[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.739028] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [ 20.807671] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. [ 21.153608] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.349754] random: sshd: uninitialized urandom read (32 bytes read, 85 bits of entropy available) [ 22.500664] random: sshd: uninitialized urandom read (32 bytes read, 87 bits of entropy available) Warning: Permanently added '10.128.10.29' (ECDSA) to the list of known hosts. [ 27.910141] random: sshd: uninitialized urandom read (32 bytes read, 92 bits of entropy available) 2018/07/05 00:17:40 parsed 1 programs [ 29.610875] random: cc1: uninitialized urandom read (8 bytes read, 94 bits of entropy available) 2018/07/05 00:17:42 executed programs: 0 [ 30.813980] IPVS: Creating netns size=2552 id=1 [ 30.898146] IPVS: Creating netns size=2552 id=2 [ 30.969831] IPVS: Creating netns size=2552 id=3 [ 31.088376] IPVS: Creating netns size=2552 id=4 [ 31.209815] IPVS: Creating netns size=2552 id=5 [ 31.358797] IPVS: Creating netns size=2552 id=6 [ 31.495247] IPVS: Creating netns size=2552 id=7 [ 31.519963] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 31.580175] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 31.711454] IPVS: Creating netns size=2552 id=8 [ 31.820782] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 31.887783] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 31.958063] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.020615] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.131389] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.226144] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.362795] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.429713] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.439637] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.462669] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 32.528552] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.564165] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 32.624543] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.662889] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 32.673138] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.708775] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.724013] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 32.735152] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.876748] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 32.948770] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.987640] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.998569] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.016911] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.094557] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.131450] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.180812] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.189919] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.235746] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.281558] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.291282] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.338999] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.385412] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.396129] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.458552] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.522739] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.530652] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.549287] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.559723] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.571979] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.623979] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.672735] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.690669] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.771619] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.835426] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.885807] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.896714] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.969900] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.979796] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.990665] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 34.057200] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.067706] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 34.177617] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.269438] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.317542] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.346889] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.412182] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.460657] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.519913] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.529533] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.591860] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.622448] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.687308] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 37.193774] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.468956] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.659919] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.869741] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.988109] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.208691] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.406160] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.612085] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.636848] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.718890] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.805666] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.933383] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.973001] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 39.086762] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 39.225053] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 39.295688] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 39.436271] ================================================================== [ 39.443799] BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 [ 39.451070] Read of size 4 at addr ffff8801d2feca00 by task syz-executor3/6372 [ 39.458444] [ 39.460071] CPU: 0 PID: 6372 Comm: syz-executor3 Not tainted 4.4.139-g7ba5557 #1 [ 39.467587] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 39.476927] 0000000000000000 b74636d0dd7f6a82 ffff8801d2b6fc78 ffffffff81e0d58d [ 39.484985] ffffea00074bfb00 ffff8801d2feca00 0000000000000000 ffff8801d2feca00 [ 39.493022] ffffffff82f19100 ffff8801d2b6fcb0 ffffffff81515a16 ffff8801d2feca00 [ 39.501063] Call Trace: [ 39.503642] [] dump_stack+0xc1/0x124 [ 39.509012] [] ? sock_release+0x1c0/0x1c0 [ 39.514803] [] print_address_description+0x6c/0x216 [ 39.521469] [] ? sock_release+0x1c0/0x1c0 [ 39.527445] [] kasan_report.cold.7+0x175/0x2f7 [ 39.533683] [] ? l2tp_session_queue_purge+0xf4/0x100 [ 39.540433] [] __asan_report_load4_noabort+0x14/0x20 [ 39.547199] [] l2tp_session_queue_purge+0xf4/0x100 [ 39.553777] [] ? sock_release+0x1c0/0x1c0 [ 39.559570] [] pppol2tp_release+0x1ff/0x310 [ 39.565535] [] sock_release+0x96/0x1c0 [ 39.571063] [] sock_close+0x16/0x20 [ 39.576333] [] __fput+0x235/0x6f0 [ 39.581430] [] ____fput+0x15/0x20 [ 39.586528] [] task_work_run+0x10f/0x190 [ 39.592232] [] exit_to_usermode_loop+0x13d/0x160 [ 39.598805] [] do_fast_syscall_32+0x620/0x8b0 [ 39.604946] [] sysenter_flags_fixed+0xd/0x17 [ 39.610987] [ 39.612604] Allocated by task 6339: [ 39.616239] [] save_stack_trace+0x26/0x50 [ 39.622161] [] save_stack+0x43/0xd0 [ 39.627556] [] kasan_kmalloc+0xc7/0xe0 [ 39.633236] [] __kmalloc+0x124/0x310 [ 39.638735] [] l2tp_session_create+0x39/0x1030 [ 39.645091] [] pppol2tp_connect+0x10f0/0x1910 [ 39.651364] [] SYSC_connect+0x1b8/0x300 [ 39.657111] [] SyS_connect+0x24/0x30 [ 39.662608] [] do_fast_syscall_32+0x326/0x8b0 [ 39.668874] [] sysenter_flags_fixed+0xd/0x17 [ 39.675053] [ 39.676707] Freed by task 6339: [ 39.679968] [] save_stack_trace+0x26/0x50 [ 39.685886] [] save_stack+0x43/0xd0 [ 39.691299] [] kasan_slab_free+0x72/0xc0 [ 39.697135] [] kfree+0xf4/0x310 [ 39.702185] [] l2tp_session_free+0x170/0x200 [ 39.708362] [] l2tp_tunnel_closeall+0x2b9/0x350 [ 39.714800] [] l2tp_udp_encap_destroy+0x8b/0xf0 [ 39.721235] [] udpv6_destroy_sock+0xb1/0xd0 [ 39.727327] [] sk_common_release+0x6d/0x300 [ 39.733427] [] udp_lib_close+0x15/0x20 [ 39.739084] [] inet_release+0xff/0x1d0 [ 39.744780] [] inet6_release+0x50/0x70 [ 39.750460] [] sock_release+0x96/0x1c0 [ 39.756114] [] sock_close+0x16/0x20 [ 39.761517] [] __fput+0x235/0x6f0 [ 39.766747] [] ____fput+0x15/0x20 [ 39.771969] [] task_work_run+0x10f/0x190 [ 39.777803] [] exit_to_usermode_loop+0x13d/0x160 [ 39.784333] [] do_fast_syscall_32+0x620/0x8b0 [ 39.790601] [] sysenter_flags_fixed+0xd/0x17 [ 39.796781] [ 39.798397] The buggy address belongs to the object at ffff8801d2feca00 [ 39.798397] which belongs to the cache kmalloc-512 of size 512 [ 39.811045] The buggy address is located 0 bytes inside of [ 39.811045] 512-byte region [ffff8801d2feca00, ffff8801d2fecc00) [ 39.822737] The buggy address belongs to the page: [ 39.830316] BUG: unable to handle kernel paging request at fffff24000e97fec [ SeaBIOS (version 1.8.2-20171130_102032-google) Total RAM Size = 0x00000001e0000000 = 7680 MiB CPUs found: 2 Max CPUs supported: 256 found virtio-scsi at 0:3 virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0 virtio-scsi blksize=512 sectors=4194304 = 2048 MiB drive 0x000f2290: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304 Booting from Hard Disk 0... early console in decompress_kernel input_data: 0x0000000003b5226e input_len: 0x00000000014cb327 output: 0x0000000001000000 output_len: 0x0000000004008a40 run_size: 0x0000000005752000 Decompressing Linux... Parsing ELF... done. Booting the kernel. [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Initializing cgroup subsys cpuacct [ 0.000000] Initializing cgroup subsys schedtune [ 0.000000] Linux version 4.4.139-g7ba5557 (syzkaller@ci) (gcc version 8.0.1 20180413 (experimental) (GCC) ) #1 SMP PREEMPT Tue Jul 3 16:40:40 UTC 2018 [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz root=/dev/sda1 console=ttyS0 earlyprintk=serial vsyscall=native rodata=n ftrace_dump_on_oops=orig_cpu oops=panic panic_on_warn=1 nmi_watchdog=panic panic=86400 nopti [ 0.000000] KERNEL supported cpus: [ 0.000000] Intel GenuineIntel [ 0.000000] AMD AuthenticAMD [ 0.000000] Centaur CentaurHauls [ 0.000000] x86/fpu: xstate_offset[2]: 576, xstate_sizes[2]: 256 [ 0.000000] x86/fpu: Supporting XSAVE feature 0x01: 'x87 floating point registers' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x02: 'SSE registers' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x04: 'AVX registers' [ 0.000000] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'standard' format. [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000bfff2fff] usable [ 0.000000] BIOS-e820: [mem 0x00000000bfff3000-0x00000000bfffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fffbc000-0x00000000ffffffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000021fffffff] usable [ 0.000000] bootconsole [earlyser0] enabled [ 0.000000] NX (Execute Disable) protection: active [ 0.000000] SMBIOS 2.4 present. [ 0.000000] Hypervisor detected: KVM [ 0.000000] Kernel/User page tables isolation: disabled [ 0.000000] e820: last_pfn = 0x220000 max_arch_pfn = 0x400000000 [ 0.000000] x86/PAT: Configuration [0-7]: WB WC UC- UC WB WC UC- WT [ 0.000000] e820: last_pfn = 0xbfff3 max_arch_pfn = 0x400000000 [ 0.000000] found SMP MP-table at [mem 0x000f2310-0x000f231f] mapped at [ffff8800000f2310] [ 0.000000] Scanning 1 areas for low memory corruption [ 0.000000] Using GB pages for direct mapping [ 0.000000] ACPI: Early table checksum verification disabled [ 0.000000] ACPI: RSDP 0x00000000000F22D0 000014 (v00 Google) [ 0.000000] ACPI: RSDT 0x00000000BFFF3430 000038 (v01 Google GOOGRSDT 00000001 GOOG 00000001) [ 0.000000] ACPI: FACP 0x00000000BFFFCF60 0000F4 (v02 Google GOOGFACP 00000001 GOOG 00000001) [ 0.000000] ACPI: DSDT 0x00000000BFFF3470 0017B2 (v01 Google GOOGDSDT 00000001 GOOG 00000001) [ 0.000000] ACPI: FACS 0x00000000BFFFCF00 000040 [ 0.000000] ACPI: FACS 0x00000000BFFFCF00 000040 [ 0.000000] ACPI: SSDT 0x00000000BFFF65F0 00690D (v01 Google GOOGSSDT 00000001 GOOG 00000001) [ 0.000000] ACPI: APIC 0x00000000BFFF5D10 000076 (v01 Google GOOGAPIC 00000001 GOOG 00000001) [ 0.000000] ACPI: WAET 0x00000000BFFF5CE0 000028 (v01 Google GOOGWAET 00000001 GOOG 00000001) [ 0.000000] ACPI: SRAT 0x00000000BFFF4C30 0000C8 (v01 Google GOOGSRAT 00000001 GOOG 00000001) [ 0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00 [ 0.000000] kvm-clock: cpu 0, msr 2:1fffd001, primary cpu clock [ 0.000000] kvm-clock: using sched offset of 2556303500 cycles [ 0.000000] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns [ 0.000000] Zone ranges: [ 0.000000] DMA [mem 0x0000000000001000-0x0000000000ffffff] [ 0.000000] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] [ 0.000000] Normal [mem 0x0000000100000000-0x000000021fffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000000001000-0x000000000009efff] [ 0.000000] node 0: [mem 0x0000000000100000-0x00000000bfff2fff] [ 0.000000] node 0: [mem 0x0000000100000000-0x000000021fffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000000001000-0x000000021fffffff]