[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.746307] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [ 21.060799] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available) [ 21.361218] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.315909] random: sshd: uninitialized urandom read (32 bytes read, 99 bits of entropy available) [ 22.493666] random: sshd: uninitialized urandom read (32 bytes read, 103 bits of entropy available) Warning: Permanently added '10.128.0.53' (ECDSA) to the list of known hosts. [ 27.888273] random: sshd: uninitialized urandom read (32 bytes read, 112 bits of entropy available) executing program [ 27.986925] ================================================================== [ 27.994327] BUG: KASAN: use-after-free in ip6_xmit+0x1a2c/0x1a70 [ 28.000443] Read of size 8 at addr ffff8800b61d2658 by task syzkaller610588/3779 [ 28.007939] [ 28.009539] CPU: 0 PID: 3779 Comm: syzkaller610588 Not tainted 4.4.119-g024f962 #26 [ 28.017296] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.026618] 0000000000000000 8677f3bc780bc4d7 ffff8801c4e3f7e0 ffffffff81d0402d [ 28.034582] ffffea0002d87480 ffff8800b61d2658 0000000000000000 ffff8800b61d2658 [ 28.042550] 0000000000000040 ffff8801c4e3f818 ffffffff814fe103 ffff8800b61d2658 [ 28.050511] Call Trace: [ 28.053067] [] dump_stack+0xc1/0x124 [ 28.058403] [] print_address_description+0x73/0x260 [ 28.065037] [] kasan_report+0x285/0x370 [ 28.070631] [] ? ip6_xmit+0x1a2c/0x1a70 [ 28.076231] [] __asan_report_load8_noabort+0x14/0x20 [ 28.082952] [] ip6_xmit+0x1a2c/0x1a70 [ 28.088375] [] ? kfree+0xfc/0x300 [ 28.093447] [] ? pskb_expand_head+0x28b/0x980 [ 28.099559] [] ? l2tp_xmit_skb+0xa5e/0xea0 [ 28.105409] [] ? ip6_finish_output2+0x1c60/0x1c60 [ 28.111868] [] ? __lock_is_held+0xa1/0xf0 [ 28.117636] [] ? ipv4_dst_check+0x111/0x160 [ 28.123572] [] ? __sk_dst_check+0x148/0x260 [ 28.129513] [] inet6_csk_xmit+0x246/0x480 [ 28.135277] [] ? inet6_csk_xmit+0x100/0x480 [ 28.141217] [] ? inet6_csk_update_pmtu+0x160/0x160 [ 28.147776] [] ? udp6_set_csum+0x336/0xa80 [ 28.153629] [] l2tp_xmit_skb+0xc2f/0xea0 [ 28.159317] [] pppol2tp_sendmsg+0x584/0x7f0 [ 28.165259] [] ? selinux_socket_sendmsg+0x3f/0x50 [ 28.171720] [] ? pppol2tp_release+0x310/0x310 [ 28.177831] [] sock_sendmsg+0xca/0x110 [ 28.183335] [] SYSC_sendto+0x2c8/0x340 [ 28.188842] [] ? SYSC_connect+0x310/0x310 [ 28.194606] [] ? lock_sock_nested+0xdc/0x120 [ 28.200630] [] ? ip6_datagram_connect+0x3a/0x50 [ 28.206920] [] ? inet_dgram_connect+0x172/0x1f0 [ 28.213205] [] ? SYSC_connect+0x212/0x310 [ 28.218972] [] ? __do_page_fault+0x380/0xa00 [ 28.225002] [] ? retint_user+0x18/0x3c [ 28.230507] [] SyS_sendto+0x40/0x50 [ 28.235753] [] entry_SYSCALL_64_fastpath+0x1c/0x98 [ 28.242296] [ 28.243892] Allocated by task 3762: [ 28.247485] [] save_stack_trace+0x26/0x50 [ 28.253369] [] save_stack+0x43/0xd0 [ 28.258731] [] kasan_kmalloc+0xad/0xe0 [ 28.264351] [] kasan_slab_alloc+0x12/0x20 [ 28.270232] [] kmem_cache_alloc+0xba/0x290 [ 28.276199] [] dst_alloc+0x11f/0x1a0 [ 28.281643] [] rt_dst_alloc+0x78/0x430 [ 28.287261] [] __ip_route_output_key_hash+0xa4e/0x2390 [ 28.294270] [] __ip4_datagram_connect+0xa15/0x1150 [ 28.300936] [] __ip6_datagram_connect+0x4d9/0x1950 [ 28.307598] [] ip6_datagram_connect+0x2f/0x50 [ 28.313830] [] inet_dgram_connect+0x16b/0x1f0 [ 28.320062] [] SYSC_connect+0x1b6/0x310 [ 28.325768] [] SyS_connect+0x24/0x30 [ 28.331212] [] entry_SYSCALL_64_fastpath+0x1c/0x98 [ 28.337872] [ 28.339468] Freed by task 0: [ 28.342453] [] save_stack_trace+0x26/0x50 [ 28.348334] [] save_stack+0x43/0xd0 [ 28.353693] [] kasan_slab_free+0x72/0xc0 [ 28.359486] [] kmem_cache_free+0xc7/0x320 [ 28.365367] [] dst_destroy+0x20e/0x330 [ 28.370989] [] dst_destroy_rcu+0x15/0x40 [ 28.376785] [] rcu_process_callbacks+0x7f4/0x14a0 [ 28.383361] [] __do_softirq+0x227/0xa38 [ 28.389070] [ 28.390665] The buggy address belongs to the object at ffff8800b61d2640 [ 28.390665] which belongs to the cache ip_dst_cache of size 208 [ 28.403374] The buggy address is located 24 bytes inside of [ 28.403374] 208-byte region [ffff8800b61d2640, ffff8800b61d2710) [ 28.415124] The buggy address belongs to the page: [ 29.787225] PANIC: double fault, error_code: 0x0 [ 29.792012] CPU: 0 PID: 3779 Comm: syzkaller610588 Not tainted 4.4.119-g024f962 #26 [ 29.799773] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.809095] task: ffff8801c6b6e000 task.stack: ffff8801c4e38000 [ 29.815118] RIP: 0010:[] [] dump_page_badflags+0x4/0x250 [ 29.823875] RSP: 0018:ffff880100000000 EFLAGS: 00010046 [ 29.829291] RAX: ffff8801c6b6e000 RBX: ffffea0002d87480 RCX: ffffffff81490970 [ 29.836541] RDX: 0000000000000000 RSI: ffffffff838a9060 RDI: ffffea0002d87480 [ 29.843779] RBP: ffff880100000000 R08: 0000000000000001 R09: 0000000000000000 [ 29.851016] R10: 0000000000000002 R11: fffffbfff0ad7e1e R12: 0000000000000000 [ 29.858256] R13: ffffffff838a9060 R14: 0000000000000000 R15: 0000000000000000 [ 29.865497] FS: 0000000001513880(0063) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 29.873691] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 29.879539] CR2: ffff8800fffffff8 CR3: 00000001c97ee000 CR4: 0000000000160670 [ 29.886780] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 29.894028] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 29.901265] Stack: [ 29.903380] [ 29.904974] Call Trace: [ 29.907524] [ 29.909550] Code: e8 92 df 06 00 e9 83 fd ff ff e8 88 df 06 00 e9 50 fd ff ff e8 7e df 06 00 e9 1d fd ff ff 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 <41> 57 41 56 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb 48 83 ec [ 29.936551] Kernel panic - not syncing: Machine halted. [ 29.941884] CPU: 0 PID: 3779 Comm: syzkaller610588 Not tainted 4.4.119-g024f962 #26 [ 29.949655] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.958983] 0000000000000000 8677f3bc780bc4d7 ffff8801db20ce38 ffffffff81d0402d [ 29.966961] ffffffff838373a0 ffff8801db20cf10 ffffffff83808040 ffff880100000000 [ 29.974924] 0000000000000000 ffff8801db20cf00 ffffffff8141aaea 0000000041b58ab3 [ 29.982889] Call Trace: [ 29.985442] <#DF> [] dump_stack+0xc1/0x124 [ 29.991515] [] panic+0x1aa/0x388 [ 29.996506] [] ? percpu_up_read.constprop.45+0xe1/0xe1 [ 30.003407] [] ? vprintk_emit+0x242/0x850 [ 30.009173] [] ? dump_page_badflags+0x19/0x250 [ 30.015375] [] ? vprintk_emit+0x242/0x850 [ 30.021144] [] df_debug+0x2d/0x30 [ 30.026227] [] do_double_fault+0x10b/0x210 [ 30.032080] [] double_fault+0x2d/0x40 [ 30.037510] [] ? dump_page_badflags+0x180/0x250 [ 30.043796] [] ? dump_page_badflags+0x4/0x250 [ 30.049905] <> [ 30.053457] Dumping ftrace buffer: [ 30.057308] (ftrace buffer empty) [ 30.060988] Kernel Offset: disabled [ 30.064596] Rebooting in 86400 seconds..