[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.643016] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.120079] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 25.587182] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 26.717705] random: sshd: uninitialized urandom read (32 bytes read, 113 bits of entropy available) [ 37.447047] random: sshd: uninitialized urandom read (32 bytes read, 122 bits of entropy available) Warning: Permanently added '10.128.0.51' (ECDSA) to the list of known hosts. [ 42.833165] random: sshd: uninitialized urandom read (32 bytes read, 124 bits of entropy available) 2018/04/27 00:02:44 parsed 1 programs 2018/04/27 00:02:44 executed programs: 0 [ 43.274267] IPVS: Creating netns size=2552 id=1 [ 43.327810] IPVS: Creating netns size=2552 id=2 [ 43.379695] IPVS: Creating netns size=2552 id=3 [ 43.425773] IPVS: Creating netns size=2552 id=4 [ 43.494074] IPVS: Creating netns size=2552 id=5 [ 43.543047] IPVS: Creating netns size=2552 id=6 [ 43.595701] l2tp_core: tunl 4: sockfd_lookup(fd=10) returned -9 [ 43.606043] IPVS: Creating netns size=2552 id=7 [ 43.652754] l2tp_core: tunl 4: sockfd_lookup(fd=9) returned -9 [ 43.684231] IPVS: Creating netns size=2552 id=8 [ 43.728198] l2tp_core: tunl 4: sockfd_lookup(fd=9) returned -9 [ 44.045595] l2tp_core: tunl 4: sockfd_lookup(fd=9) returned -9 [ 44.281320] l2tp_core: tunl 4: sockfd_lookup(fd=9) returned -9 [ 44.666841] l2tp_core: tunl 4: sockfd_lookup(fd=9) returned -9 [ 45.156034] l2tp_core: tunl 4: sockfd_lookup(fd=9) returned -9 [ 45.179638] ================================================================== [ 45.187058] BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 [ 45.194684] Read of size 4 at addr ffff8800b7bc7400 by task syz-executor5/4219 [ 45.202026] [ 45.203649] CPU: 1 PID: 4219 Comm: syz-executor5 Not tainted 4.4.128-gbd23e3a #19 [ 45.211248] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.220586] 0000000000000000 21b6534370252da7 ffff8801d6787c78 ffffffff81e0daad [ 45.228598] ffffea0002def180 ffff8800b7bc7400 0000000000000000 ffff8800b7bc7400 [ 45.236603] ffffffff82f17b20 ffff8801d6787cb0 ffffffff815150ac ffff8800b7bc7400 [ 45.244589] Call Trace: [ 45.247157] [] dump_stack+0xc1/0x124 [ 45.252498] [] ? sock_release+0x1c0/0x1c0 [ 45.258279] [] print_address_description+0x6c/0x216 [ 45.264935] [] ? sock_release+0x1c0/0x1c0 [ 45.270732] [] kasan_report.cold.7+0x175/0x2f7 [ 45.276958] [] ? l2tp_session_queue_purge+0xf4/0x100 [ 45.283704] [] __asan_report_load4_noabort+0x14/0x20 [ 45.290457] [] l2tp_session_queue_purge+0xf4/0x100 [ 45.297033] [] ? sock_release+0x1c0/0x1c0 [ 45.302825] [] pppol2tp_release+0x1ff/0x310 [ 45.308785] [] sock_release+0x96/0x1c0 [ 45.314318] [] sock_close+0x16/0x20 [ 45.319597] [] __fput+0x235/0x6f0 [ 45.324691] [] ____fput+0x15/0x20 [ 45.329787] [] task_work_run+0x10f/0x190 [ 45.335488] [] exit_to_usermode_loop+0x13d/0x160 [ 45.342295] [] do_fast_syscall_32+0x620/0x8b0 [ 45.348451] [] sysenter_flags_fixed+0xd/0x17 [ 45.354489] [ 45.356101] Allocated by task 4219: [ 45.359711] [] save_stack_trace+0x26/0x50 [ 45.365628] [] save_stack+0x43/0xd0 [ 45.371027] [] kasan_kmalloc+0xc7/0xe0 [ 45.376688] [] __kmalloc+0x124/0x310 [ 45.382169] [] l2tp_session_create+0x39/0x1030 [ 45.388517] [] pppol2tp_connect+0x1095/0x18a0 [ 45.394791] [] SYSC_connect+0x1b8/0x300 [ 45.400538] [] SyS_connect+0x24/0x30 [ 45.406016] [] do_fast_syscall_32+0x326/0x8b0 [ 45.412278] [] sysenter_flags_fixed+0xd/0x17 [ 45.418451] [ 45.420059] Freed by task 4235: [ 45.423324] [] save_stack_trace+0x26/0x50 [ 45.429250] [] save_stack+0x43/0xd0 [ 45.434647] [] kasan_slab_free+0x72/0xc0 [ 45.440485] [] kfree+0xf4/0x310 [ 45.445553] [] l2tp_session_free+0x170/0x200 [ 45.451737] [] l2tp_tunnel_closeall+0x2b9/0x350 [ 45.458170] [] l2tp_udp_encap_destroy+0x8b/0xf0 [ 45.464593] [] udpv6_destroy_sock+0xb1/0xd0 [ 45.470671] [] sk_common_release+0x6d/0x300 [ 45.476740] [] udp_lib_close+0x15/0x20 [ 45.482389] [] inet_release+0xff/0x1d0 [ 45.488028] [] inet6_release+0x50/0x70 [ 45.493670] [] sock_release+0x96/0x1c0 [ 45.499308] [] sock_close+0x16/0x20 [ 45.504688] [] __fput+0x235/0x6f0 [ 45.509902] [] ____fput+0x15/0x20 [ 45.515124] [] task_work_run+0x10f/0x190 [ 45.520938] [] exit_to_usermode_loop+0x13d/0x160 [ 45.527462] [] do_fast_syscall_32+0x620/0x8b0 [ 45.533709] [] sysenter_flags_fixed+0xd/0x17 [ 45.539872] [ 45.541477] The buggy address belongs to the object at ffff8800b7bc7400 [ 45.541477] which belongs to the cache kmalloc-512 of size 512 [ 45.554120] The buggy address is located 0 bytes inside of [ 45.554120] 512-byte region [ffff8800b7bc7400, ffff8800b7bc7600) [ 45.565804] The buggy address belongs to the page: [ 45.570855] kasan: CONFIG_KASAN_INLINE enabled [ 45.575268] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASeaBIOS (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 0x000f2350: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304 Booting from Hard Disk 0... early console in decompress_kernel input_data: 0x0000000003b5326e input_len: 0x00000000014ca885 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 4.4.128-gbd23e3a (syzkaller@ci) (gcc version 8.0.1 20180413 (experimental) (GCC) ) #19 SMP PREEMPT Tue Apr 24 03:38:36 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 workqueue.watchdog_thresh=120 [ 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] x86/fpu: Using 'eager' FPU context switches. [ 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] 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 0x000f23d0-0x000f23df] mapped at [ffff8800000f23d0] [ 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 0x00000000000F2390 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 2306299210 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] [ 0.000000] kasan: KernelAddressSanitizer initialized [ 0.000000] ACPI: PM-Timer IO Port: 0xb008 [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1]) [ 0.000000] IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23 [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 5 global_irq 5 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level) [ 0.000000] Using ACPI (MADT) for SMP configuration information [ 0.000000] smpboot: Allowing 2 CPUs, 0 hotplug CPUs [ 0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff] [ 0.000000] PM: Registered nosave memory: [mem 0x0009f000-0x0009ffff] [ 0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000effff] [ 0.000000] PM: Registered nosave memory: [mem 0x000f0000-0x000fffff] [ 0.000000] PM: Registered nosave memory: [mem 0xbfff3000-0xbfffffff] [ 0.000000] PM: Registered nosave memory: [mem 0xc0000000-0xfffbbfff] [ 0.000000] PM: Registered nosave memory: [mem 0xfffbc000-0xffffffff] [ 0.000000] e820: [mem 0xc0000000-0xfffbbfff] available for PCI devices [ 0.000000] Booting paravirtualized kernel on KVM [ 0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [ 0.000000] setup_percpu: NR_CPUS:64 nr_cpumask_bits:64 nr_cpu_ids:2 nr_node_ids:1 [ 0.000000] PERCPU: Embedded 42 pages/cpu @ffff8801db200000 s134024 r8192 d29816 u1048576 [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 1935227 [ 0.000000] Kernel 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 workqueue.watchdog_thresh=120 [ 0.000000] PID hash table entries: 4096 (order: 3, 32768 bytes) [ 0.000000] Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes) [ 0.000000] Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes) [ 0.000000] Memory: 6579092K/7863876K available (41745K kernel code, 6300K rwdata, 9048K rodata, 1864K init, 23696K bss, 1284784K reserved, 0K cma-reserved) [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1 [ 0.000000] Kernel/User page tables isolation: enabled [ 0.000000] Running RCU self tests [ 0.000000] Preemptible hierarchical RCU implementation. [ 0.000000] RCU lockdep checking is enabled. [ 0.000000] Build-time adjustment of leaf fanout to 64. [ 0.000000] RCU restricting CPUs from NR_CPUS=64 to nr_cpu_ids=2. [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=2 [ 0.000000] NR_IRQS:4352 nr_irqs:440 16 [ 0.000000] console [ttyS0] enabled [ 0.000000] console [ttyS0] enabled [ 0.000000] bootconsole [earlyser0] disabled [ 0.000000] bootconsole [earlyser0] disabled [ 0.000000] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar [ 0.000000] ... MAX_LOCKDEP_SUBCLASSES: 8 [ 0.000000] ... MAX_LOCK_DEPTH: 48 [ 0.000000] ... MAX_LOCKDEP_KEYS: 8191 [ 0.000000] ... CLASSHASH_SIZE: 4096 [ 0.000000] ... MAX_LOCKDEP_ENTRIES: 32768 [ 0.000000] ... MAX_LOCKDEP_CHAINS: 65536 [ 0.000000] ... CHAINHASH_SIZE: 32768 [ 0.000000] memory used by lock dependency info: 8159 kB [ 0.000000] per task-struct memory footprint: 1920 bytes [ 0.000000] tsc: Detected 2300.000 MHz processor [ 1.461775] Calibrating delay loop (skipped) preset value.. 4600.00 BogoMIPS (lpj=23000000) [ 1.463011] pid_max: default: 32768 minimum: 301 [ 1.463734] ACPI: Core revision 20150930 [ 1.876294] ACPI: 2 ACPI AML tables successfully acquired and loaded [ 1.878345] Security Framework initialized [ 1.878980] SELinux: Initializing. [ 1.879667] AppArmor: AppArmor disabled by boot time parameter [ 1.880654] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.881851] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.885560] Initializing cgroup subsys io [ 1.886233] Initializing cgroup subsys freezer [ 1.886880] Initializing cgroup subsys hugetlb [ 1.887578] Initializing cgroup subsys debug [ 1.888348] CPU: Physical Processor ID: 0 [ 1.890090] mce: CPU supports 32 MCE banks [ 1.890860] Last level iTLB entries: 4KB 1024, 2MB 1024, 4MB 1024 [ 1.891787] Last level dTLB entries: 4KB 1024, 2MB 1024, 4MB 1024, 1GB 4 [ 1.892775] Spectre V2 : Mitigation: Full generic retpoline [ 1.896006] Freeing SMP alternatives memory: 48K [ 1.905569] ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1 [ 2.021065] smpboot: CPU0: Intel(R) Xeon(R) CPU @ 2.30GHz (family: 0x6, model: 0x3f, stepping: 0x0) [ 2.022588] Performance Events: unsupported p6 CPU model 63 no PMU driver, software events only. [ 2.111402] x86: Booting SMP configuration: [ 2.112402] .... node #0, CPUs: #1 [ 2.113222] kvm-clock: cpu 1, msr 2:1fffd041, secondary cpu clock [ 2.118236] x86: Booted up 1 node, 2 CPUs [ 2.118845] smpboot: Total of 2 processors activated (9200.00 BogoMIPS) [ 2.123874] devtmpfs: initialized [ 2.134393] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [ 2.135817] futex hash table entries: 512 (order: 4, 65536 bytes) [ 2.137535] xor: automatically using best checksumming function: [ 2.142407] kworker/u4:0 (21) used greatest stack depth: 27920 bytes left [ 2.231081] avx : 21838.400 MB/sec [ 2.232296] RTC time: 0:02:51, date: 04/27/18 [ 2.234782] NET: Registered protocol family 16 [ 2.235928] schedtune: init normalization constants... [ 2.236682] schedtune: no energy model data [ 2.237277] schedtune: disabled! [ 2.271297] cpuidle: using governor ladder [ 2.301125] cpuidle: using governor menu [ 2.302455] ACPI: bus type PCI registered [ 2.303070] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 [ 2.306175] PCI: Using configuration type 1 for base access [ 2.317876] kworker/u4:1 (49) used greatest stack depth: 27424 bytes left [ 2.449249] kworker/u4:2 (279) used greatest stack depth: 27024 bytes left [ 2.790996] raid6: sse2x1 gen() 4619 MB/s [ 2.960978] raid6: sse2x1 xor() 2599 MB/s [ 3.130955] raid6: sse2x2 gen() 7026 MB/s [ 3.300939] raid6: sse2x2 xor() 4057 MB/s [ 3.470922] raid6: sse2x4 gen() 8690 MB/s [ 3.640908] raid6: sse2x4 xor() 5308 MB/s [ 3.810880] raid6: avx2x1 gen() 9144 MB/s [ 3.980864] raid6: avx2x2 gen() 14376 MB/s [ 4.150843] raid6: avx2x4 gen() 19019 MB/s [ 4.151584] raid6: using algorithm avx2x4 gen() 19019 MB/s [ 4.152424] raid6: using avx2x2 recovery algorithm [ 4.153815] ACPI: Added _OSI(Module Device) [ 4.154474] ACPI: Added _OSI(Processor Device) [ 4.155115] ACPI: Added _OSI(3.0 _SCP Extensions) [ 4.155801] ACPI: Added _OSI(Processor Aggregator Device) [ 4.183107] ACPI: Executed 2 blocks of module-level executable AML code [ 5.145696] ACPI: Interpreter enabled [ 5.147045] ACPI: (supports S0 S3 S4 S5) [ 5.147623] ACPI: Using IOAPIC for interrupt routing [ 5.149101] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug [ 6.446086] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) [ 6.447170] acpi PNP0A03:00: _OSC: OS supports [ASPM ClockPM Segments MSI] [ 6.448651] acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM [ 6.449704] acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended PCI configuration space under this bridge. [ 6.479563] PCI host bridge to bus 0000:00 [ 6.480304] pci_bus 0000:00: root bus resource [io 0x0000-0x0cf7 window] [ 6.481344] pci_bus 0000:00: root bus resource [io 0x0d00-0xffff window] [ 6.482331] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff window] [ 6.483439] pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window] [ 6.484571] pci_bus 0000:00: root bus resource [bus 00-ff] [ 6.529895] pci 0000:00:01.3: quirk: [io 0xb000-0xb03f] claimed by PIIX4 ACPI [ 6.625521] ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11) [ 6.632708] ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11) [ 6.639650] ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11) [ 6.646239] ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11) [ 6.650223] ACPI: PCI Interrupt Link [LNKS] (IRQs *9)