ 41.966648] l2cap_conn_del+0x417/0x670 [ 41.970600] ? __mutex_unlock_slowpath+0x75/0x770 [ 41.975422] ? l2cap_conn_del+0x670/0x670 [ 41.979544] l2cap_disconn_cfm+0x6b/0x80 [ 41.983597] hci_conn_hash_flush+0x114/0x220 [ 41.987986] hci_dev_do_close+0x542/0xc50 [ 41.992126] ? lock_downgrade+0x740/0x740 [ 41.996341] hci_unregister_dev+0x170/0x7a0 [ 42.000653] ? fcntl_setlk+0xdb0/0xdb0 [ 42.004520] ? vhci_close_dev+0x50/0x50 [ 42.008470] vhci_release+0x70/0xe0 [ 42.012076] __fput+0x25f/0x7a0 [ 42.015336] task_work_run+0x11f/0x190 [ 42.019205] do_exit+0xa08/0x27f0 [ 42.022640] ? mm_update_next_owner+0x5b0/0x5b0 [ 42.027284] ? vfs_write+0x319/0x4d0 [ 42.030989] ? SyS_write+0x14d/0x210 [ 42.034680] do_group_exit+0x100/0x2e0 [ 42.038544] SyS_exit_group+0x19/0x20 [ 42.042321] ? do_group_exit+0x2e0/0x2e0 [ 42.046360] do_syscall_64+0x1d5/0x640 [ 42.050227] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 42.055394] RIP: 0033:0x4450c8 [ 42.058561] RSP: 002b:00007ffea48c61c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 42.066257] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000004450c8 [ 42.073503] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 42.080868] RBP: 00000000004cce50 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 42.088114] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 42.095360] R13: 00000000006e0200 R14: 0000000000000000 R15: 0000000000000000 [ 42.102614] [ 42.104219] Allocated by task 6388: [ 42.107935] kasan_kmalloc+0xeb/0x160 [ 42.111712] kmem_cache_alloc_trace+0x131/0x3d0 [ 42.116357] hci_chan_create+0x7c/0x300 [ 42.120320] l2cap_conn_add.part.0+0x18/0xc20 [ 42.124794] l2cap_connect_cfm+0x1d2/0xce0 [ 42.129001] hci_le_meta_evt+0x3288/0x3fc0 [ 42.133212] hci_event_packet+0x19eb/0x7d1d [ 42.137509] hci_rx_work+0x3e6/0x970 [ 42.141216] process_one_work+0x793/0x14a0 [ 42.145446] worker_thread+0x5cc/0xff0 [ 42.149321] kthread+0x30d/0x420 [ 42.152664] ret_from_fork+0x24/0x30 [ 42.156351] [ 42.157952] Freed by task 1200: [ 42.161207] kasan_slab_free+0xc3/0x1a0 [ 42.165157] kfree+0xc9/0x250 [ 42.168240] hci_event_packet+0xee6/0x7d1d [ 42.172451] hci_rx_work+0x3e6/0x970 [ 42.176142] process_one_work+0x793/0x14a0 [ 42.180353] worker_thread+0x5cc/0xff0 [ 42.184232] kthread+0x30d/0x420 [ 42.187573] ret_from_fork+0x24/0x30 [ 42.191257] [ 42.192863] The buggy address belongs to the object at ffff8880926c63c0 [ 42.192863] which belongs to the cache kmalloc-128 of size 128 [ 42.205936] The buggy address is located 24 bytes inside of [ 42.205936] 128-byte region [ffff8880926c63c0, ffff8880926c6440) [ 42.217695] The buggy address belongs to the page: [ 42.222600] page:ffffea000249b180 count:1 mapcount:0 mapping:ffff8880926c6000 index:0xffff8880926c6780 [ 42.232107] flags: 0xfffe0000000100(slab) [ 42.236232] raw: 00fffe0000000100 ffff8880926c6000 ffff8880926c6780 0000000100000009 [ 42.244089] raw: ffffea0002692a20 ffffea0002376320 ffff88812fe50640 0000000000000000 [ 42.251962] page dumped because: kasan: bad access detected [ 42.257671] [ 42.259290] Memory state around the buggy address: [ 42.264194] ffff8880926c6280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 42.271529] ffff8880926c6300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.278881] >ffff8880926c6380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 42.286214] ^ [ 42.292420] ffff8880926c6400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 42.299755] ffff8880926c6480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 42.307103] ================================================================== [ 42.314437] Disabling lock debugging due to kernel taint [ 42.333974] Kernel panic - not syncing: panic_on_warn set ... [ 42.333974] [ 42.341352] CPU: 0 PID: 6385 Comm: syz-executor465 Tainted: G B 4.14.198-syzkaller #0 [ 42.350425] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.359758] Call Trace: [ 42.362328] dump_stack+0x1b2/0x283 [ 42.365935] ? l2cap_conn_del+0x670/0x670 [ 42.370058] panic+0x1f9/0x42d [ 42.373245] ? add_taint.cold+0x16/0x16 [ 42.377209] ? ___preempt_schedule+0x16/0x18 [ 42.381596] kasan_end_report+0x43/0x49 [ 42.385546] kasan_report_error.cold+0xa7/0x194 [ 42.390190] ? hci_chan_del+0x131/0x180 [ 42.394139] __asan_report_load8_noabort+0x68/0x70 [ 42.399052] ? hci_chan_del+0x131/0x180 [ 42.403010] hci_chan_del+0x131/0x180 [ 42.406798] l2cap_conn_del+0x417/0x670 [ 42.410747] ? __mutex_unlock_slowpath+0x75/0x770 [ 42.415582] ? l2cap_conn_del+0x670/0x670 [ 42.419703] l2cap_disconn_cfm+0x6b/0x80 [ 42.423740] hci_conn_hash_flush+0x114/0x220 [ 42.428128] hci_dev_do_close+0x542/0xc50 [ 42.432266] ? lock_downgrade+0x740/0x740 [ 42.436408] hci_unregister_dev+0x170/0x7a0 [ 42.440706] ? fcntl_setlk+0xdb0/0xdb0 [ 42.444572] ? vhci_close_dev+0x50/0x50 [ 42.448524] vhci_release+0x70/0xe0 [ 42.452127] __fput+0x25f/0x7a0 [ 42.455383] task_work_run+0x11f/0x190 [ 42.459264] do_exit+0xa08/0x27f0 [ 42.462694] ? mm_update_next_owner+0x5b0/0x5b0 [ 42.467336] ? vfs_write+0x319/0x4d0 [ 42.471026] ? SyS_write+0x14d/0x210 [ 42.474715] do_group_exit+0x100/0x2e0 [ 42.478578] SyS_exit_group+0x19/0x20 [ 42.482352] ? do_group_exit+0x2e0/0x2e0 [ 42.486388] do_syscall_64+0x1d5/0x640 [ 42.490272] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 42.495451] RIP: 0033:0x4450c8 [ 42.498615] RSP: 002b:00007ffea48c61c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 42.506312] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00000000004450c8 [ 42.513563] RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 [ 42.520822] RBP: 00000000004cce50 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 42.528067] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 42.535310] R13: 00000000006e0200 R14: 0000000000000000 R15: 0000000000000000 [ 42.543902] Kernel Offset: disabled [ 42.547516] Rebooting in 86400 seconds..