[ 16.853774] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 21.646869] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 22.126281] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 23.029079] random: sshd: uninitialized urandom read (32 bytes read, 112 bits of entropy available) [ 52.430998] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.7' (ECDSA) to the list of known hosts. net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz0.router_solicitations = 0 [ 74.356508] IPVS: Creating netns size=2552 id=1 RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported Cannot find device "bridge0" Cannot find device "bridge0" Cannot find device "bridge0" Cannot find device "bridge0" Cannot find device "vcan0" Cannot find device "vcan0" Cannot find device "vcan0" Cannot find device "vcan0" RTNETLINK answers: Operation not supported Cannot find device "gre0" Cannot find device "gre0" Cannot find device "gre0" Cannot find device "gre0" Cannot find device "gretap0" Cannot find device "gretap0" Cannot find device "gretap0" Cannot find device "gretap0" Cannot find device "ip_vti0" Cannot find device "ip_vti0" Cannot find device "ip_vti0" Cannot find device "ip_vti0" Cannot find device "ip6_vti0" Cannot find device "ip6_vti0" Cannot find device "ip6_vti0" Cannot find device "ip6_vti0" Cannot find device "ip6tnl0" Cannot find device "ip6tnl0" Cannot find device "ip6tnl0" Cannot find device "ip6tnl0" Cannot find device "ip6gre0" Cannot find device "ip6gre0" Cannot find device "ip6gre0" Cannot find device "ip6gre0" Cannot find device "ip6gretap0" Cannot find device "ip6gretap0" Cannot find device "ip6gretap0" Cannot find device "ip6gretap0" Cannot find device "erspan0" Cannot find device "erspan0" Cannot find device "erspan0" Cannot find device "erspan0" executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 75.569561] l2tp_core: tunl 3: fd 125 wrong protocol, got 1, expected 17 executing program executing program executing program [ 75.687147] ================================================================== [ 75.694538] BUG: KASAN: use-after-free in pppol2tp_session_destruct+0xee/0x110 [ 75.701868] Read of size 4 at addr ffff8800b5d29680 by task syzkaller230323/3476 [ 75.709372] [ 75.710979] CPU: 1 PID: 3476 Comm: syzkaller230323 Not tainted 4.4.113-ge70c132 #27 [ 75.718739] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.728060] 0000000000000000 1ccba3ef7d86deef ffff8801cee97c20 ffffffff81d0278d [ 75.736024] ffffea0002d74a00 ffff8800b5d29680 0000000000000000 ffff8800b5d29680 [ 75.743993] ffffffff82de6370 ffff8801cee97c58 ffffffff814fd053 ffff8800b5d29680 [ 75.751951] Call Trace: [ 75.754507] [] dump_stack+0xc1/0x124 [ 75.759839] [] ? sock_release+0x1e0/0x1e0 [ 75.765604] [] print_address_description+0x73/0x260 [ 75.772235] [] ? sock_release+0x1e0/0x1e0 [ 75.778000] [] kasan_report+0x285/0x370 [ 75.783593] [] ? pppol2tp_session_destruct+0xee/0x110 [ 75.790398] [] __asan_report_load4_noabort+0x14/0x20 [ 75.797118] [] pppol2tp_session_destruct+0xee/0x110 [ 75.803761] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 75.810051] [] sk_destruct+0x4a/0x4c0 [ 75.815467] [] __sk_free+0x57/0x230 [ 75.820708] [] sk_free+0x30/0x40 [ 75.825691] [] pppol2tp_release+0x27a/0x310 [ 75.831628] [] sock_release+0x8d/0x1e0 [ 75.837130] [] sock_close+0x16/0x20 [ 75.842375] [] __fput+0x233/0x6d0 [ 75.847448] [] ____fput+0x15/0x20 [ 75.852519] [] task_work_run+0x104/0x180 [ 75.858202] [] exit_to_usermode_loop+0x13d/0x160 [ 75.864675] [] do_fast_syscall_32+0x607/0x890 [ 75.870788] [] sysenter_flags_fixed+0xd/0x17 [ 75.876810] [ 75.878408] Allocated by task 3476: [ 75.882007] [] save_stack_trace+0x26/0x50 [ 75.887889] [] save_stack+0x43/0xd0 [ 75.893248] [] kasan_kmalloc+0xad/0xe0 [ 75.898867] [] __kmalloc+0x124/0x320 [ 75.904312] [] l2tp_session_create+0x39/0x10f0 [ 75.910625] [] pppol2tp_connect+0x10fc/0x1930 [ 75.916852] [] SYSC_connect+0x1b6/0x310 [ 75.922558] [] SyS_connect+0x24/0x30 [ 75.928000] [] do_fast_syscall_32+0x314/0x890 [ 75.934226] [] sysenter_flags_fixed+0xd/0x17 [ 75.940380] [ 75.941975] Freed by task 3477: [ 75.945218] [] save_stack_trace+0x26/0x50 [ 75.951098] [] save_stack+0x43/0xd0 [ 75.956466] [] kasan_slab_free+0x72/0xc0 [ 75.962274] [] kfree+0xfc/0x300 [ 75.967283] [] l2tp_session_free+0x170/0x200 [ 75.975285] [] l2tp_tunnel_closeall+0x2d1/0x3b0 [ 75.981684] [] l2tp_udp_encap_destroy+0x8b/0xf0 [ 75.988083] [] udpv6_destroy_sock+0xb1/0xd0 [ 75.994137] [] sk_common_release+0x6b/0x300 [ 76.000196] [] udp_lib_close+0x15/0x20 [ 76.005813] [] inet_release+0xfa/0x1d0 [ 76.011430] [] inet6_release+0x50/0x70 [ 76.017051] [] sock_release+0x8d/0x1e0 [ 76.022685] [] sock_close+0x16/0x20 [ 76.028039] [] __fput+0x233/0x6d0 [ 76.033223] [] ____fput+0x15/0x20 [ 76.038412] [] task_work_run+0x104/0x180 [ 76.044205] [] exit_to_usermode_loop+0x13d/0x160 [ 76.051234] [] do_fast_syscall_32+0x607/0x890 [ 76.057459] [] sysenter_flags_fixed+0xd/0x17 [ 76.063599] [ 76.065195] The buggy address belongs to the object at ffff8800b5d29680 [ 76.065195] which belongs to the cache kmalloc-512 of size 512 [ 76.077825] The buggy address is located 0 bytes inside of [ 76.077825] 512-byte region [ffff8800b5d29680, ffff8800b5d29880) [ 76.089491] The buggy address belongs to the page: [ 77.088827] kasan: CONFIG_KASAN_INLINE enabled [ 77.093264] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN [ 77.106102] Dumping ftrace buffer: [ 77.109609] (ftrace buffer empty) [ 77.113984] Modules linked in: [ 77.117264] CPU: 0 PID: 3477 Comm: syzkaller230323 Not tainted 4.4.113-ge70c132 #27 [ 77.125022] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 77.134354] task: ffff8801d2a997c0 task.stack: ffff8801d2988000 [ 77.140378] RIP: 0010:[] [] rb_erase+0x626/0x1b60 [ 77.148527] RSP: 0018:ffff8801db207d38 EFLAGS: 00010806 [ 77.154032] RAX: ffff8801d16c7e00 RBX: ffff8801d16c7df8 RCX: 1d1a89b13fffffe4 [ 77.161271] RDX: ffffed003b6432e2 RSI: ffff8801db219710 RDI: ffffffff8148f8e9 [ 77.168509] RBP: ffff8801db207d80 R08: 1ffff1001753da49 R09: 0000000000000001 [ 77.176453] R10: 0000000000000000 R11: 1ffff1003b640f6a R12: dffffc0000000000 [ 77.183706] R13: ffffffff8148f8e1 R14: e9d44d8b0006dd9b R15: e8d44d89ffffff21 [ 77.191207] FS: 0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:00000000f7797b40 [ 77.200426] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 77.206282] CR2: 0000000020013ff8 CR3: 00000001d0a0a000 CR4: 0000000000160670 [ 77.213785] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 77.221026] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 77.228266] Stack: [ 77.230384] ffff8801db219c40 ffff8801d2a997c0 ffffed003a553405 ffffffff842bdb20 [ 77.238979] ffff8801db219c40 ffff8801db219710 ffff8801db219718 0000000000000000 [ 77.246963] 0000000000000000 ffff8801db207db0 ffffffff81d20268 ffffffff842bdb20 [ 77.254938] Call Trace: [ 77.257489] [ 77.259530] [] timerqueue_del+0x78/0x170 [ 77.265513] [] __remove_hrtimer+0x90/0x250 [ 77.271376] [] __hrtimer_run_queues+0x238/0xfe0 [ 77.277663] [] ? hrtimer_fixup_init+0x70/0x70 [ 77.283775] [] ? hrtimer_interrupt+0x131/0x440 [ 77.289975] [] hrtimer_interrupt+0x1a6/0x440 [ 77.296001] [] local_apic_timer_interrupt+0x6a/0xb0 [ 77.302637] [] smp_apic_timer_interrupt+0x76/0xa0 [ 77.309704] [] apic_timer_interrupt+0xa0/0xb0 [ 77.315816] [ 77.317854] [] ? smp_call_function_single+0x13e/0x3b0 [ 77.324952] [] ? smp_call_function_single+0x140/0x3b0 [ 77.331758] [] ? smp_call_function_single+0x13e/0x3b0 [ 77.339311] [] ? do_flush_tlb_all+0x30/0x30 [ 77.345251] [] ? generic_exec_single+0x330/0x330 [ 77.351636] [] ? do_flush_tlb_all+0x30/0x30 [ 77.357576] [] ? find_next_bit+0x3e/0x50 [ 77.363264] [] ? cpumask_next_and+0x92/0xc0 [ 77.369204] [] smp_call_function_many+0x47d/0x720 [ 77.375666] [] ? __lock_is_held+0xa1/0xf0 [ 77.381431] [] ? do_flush_tlb_all+0x30/0x30 [ 77.387803] [] native_flush_tlb_others+0xfe/0x710 [ 77.395564] [] ? _find_next_bit.part.0+0xe0/0x120 [ 77.402025] [] ? switch_mm+0x70/0x70 [ 77.407356] [] ? cpumask_any_but+0x88/0xc0 [ 77.413210] [] flush_tlb_mm_range+0x103/0x560 [ 77.419412] [] tlb_flush_mmu_tlbonly+0x185/0x2f0 [ 77.425786] [] tlb_finish_mmu+0x1b/0xa0 [ 77.431629] [] unmap_region+0x250/0x330 [ 77.437916] [] ? __vma_link_file+0x160/0x160 [ 77.443946] [] ? debug_check_no_obj_freed+0x166/0x9b0 [ 77.450753] [] ? vma_compute_subtree_gap+0x190/0x200 [ 77.457491] [] ? vma_rb_erase+0x60a/0x9f0 [ 77.463258] [] do_munmap+0x70f/0xec0 [ 77.468591] [] mmap_region+0x423/0x1250 [ 77.474187] [] ? exit_robust_list+0x240/0x240 [ 77.480301] [] ? selinux_mmap_addr+0x1f/0xf0 [ 77.486328] [] do_mmap+0x4fd/0x9d0 [ 77.491489] [] vm_mmap_pgoff+0x16e/0x1c0 [ 77.497179] [] ? vma_is_stack_for_task+0xa0/0xa0 [ 77.503553] [] ? compat_SyS_futex+0x1f9/0x2a0 [ 77.509666] [] SyS_mmap_pgoff+0xd0/0x560 [ 77.515693] [] ? vm_stat_account+0x130/0x130 [ 77.521721] [] ? do_fast_syscall_32+0xd7/0x890 [ 77.527922] [] ? vm_stat_account+0x130/0x130 [ 77.533948] [] do_fast_syscall_32+0x314/0x890 [ 77.540065] [] sysenter_flags_fixed+0xd/0x17 [ 77.546090] Code: [ 77.547850] PANIC: double fault, error_code: 0x0 [ 77.547860] CPU: 1 PID: 3476 Comm: syzkaller230323 Not tainted 4.4.113-ge70c132 #27 [ 77.547862] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 77.547865] task: ffff8801d2982f80 task.stack: ffff8801cee90000 [ 77.547867] RIP: 0010:[] [] dump_page_badflags+0x4/0x250 [ 77.547883] RSP: 0018:ffff880100000000 EFLAGS: 00010046 [ 77.547885] RAX: ffff8801d2982f80 RBX: ffffea0002d74a00 RCX: ffffffff8148f8d0 [ 77.547888] RDX: 0000000000000000 RSI: ffffffff838a8de0 RDI: ffffea0002d74a00 [ 77.547890] RBP: ffff880100000000 R08: 0000000000000001 R09: 0000000000000000 [ 77.547892] R10: 0000000000000002 R11: fffffbfff0ad7e26 R12: 0000000000000000 [ 77.547894] R13: ffffffff838a8de0 R14: 0000000000000000 R15: 0000000000000000 [ 77.547897] FS: 0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000f77b8b40 [ 77.547899] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 77.547902] CR2: ffff8800fffffff8 CR3: 00000001d0a0a000 CR4: 0000000000160670 [ 77.547907] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 77.547909] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 77.547910] Stack: [ 77.547911] [ 77.547912] Call Trace: [ 77.547914] Code: e8 82 df 06 00 e9 83 fd ff ff e8 78 df 06 00 e9 50 fd ff ff e8 6e 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 [ 77.547976] Kernel panic - not syncing: Machine halted. [ 77.701383] f5 4d 8b 76 10 49 8d 7d 08 48 89 f9 48 c1 e9 03 42 80 3c 21 00 0f 85 84 0b 00 00 4d 8b 7d 08 4d 85 ff 74 1c 4c 89 f9 48 c1 e9 03 <42> 80 3c 21 00 0f 85 44 0b 00 00 41 f6 07 01 0f 84 12 06 00 00 [ 77.727683] RIP [] rb_erase+0x626/0x1b60 [ 77.733482] RSP [ 77.737080] ---[ end trace c665561cc2d64408 ]--- [ 78.648608] Shutting down cpus with NMI [ 78.653428] Dumping ftrace buffer: [ 78.656938] (ftrace buffer empty) [ 78.660615] Kernel Offset: disabled [ 78.664209] Rebooting in 86400 seconds..