[ 16.459927] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.158740] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 20.529262] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 21.476289] random: sshd: uninitialized urandom read (32 bytes read, 111 bits of entropy available) [ 21.650938] random: sshd: uninitialized urandom read (32 bytes read, 117 bits of entropy available) Warning: Permanently added '10.128.0.49' (ECDSA) to the list of known hosts. [ 27.051247] random: sshd: uninitialized urandom read (32 bytes read, 125 bits of entropy available) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 27.766222] random: nonblocking pool is initialized executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 31.481543] l2tp_core: tunl 3: sockfd_lookup(fd=3) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.601232] ================================================================== [ 34.608610] BUG: KASAN: use-after-free in pppol2tp_session_destruct+0xee/0x110 [ 34.615941] Read of size 4 at addr ffff8800ba1faf00 by task syzkaller736210/8777 [ 34.623448] [ 34.625046] CPU: 0 PID: 8777 Comm: syzkaller736210 Not tainted 4.4.113-gef588ef #33 [ 34.632808] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.642131] 0000000000000000 63cefcad2ad57849 ffff8800ba14fc68 ffffffff81d0278d [ 34.650095] ffffea0002e87e80 ffff8800ba1faf00 0000000000000000 ffff8800ba1faf00 [ 34.658059] ffffffff82de6370 ffff8800ba14fca0 ffffffff814fd053 ffff8800ba1faf00 [ 34.666023] Call Trace: [ 34.668580] [] dump_stack+0xc1/0x124 [ 34.673913] [] ? sock_release+0x1e0/0x1e0 [ 34.679681] [] print_address_description+0x73/0x260 [ 34.686315] [] ? sock_release+0x1e0/0x1e0 [ 34.692079] [] kasan_report+0x285/0x370 [ 34.697670] [] ? pppol2tp_session_destruct+0xee/0x110 [ 34.704477] [] __asan_report_load4_noabort+0x14/0x20 [ 34.711196] [] pppol2tp_session_destruct+0xee/0x110 [ 34.717827] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 34.724113] [] sk_destruct+0x4a/0x4c0 [ 34.729535] [] __sk_free+0x57/0x230 [ 34.734781] [] sk_free+0x30/0x40 [ 34.739765] [] pppol2tp_release+0x27a/0x310 [ 34.745706] [] sock_release+0x8d/0x1e0 [ 34.751211] [] sock_close+0x16/0x20 [ 34.756457] [] __fput+0x233/0x6d0 [ 34.761530] [] ____fput+0x15/0x20 [ 34.766604] [] task_work_run+0x104/0x180 [ 34.772281] [] exit_to_usermode_loop+0x13d/0x160 [ 34.778652] [] syscall_return_slowpath+0x1b5/0x1f0 [ 34.785197] [] int_ret_from_sys_call+0x25/0xa3 [ 34.791394] [ 34.792989] Allocated by task 8776: [ 34.796582] [] save_stack_trace+0x26/0x50 [ 34.802467] [] save_stack+0x43/0xd0 [ 34.807832] [] kasan_kmalloc+0xad/0xe0 [ 34.813452] [] __kmalloc+0x124/0x320 [ 34.818900] [] l2tp_session_create+0x39/0x10f0 [ 34.825222] [] pppol2tp_connect+0x10fc/0x1930 [ 34.831459] [] SYSC_connect+0x1b6/0x310 [ 34.837164] [] SyS_connect+0x24/0x30 [ 34.842614] [] entry_SYSCALL_64_fastpath+0x1c/0x98 [ 34.849281] [ 34.850880] Freed by task 8776: [ 34.854125] [] save_stack_trace+0x26/0x50 [ 34.860008] [] save_stack+0x43/0xd0 [ 34.865378] [] kasan_slab_free+0x72/0xc0 [ 34.871188] [] kfree+0xfc/0x300 [ 34.876214] [] l2tp_session_free+0x170/0x200 [ 34.882368] [] l2tp_tunnel_closeall+0x2d1/0x3b0 [ 34.888784] [] l2tp_udp_encap_destroy+0x8b/0xf0 [ 34.895192] [] udpv6_destroy_sock+0xb1/0xd0 [ 34.901248] [] sk_common_release+0x6b/0x300 [ 34.907306] [] udp_lib_close+0x15/0x20 [ 34.913029] [] inet_release+0xfa/0x1d0 [ 34.918653] [] inet6_release+0x50/0x70 [ 34.924278] [] sock_release+0x8d/0x1e0 [ 34.929899] [] sock_close+0x16/0x20 [ 34.935274] [] __fput+0x233/0x6d0 [ 34.940465] [] ____fput+0x15/0x20 [ 34.945653] [] task_work_run+0x104/0x180 [ 34.951450] [] exit_to_usermode_loop+0x13d/0x160 [ 34.957940] [] syscall_return_slowpath+0x1b5/0x1f0 [ 34.964602] [] int_ret_from_sys_call+0x25/0xa3 [ 34.970917] [ 34.972517] The buggy address belongs to the object at ffff8800ba1faf00 [ 34.972517] which belongs to the cache kmalloc-512 of size 512 [ 34.985142] The buggy address is located 0 bytes inside of [ 34.985142] 512-byte region [ffff8800ba1faf00, ffff8800ba1fb100) [ 34.996809] The buggy address belongs to the page: [ 35.019556] kasan: CONFIG_KASAN_INLINE enabled [ 35.023989] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN [ 35.036897] Dumping ftrace buffer: [ 35.040423] (ftrace buffer empty) [ 35.044120] Modules linked in: [ 35.047436] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.113-gef588ef #33 [ 35.054432] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.063779] task: ffff8801da3a97c0 task.stack: ffff8801da3b8000 [ 35.069830] RIP: 0010:[] [] rb_insert_color+0x7b/0xcb0 [ 35.078463] RSP: 0018:ffff8801db307d18 EFLAGS: 00010002 [ 35.083908] RAX: 0000000000000008 RBX: 0000000000000000 RCX: 0000000000000000 [ 35.091170] RDX: 0000000000000001 RSI: ffff8801db319710 RDI: ffff8801db319c40 [ 35.098434] RBP: ffff8801db307d60 R08: ffffffff857d3748 R09: 0000000000000001 [ 35.105701] R10: 0000000000000000 R11: 1ffff1003b660f62 R12: ffff8800b7c47df8 [ 35.112989] R13: 0000000000000000 R14: ffff8801db319c40 R15: dffffc0000000000 [ 35.120261] FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 35.128486] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 35.134369] CR2: 0000000020e71000 CR3: 00000000baa5e000 CR4: 0000000000160670 [ 35.141640] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 35.148901] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 35.156163] Stack: [ 35.158305] ffffffff842bdb20 ffff8801da3aa030 0000000000000000 ffff8801db307d70 [ 35.166363] ffff8801db319c40 dffffc0000000000 0000000000000000 ffff8801db319710 [ 35.174410] ffff8800b7c47e00 ffff8801db307db0 ffffffff81d20067 ffff8801db319c58 [ 35.182454] Call Trace: [ 35.185021] [ 35.187088] [] timerqueue_add+0x157/0x2a0 [ 35.193188] [] enqueue_hrtimer+0x168/0x450 [ 35.199081] [] __hrtimer_run_queues+0x732/0xfe0 [ 35.205401] [] ? hrtimer_fixup_init+0x70/0x70 [ 35.211549] [] ? hrtimer_interrupt+0x131/0x440 [ 35.217778] [] hrtimer_interrupt+0x1a6/0x440 [ 35.223838] [] local_apic_timer_interrupt+0x6a/0xb0 [ 35.230525] [] smp_apic_timer_interrupt+0x76/0xa0 [ 35.237015] [] apic_timer_interrupt+0xa0/0xb0 [ 35.243152] [ 35.245225] [] ? native_safe_halt+0x6/0x10 [ 35.251416] [] ? trace_hardirqs_on+0xd/0x10 [ 35.258379] [] default_idle+0x55/0x3c0 [ 35.263915] [] arch_cpu_idle+0xa/0x10 [ 35.269366] [] default_idle_call+0x48/0x70 [ 35.275252] [] cpu_startup_entry+0x5fd/0x8f0 [ 35.281319] [] ? call_cpuidle+0xe0/0xe0 [ 35.286951] [] ? clockevents_register_device+0x122/0x230 [ 35.294064] [] start_secondary+0x304/0x3e0 [ 35.299972] [] ? set_cpu_sibling_map+0x1080/0x1080 [ 35.306544] Code: 0f 85 06 0a 00 00 49 bf 00 00 00 00 00 fc ff df 49 8b 1c 24 f6 c3 01 0f 85 9a 01 00 00 48 8d 43 08 48 89 d9 48 89 c2 48 c1 ea 03 <42> 80 3c 3a 00 0f 85 94 09 00 00 4c 8b 6b 08 4d 39 e5 0f 84 b0 [ 35.334130] RIP [] rb_insert_color+0x7b/0xcb0 [ 35.340402] RSP [ 35.344022] ---[ end trace 56da76a1cbf15bfc ]--- [ 35.348770] Kernel panic - not syncing: Fatal exception in interrupt [ 36.461440] Shutting down cpus with NMI [ 36.465898] Dumping ftrace buffer: [ 36.469419] (ftrace buffer empty) [ 36.473100] Kernel Offset: disabled [ 36.476701] Rebooting in 86400 seconds..