[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.251737] 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: [ 24.180182] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 24.465722] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 25.629857] random: sshd: uninitialized urandom read (32 bytes read, 120 bits of entropy available) [ 25.801697] random: sshd: uninitialized urandom read (32 bytes read, 122 bits of entropy available) Warning: Permanently added '10.128.10.36' (ECDSA) to the list of known hosts. [ 31.208337] random: nonblocking pool is initialized executing program [ 31.358810] ================================================================== [ 31.366191] BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 [ 31.373436] Read of size 4 at addr ffff8800b57b6f00 by task syz-executor928/3809 [ 31.380938] [ 31.382538] CPU: 0 PID: 3809 Comm: syz-executor928 Not tainted 4.4.139-g7ba5557 #66 [ 31.390387] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.399712] 0000000000000000 fd6b441d967eb3f5 ffff8800ae29fcc0 ffffffff81e0d58d [ 31.407711] ffffea0002d5ed80 ffff8800b57b6f00 0000000000000000 ffff8800b57b6f00 [ 31.415688] ffffffff82f19100 ffff8800ae29fcf8 ffffffff81515a16 ffff8800b57b6f00 [ 31.423674] Call Trace: [ 31.426245] [] dump_stack+0xc1/0x124 [ 31.431581] [] ? sock_release+0x1c0/0x1c0 [ 31.437365] [] print_address_description+0x6c/0x216 [ 31.444002] [] ? sock_release+0x1c0/0x1c0 [ 31.449776] [] kasan_report.cold.7+0x175/0x2f7 [ 31.455987] [] ? l2tp_session_queue_purge+0xf4/0x100 [ 31.462712] [] __asan_report_load4_noabort+0x14/0x20 [ 31.469445] [] l2tp_session_queue_purge+0xf4/0x100 [ 31.475994] [] ? sock_release+0x1c0/0x1c0 [ 31.481764] [] pppol2tp_release+0x1ff/0x310 [ 31.487713] [] sock_release+0x96/0x1c0 [ 31.493221] [] sock_close+0x16/0x20 [ 31.498482] [] __fput+0x235/0x6f0 [ 31.503566] [] ____fput+0x15/0x20 [ 31.508661] [] task_work_run+0x10f/0x190 [ 31.514351] [] exit_to_usermode_loop+0x13d/0x160 [ 31.520727] [] syscall_return_slowpath+0x1b5/0x1f0 [ 31.527279] [] int_ret_from_sys_call+0x25/0xa3 [ 31.533477] [ 31.535084] Allocated by task 3808: [ 31.538680] [] save_stack_trace+0x26/0x50 [ 31.544578] [] save_stack+0x43/0xd0 [ 31.549955] [] kasan_kmalloc+0xc7/0xe0 [ 31.555587] [] __kmalloc+0x124/0x310 [ 31.561037] [] l2tp_session_create+0x39/0x1030 [ 31.567360] [] pppol2tp_connect+0x10f0/0x1910 [ 31.573603] [] SYSC_connect+0x1b8/0x300 [ 31.579319] [] SyS_connect+0x24/0x30 [ 31.584776] [] entry_SYSCALL_64_fastpath+0x22/0x9e [ 31.591446] [ 31.593044] Freed by task 3808: [ 31.596290] [] save_stack_trace+0x26/0x50 [ 31.602179] [] save_stack+0x43/0xd0 [ 31.607551] [] kasan_slab_free+0x72/0xc0 [ 31.613356] [] kfree+0xf4/0x310 [ 31.618371] [] l2tp_session_free+0x170/0x200 [ 31.624528] [] l2tp_tunnel_closeall+0x2b9/0x350 [ 31.630941] [] l2tp_udp_encap_destroy+0x8b/0xf0 [ 31.637360] [] udp_destroy_sock+0x118/0x1a0 [ 31.643436] [] sk_common_release+0x6d/0x300 [ 31.649496] [] udp_lib_close+0x15/0x20 [ 31.655138] [] inet_release+0xff/0x1d0 [ 31.660763] [] sock_release+0x96/0x1c0 [ 31.666389] [] sock_close+0x16/0x20 [ 31.671758] [] __fput+0x235/0x6f0 [ 31.676951] [] ____fput+0x15/0x20 [ 31.682147] [] task_work_run+0x10f/0x190 [ 31.687974] [] exit_to_usermode_loop+0x13d/0x160 [ 31.694467] [] syscall_return_slowpath+0x1b5/0x1f0 [ 31.701138] [] int_ret_from_sys_call+0x25/0xa3 [ 31.707471] [ 31.709072] The buggy address belongs to the object at ffff8800b57b6f00 [ 31.709072] which belongs to the cache kmalloc-512 of size 512 [ 31.721707] The buggy address is located 0 bytes inside of [ 31.721707] 512-byte region [ffff8800b57b6f00, ffff8800b57b7100) [ 31.733376] The buggy address belongs to the page: 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: 0x00000000014cb386 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) ) #66 SMP PREEMPT Thu Jul 5 16:35:51 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=140 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 2164804394 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=140 nopti [ 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 (41757K kernel code, 6301K 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] 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 [ 1.217117] Calibrating delay loop (skipped) preset value.. 4600.00 BogoMIPS (lpj=23000000) [ 1.218271] pid_max: default: 32768 minimum: 301 [ 1.218991] ACPI: Core revision 20150930 [ 1.612676] ACPI: 2 ACPI AML tables successfully acquired and loaded [ 1.614007] Security Framework initialized [ 1.614638] SELinux: Initializing. [ 1.615384] AppArmor: AppArmor disabled by boot time parameter [ 1.616335] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.617390] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.621002] Initializing cgroup subsys io [ 1.621637] Initializing cgroup subsys freezer [ 1.622284] Initializing cgroup subsys hugetlb [ 1.622935] Initializing cgroup subsys debug [ 1.623733] CPU: Physical Processor ID: 0 [ 1.625737] mce: CPU supports 32 MCE banks [ 1.626610] Last level iTLB entries: 4KB 1024, 2MB 1024, 4MB 1024 [ 1.627497] Last level dTLB entries: 4KB 1024, 2MB 1024, 4MB 1024, 1GB 4 [ 1.628433] Spectre V2 : Mitigation: Full generic retpoline [ 1.631521] Freeing SMP alternatives memory: 48K [ 1.641020] ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1 [ 1.756425] smpboot: CPU0: Intel(R) Xeon(R) CPU @ 2.30GHz (family: 0x6, model: 0x3f, stepping: 0x0) [ 1.757988] Performance Events: unsupported p6 CPU model 63 no PMU driver, software events only. [ 1.846740] x86: Booting SMP configuration: [ 1.847501] .... node #0, CPUs: #1 [ 1.848314] kvm-clock: cpu 1, msr 2:1fffd041, secondary cpu clock [ 1.853121] x86: Booted up 1 node, 2 CPUs [ 1.853818] smpboot: Total of 2 processors activated (9200.00 BogoMIPS) [ 1.858197] devtmpfs: initialized [ 1.868093] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [ 1.869737] futex hash table entries: 512 (order: 4, 65536 bytes) [ 1.871513] xor: automatically using best checksumming function: [ 1.884012] kworker/u4:0 (21) used greatest stack depth: 27920 bytes left [ 1.966435] avx : 23508.000 MB/sec [ 1.967830] RTC time: 23:56:09, date: 07/05/18 [ 1.971035] NET: Registered protocol family 16 [ 1.972277] schedtune: init normalization constants... [ 1.973087] schedtune: no energy model data [ 1.973664] schedtune: disabled! [ 2.006688] cpuidle: using governor ladder [ 2.036494] cpuidle: using governor menu [ 2.037888] ACPI: bus type PCI registered [ 2.038526] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 [ 2.041184] PCI: Using configuration type 1 for base access [ 2.045647] kworker/u4:0 (39) used greatest stack depth: 27616 bytes left [ 2.048466] kworker/u4:1 (52) used greatest stack depth: 27424 bytes left [ 2.406406] raid6: sse2x1 gen() 4630 MB/s [ 2.576382] raid6: sse2x1 xor() 2601 MB/s [ 2.746364] raid6: sse2x2 gen() 7019 MB/s [ 2.916353] raid6: sse2x2 xor() 4026 MB/s [ 3.086329] raid6: sse2x4 gen() 8739 MB/s [ 3.256320] raid6: sse2x4 xor() 5350 MB/s [ 3.426305] raid6: avx2x1 gen() 9400 MB/s [ 3.596287] raid6: avx2x2 gen() 14680 MB/s [ 3.766275] raid6: avx2x4 gen() 19255 MB/s [ 3.766928] raid6: using algorithm avx2x4 gen() 19255 MB/s [ 3.767674] raid6: using avx2x2 recovery algorithm [ 3.768927] ACPI: Added _OSI(Module Device) [ 3.769543] ACPI: Added _OSI(Processor Device) [ 3.770187] ACPI: Added _OSI(3.0 _SCP Extensions) [ 3.770864] ACPI: Added _OSI(Processor Aggregator Device) [ 3.797229] ACPI: Executed 2 blocks of module-level executable AML code [ 4.687024] ACPI: Interpreter enabled [ 4.688068] ACPI: (supports S0 S3 S4 S5) [ 4.688629] ACPI: Using IOAPIC for interrupt routing [ 4.689783] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug