[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 13.429185] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.016357] random: sshd: uninitialized urandom read (32 bytes read) [ 22.589705] random: sshd: uninitialized urandom read (32 bytes read) [ 23.292719] random: sshd: uninitialized urandom read (32 bytes read) [ 31.305379] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.7' (ECDSA) to the list of known hosts. [ 36.824525] random: sshd: uninitialized urandom read (32 bytes read) 2018/06/18 13:00:47 parsed 1 programs [ 38.110000] random: cc1: uninitialized urandom read (8 bytes read) [ 38.396911] random: crng init done 2018/06/18 13:00:49 executed programs: 0 [ 38.955378] IPVS: Creating netns size=2536 id=1 [ 38.986289] IPVS: Creating netns size=2536 id=2 [ 39.020878] IPVS: Creating netns size=2536 id=3 [ 39.047126] IPVS: Creating netns size=2536 id=4 [ 39.072688] IPVS: Creating netns size=2536 id=5 [ 39.111921] IPVS: Creating netns size=2536 id=6 [ 39.126350] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.140642] IPVS: Creating netns size=2536 id=7 [ 39.160428] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.172098] IPVS: Creating netns size=2536 id=8 [ 39.265535] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.282204] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.304856] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.326101] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.419240] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.430084] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.449859] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.459339] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.467350] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.474764] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.493616] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 39.533780] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 39.556388] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.573207] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 39.594040] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 39.605803] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.620143] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.636115] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.650132] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.658813] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.666155] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.673552] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 39.680658] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.691671] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.707222] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 39.714704] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 39.729247] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 39.745316] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.758658] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 39.769197] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 39.780470] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.797874] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.805069] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.813474] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.841803] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.868993] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 39.876226] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.889711] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 39.897698] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 39.928698] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 39.936974] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 39.946703] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 39.956388] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 39.967385] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 39.978943] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 39.986772] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 40.009965] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 40.021940] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 40.032207] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 40.040953] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 40.050771] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 40.058645] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 40.068773] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 40.078281] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 40.098133] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready [ 40.104995] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 40.112838] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 40.122463] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready [ 40.130684] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 40.138437] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready [ 40.146295] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 40.154917] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 40.162389] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 40.169830] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 40.179844] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 40.189625] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready [ 40.196893] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 40.204289] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 40.215510] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready [ 40.223897] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 40.232349] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 40.244748] IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready [ 40.258318] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 40.265703] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 41.951233] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.085367] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.098472] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.106193] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 42.169634] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.281980] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.296185] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.304698] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 42.412111] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.449928] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.463639] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.493928] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.513000] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.538225] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 42.550950] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.562915] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.570204] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 42.599233] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.608316] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.615027] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 42.626582] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.638092] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.644856] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 42.659164] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.665657] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.673760] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.683662] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 42.690986] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.697939] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 42.736085] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 42.750797] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 42.757864] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 43.346825] hrtimer: interrupt took 33012 ns 2018/06/18 13:00:54 executed programs: 24 [ 46.437680] ================================================================== [ 46.445096] BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 [ 46.452362] Read of size 4 at addr ffff8801d4172280 by task syz-executor7/7857 [ 46.459704] [ 46.461321] CPU: 1 PID: 7857 Comm: syz-executor7 Not tainted 4.9.109-ga4230be #48 [ 46.468925] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.478268] ffff8801d456f878 ffffffff81eb3e29 ffffea0007505c80 ffff8801d4172280 [ 46.486305] 0000000000000000 ffff8801d4172280 ffffffff83013be0 ffff8801d456f8b0 [ 46.494326] ffffffff81567a89 ffff8801d4172280 0000000000000004 0000000000000000 [ 46.502360] Call Trace: [ 46.504939] [] dump_stack+0xc1/0x128 [ 46.510297] [] ? sock_release+0x1c0/0x1c0 [ 46.516090] [] print_address_description+0x6c/0x234 [ 46.522748] [] ? sock_release+0x1c0/0x1c0 [ 46.528536] [] kasan_report.cold.6+0x242/0x2fe [ 46.534756] [] ? l2tp_session_queue_purge+0xf4/0x100 [ 46.541495] [] __asan_report_load4_noabort+0x14/0x20 [ 46.548227] [] l2tp_session_queue_purge+0xf4/0x100 [ 46.554780] [] ? sock_release+0x1c0/0x1c0 [ 46.560557] [] pppol2tp_release+0x1fb/0x2e0 [ 46.566517] [] sock_release+0x96/0x1c0 [ 46.572038] [] sock_close+0x16/0x20 [ 46.577300] [] __fput+0x263/0x700 [ 46.582388] [] ____fput+0x15/0x20 [ 46.587476] [] task_work_run+0x10c/0x180 [ 46.593174] [] do_exit+0x9e1/0x27c0 [ 46.598437] [] ? debug_check_no_locks_freed+0x210/0x210 [ 46.605431] [] ? get_futex_key+0x1090/0x1090 [ 46.611465] [] ? release_task.part.19+0x1210/0x1210 [ 46.618118] [] ? recalc_sigpending+0x72/0x90 [ 46.624160] [] do_group_exit+0x111/0x340 [ 46.629847] [] get_signal+0x4cf/0x1450 [ 46.635359] [] do_signal+0x87/0x19f0 [ 46.640711] [] ? nf_setsockopt+0x99/0xc0 [ 46.646398] [] ? ipv6_setsockopt+0x68/0x130 [ 46.652347] [] ? setup_sigcontext+0x7d0/0x7d0 [ 46.658561] [] ? udpv6_setsockopt+0x51/0x90 [ 46.664522] [] ? do_futex+0x17c0/0x17c0 [ 46.670131] [] ? exit_to_usermode_loop+0xac/0x120 [ 46.676602] [] exit_to_usermode_loop+0xe1/0x120 [ 46.682893] [] do_syscall_64+0x364/0x490 [ 46.688579] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 46.695476] [ 46.697106] Allocated by task 7832: [ 46.700715] save_stack_trace+0x16/0x20 [ 46.704668] save_stack+0x43/0xd0 [ 46.708104] kasan_kmalloc+0xc7/0xe0 [ 46.711799] __kmalloc+0x11d/0x300 [ 46.715326] l2tp_session_create+0x38/0x16f0 [ 46.719721] pppol2tp_connect+0x10d7/0x18f0 [ 46.724025] SYSC_connect+0x1b8/0x300 [ 46.727808] SyS_connect+0x24/0x30 [ 46.731332] do_syscall_64+0x1a6/0x490 [ 46.735198] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 46.740289] [ 46.741890] Freed by task 7856: [ 46.745146] save_stack_trace+0x16/0x20 [ 46.749094] save_stack+0x43/0xd0 [ 46.752519] kasan_slab_free+0x72/0xc0 [ 46.756386] kfree+0xfb/0x310 [ 46.759473] l2tp_session_free+0x166/0x200 [ 46.763682] l2tp_tunnel_closeall+0x284/0x350 [ 46.768152] l2tp_udp_encap_destroy+0x87/0xe0 [ 46.772622] udpv6_destroy_sock+0xb1/0xd0 [ 46.776742] sk_common_release+0x6d/0x300 [ 46.780866] udp_lib_close+0x15/0x20 [ 46.784572] inet_release+0xff/0x1d0 [ 46.788262] inet6_release+0x50/0x70 [ 46.791956] sock_release+0x96/0x1c0 [ 46.795650] sock_close+0x16/0x20 [ 46.799088] __fput+0x263/0x700 [ 46.802358] ____fput+0x15/0x20 [ 46.805617] task_work_run+0x10c/0x180 [ 46.809482] do_exit+0x9e1/0x27c0 [ 46.812937] do_group_exit+0x111/0x340 [ 46.816806] SyS_exit_group+0x1d/0x20 [ 46.820596] do_syscall_64+0x1a6/0x490 [ 46.824459] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 46.829557] [ 46.831166] The buggy address belongs to the object at ffff8801d4172280 [ 46.831166] which belongs to the cache kmalloc-512 of size 512 [ 46.843796] The buggy address is located 0 bytes inside of [ 46.843796] 512-byte region [ffff8801d4172280, ffff8801d4172480) [ 46.855470] The buggy address belongs to the page: [ 46.860375] page:ffffea0007505c80 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 46.870570] flags: 0x8000000000004080(slab|head) [ 46.875304] page dumped because: kasan: bad access detected [ 46.880982] [ 46.882671] Memory state around the buggy address: [ 46.887591] ffff8801d4172180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.894931] ffff8801d4172200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 46.902267] >ffff8801d4172280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.909598] ^ [ 46.912939] ffff8801d4172300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.920274] ffff8801d4172380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.927609] ================================================================== [ 46.934939] Disabling lock debugging due to kernel taint [ 46.940789] Kernel panic - not syncing: panic_on_warn set ... [ 46.940789] [ 46.948151] CPU: 1 PID: 7857 Comm: syz-executor7 Tainted: G B 4.9.109-ga4230be #48 [ 46.956965] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.966299] ffff8801d456f7d8 ffffffff81eb3e29 ffffffff843c6327 00000000ffffffff [ 46.974333] 0000000000000000 0000000000000001 ffffffff83013be0 ffff8801d456f898 [ 46.982339] ffffffff81421925 0000000041b58ab3 ffffffff843b9a40 ffffffff81421766 [ 46.990368] Call Trace: [ 46.992953] [] dump_stack+0xc1/0x128 [ 46.998301] [] ? sock_release+0x1c0/0x1c0 [ 47.004079] [] panic+0x1bf/0x3bc [ 47.009074] [] ? add_taint.cold.6+0x16/0x16 [ 47.015029] [] ? ___preempt_schedule+0x16/0x18 [ 47.021240] [] kasan_end_report+0x47/0x4f [ 47.027015] [] kasan_report.cold.6+0x76/0x2fe [ 47.033157] [] ? l2tp_session_queue_purge+0xf4/0x100 [ 47.039890] [] __asan_report_load4_noabort+0x14/0x20 [ 47.046631] [] l2tp_session_queue_purge+0xf4/0x100 [ 47.053191] [] ? sock_release+0x1c0/0x1c0 [ 47.058969] [] pppol2tp_release+0x1fb/0x2e0 [ 47.064924] [] sock_release+0x96/0x1c0 [ 47.070440] [] sock_close+0x16/0x20 [ 47.075696] [] __fput+0x263/0x700 [ 47.080779] [] ____fput+0x15/0x20 [ 47.085865] [] task_work_run+0x10c/0x180 [ 47.091557] [] do_exit+0x9e1/0x27c0 [ 47.096817] [] ? debug_check_no_locks_freed+0x210/0x210 [ 47.103813] [] ? get_futex_key+0x1090/0x1090 [ 47.109854] [] ? release_task.part.19+0x1210/0x1210 [ 47.116504] [] ? recalc_sigpending+0x72/0x90 [ 47.122544] [] do_group_exit+0x111/0x340 [ 47.128247] [] get_signal+0x4cf/0x1450 [ 47.133777] [] do_signal+0x87/0x19f0 [ 47.139123] [] ? nf_setsockopt+0x99/0xc0 [ 47.144814] [] ? ipv6_setsockopt+0x68/0x130 [ 47.150768] [] ? setup_sigcontext+0x7d0/0x7d0 [ 47.156892] [] ? udpv6_setsockopt+0x51/0x90 [ 47.162848] [] ? do_futex+0x17c0/0x17c0 [ 47.168453] [] ? exit_to_usermode_loop+0xac/0x120 [ 47.174925] [] exit_to_usermode_loop+0xe1/0x120 [ 47.181224] [] do_syscall_64+0x364/0x490 [ 47.186928] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 47.194340] Dumping ftrace buffer: [ 47.197867] (ftrace buffer empty) [ 47.201549] Kernel Offset: disabled [ 47.205148] Rebooting in 86400 seconds..