[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 16.216265] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.348202] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 20.975457] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 21.836829] random: sshd: uninitialized urandom read (32 bytes read, 104 bits of entropy available) [ 22.016372] random: sshd: uninitialized urandom read (32 bytes read, 109 bits of entropy available) Warning: Permanently added '10.128.15.229' (ECDSA) to the list of known hosts. [ 27.399185] random: sshd: uninitialized urandom read (32 bytes read, 117 bits of entropy available) executing program [ 27.498858] ================================================================== [ 27.506236] BUG: KASAN: use-after-free in ip6_xmit+0x193a/0x1ad0 [ 27.512350] Read of size 8 at addr ffff8801d58e03d8 by task syzkaller880654/3328 [ 27.519850] [ 27.521448] CPU: 0 PID: 3328 Comm: syzkaller880654 Not tainted 4.4.112-g3fc4284 #32 [ 27.529204] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.538525] 0000000000000000 822461627fab6c6f ffff8801d0a775b8 ffffffff81d054ed [ 27.546479] ffffea0007563800 ffff8801d58e03d8 0000000000000000 ffff8801d58e03d8 [ 27.554440] 0000000000000040 ffff8801d0a775f0 ffffffff814fd953 ffff8801d58e03d8 [ 27.562402] Call Trace: [ 27.564958] [] dump_stack+0xc1/0x124 [ 27.570291] [] print_address_description+0x73/0x260 [ 27.576926] [] kasan_report+0x285/0x370 [ 27.582516] [] ? ip6_xmit+0x193a/0x1ad0 [ 27.588107] [] __asan_report_load8_noabort+0x14/0x20 [ 27.594827] [] ip6_xmit+0x193a/0x1ad0 [ 27.600245] [] ? save_trace+0xe0/0x270 [ 27.605749] [] ? pskb_expand_head+0x28b/0x980 [ 27.611860] [] ? ip6_finish_output2+0x1c60/0x1c60 [ 27.618327] [] ? __lock_is_held+0xa1/0xf0 [ 27.624093] [] ? ipv4_dst_check+0x111/0x160 [ 27.630040] [] ? __sk_dst_check+0x148/0x260 [ 27.635985] [] inet6_csk_xmit+0x246/0x480 [ 27.641747] [] ? inet6_csk_xmit+0x100/0x480 [ 27.647690] [] ? inet6_csk_update_pmtu+0x160/0x160 [ 27.654234] [] ? udp6_set_csum+0x336/0xa80 [ 27.660084] [] l2tp_xmit_skb+0xc2f/0xea0 [ 27.665763] [] pppol2tp_sendmsg+0x584/0x7f0 [ 27.671715] [] ? selinux_socket_sendmsg+0x3f/0x50 [ 27.678200] [] ? pppol2tp_release+0x310/0x310 [ 27.684314] [] sock_sendmsg+0xca/0x110 [ 27.689820] [] ___sys_sendmsg+0x312/0x7c0 [ 27.695584] [] ? copy_msghdr_from_user+0x550/0x550 [ 27.702131] [] ? release_pages+0x1f7/0x4f0 [ 27.707982] [] ? put_pages_list+0xb0/0xb0 [ 27.713748] [] ? _raw_spin_unlock_irqrestore+0x5a/0x70 [ 27.720645] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 27.727451] [] ? pagevec_lru_move_fn+0x1c5/0x250 [ 27.733826] [] ? __put_single_page+0x60/0x60 [ 27.739855] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 27.746573] [] ? __fget_light+0xa1/0x1e0 [ 27.752254] [] ? __fdget+0x18/0x20 [ 27.757415] [] ? sockfd_lookup_light+0x118/0x160 [ 27.763788] [] __sys_sendmmsg+0x11c/0x2e0 [ 27.769557] [] ? SyS_sendmsg+0x50/0x50 [ 27.775849] [] ? handle_mm_fault+0x3f2/0x3190 [ 27.781975] [] ? SYSC_connect+0x212/0x310 [ 27.787740] [] ? SYSC_bind+0x280/0x280 [ 27.793245] [] ? __do_page_fault+0x380/0xa00 [ 27.799271] [] ? retint_user+0x18/0x3c [ 27.804779] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 27.811593] [] SyS_sendmmsg+0x35/0x60 [ 27.817012] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 27.823555] [ 27.825150] Allocated by task 3272: [ 27.828742] [] save_stack_trace+0x26/0x50 [ 27.834625] [] save_stack+0x43/0xd0 [ 27.839985] [] kasan_kmalloc+0xad/0xe0 [ 27.845603] [] kasan_slab_alloc+0x12/0x20 [ 27.851481] [] kmem_cache_alloc+0xba/0x290 [ 27.857448] [] dst_alloc+0x11f/0x1a0 [ 27.862894] [] rt_dst_alloc+0x78/0x430 [ 27.868513] [] __ip_route_output_key_hash+0xa4e/0x2390 [ 27.875527] [] __ip4_datagram_connect+0xa15/0x1150 [ 27.882208] [] __ip6_datagram_connect+0x4d9/0x1950 [ 27.888872] [] ip6_datagram_connect+0x2f/0x50 [ 27.895098] [] inet_dgram_connect+0x16b/0x1f0 [ 27.901324] [] SYSC_connect+0x1b6/0x310 [ 27.907030] [] SyS_connect+0x24/0x30 [ 27.912472] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 27.919225] [ 27.920824] Freed by task 3198: [ 27.924065] [] save_stack_trace+0x26/0x50 [ 27.929958] [] save_stack+0x43/0xd0 [ 27.935320] [] kasan_slab_free+0x72/0xc0 [ 27.941115] [] kmem_cache_free+0xc7/0x320 [ 27.946995] [] dst_destroy+0x20e/0x330 [ 27.952616] [] dst_destroy_rcu+0x15/0x40 [ 27.958407] [] rcu_process_callbacks+0x7f8/0x14b0 [ 27.964982] [] __do_softirq+0x24d/0xa59 [ 27.970702] [ 27.972299] The buggy address belongs to the object at ffff8801d58e03c0 [ 27.972299] which belongs to the cache ip_dst_cache of size 208 [ 27.985010] The buggy address is located 24 bytes inside of [ 27.985010] 208-byte region [ffff8801d58e03c0, ffff8801d58e0490) [ 27.996765] The buggy address belongs to the page: [ 29.487070] PANIC: double fault, error_code: 0x0 [ 29.491838] CPU: 0 PID: 3328 Comm: syzkaller880654 Not tainted 4.4.112-g3fc4284 #32 [ 29.499605] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.508929] task: ffff8800b5f9df00 task.stack: ffff8801d0a70000 [ 29.514952] RIP: 0010:[] [] dump_page_badflags+0xd/0x250 [ 29.523701] RSP: 0018:ffff880100000000 EFLAGS: 00010046 [ 29.529117] RAX: ffff8800b5f9df00 RBX: ffffea0007563800 RCX: ffffffff8148fea0 [ 29.536357] RDX: 0000000000000000 RSI: ffffffff838a8620 RDI: ffffea0007563800 [ 29.543600] RBP: ffff880100000018 R08: 0000000000000001 R09: 0000000000000000 [ 29.550837] R10: 0000000000000002 R11: fffffbfff0ad7a1e R12: 0000000000000000 [ 29.558073] R13: ffffffff838a8620 R14: 0000000000000000 R15: 0000000000000000 [ 29.565320] FS: 0000000000e69880(0063) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 29.573518] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 29.579368] CR2: ffff8800fffffff8 CR3: 00000001d0ed6000 CR4: 0000000000160670 [ 29.586608] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 29.593846] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 29.601083] Stack: [ 29.603203] [ 29.604798] Call Trace: [ 29.607349] [ 29.609375] Code: ff e8 a8 e2 06 00 e9 50 fd ff ff e8 9e e2 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 08 e8 11 01 ed ff 48 8d 7b [ 29.636287] Kernel panic - not syncing: Machine halted. [ 29.641619] CPU: 0 PID: 3328 Comm: syzkaller880654 Not tainted 4.4.112-g3fc4284 #32 [ 29.649377] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.658697] 0000000000000000 822461627fab6c6f ffff8801db20ce38 ffffffff81d054ed [ 29.666663] ffffffff83836a60 ffff8801db20cf10 ffffffff83808040 ffff880100000000 [ 29.674621] 0000000000000000 ffff8801db20cf00 ffffffff81419dca 0000000041b58ab3 [ 29.682585] Call Trace: [ 29.685132] <#DF> [] dump_stack+0xc1/0x124 [ 29.691199] [] panic+0x1aa/0x388 [ 29.696184] [] ? percpu_up_read.constprop.45+0xe1/0xe1 [ 29.703078] [] ? vprintk_emit+0x242/0x850 [ 29.708842] [] ? dump_page_badflags+0x22/0x250 [ 29.715041] [] ? vprintk_emit+0x242/0x850 [ 29.720808] [] df_debug+0x2d/0x30 [ 29.725877] [] do_double_fault+0x10b/0x210 [ 29.731729] [] double_fault+0x2d/0x40 [ 29.737153] [] ? dump_page_badflags+0x180/0x250 [ 29.743437] [] ? dump_page_badflags+0xd/0x250 [ 29.749547] <> [ 29.753118] Dumping ftrace buffer: [ 29.757010] (ftrace buffer empty) [ 29.760691] Kernel Offset: disabled [ 29.764297] Rebooting in 86400 seconds..