IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready ================================================================== BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830 Read of size 4 at addr ffff8801d2feca00 by task syz-executor3/6372 CPU: 0 PID: 6372 Comm: syz-executor3 Not tainted 4.4.139-g7ba5557 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 b74636d0dd7f6a82 ffff8801d2b6fc78 ffffffff81e0d58d ffffea00074bfb00 ffff8801d2feca00 0000000000000000 ffff8801d2feca00 ffffffff82f19100 ffff8801d2b6fcb0 ffffffff81515a16 ffff8801d2feca00 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 [] print_address_description+0x6c/0x216 mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408 [] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428 [] l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830 [] pppol2tp_release+0x1ff/0x310 net/l2tp/l2tp_ppp.c:509 [] sock_release+0x96/0x1c0 net/socket.c:586 [] sock_close+0x16/0x20 net/socket.c:1037 [] __fput+0x235/0x6f0 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10f/0x190 kernel/task_work.c:115 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:252 [] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:348 [inline] [] do_syscall_32_irqs_on arch/x86/entry/common.c:398 [inline] [] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 Allocated by task 6339: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616 [] __kmalloc+0x124/0x310 mm/slub.c:3613 [] kmalloc include/linux/slab.h:481 [inline] [] kzalloc include/linux/slab.h:620 [inline] [] l2tp_session_create+0x39/0x1030 net/l2tp/l2tp_core.c:1748 [] pppol2tp_connect+0x10f0/0x1910 net/l2tp/l2tp_ppp.c:725 [] SYSC_connect+0x1b8/0x300 net/socket.c:1557 [] SyS_connect+0x24/0x30 net/socket.c:1538 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 Freed by task 6339: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack+0x43/0xd0 mm/kasan/kasan.c:512 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589 [] slab_free_hook mm/slub.c:1383 [inline] [] slab_free_freelist_hook mm/slub.c:1405 [inline] [] slab_free mm/slub.c:2859 [inline] [] kfree+0xf4/0x310 mm/slub.c:3749 [] l2tp_session_free+0x170/0x200 net/l2tp/l2tp_core.c:1676 [] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:293 [inline] [] l2tp_tunnel_closeall+0x2b9/0x350 net/l2tp/l2tp_core.c:1279 [] l2tp_udp_encap_destroy+0x8b/0xf0 net/l2tp/l2tp_core.c:1300 [] udpv6_destroy_sock+0xb1/0xd0 net/ipv6/udp.c:1421 [] sk_common_release+0x6d/0x300 net/core/sock.c:2680 [] udp_lib_close+0x15/0x20 include/net/udp.h:190 [] inet_release+0xff/0x1d0 net/ipv4/af_inet.c:435 [] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:424 [] sock_release+0x96/0x1c0 net/socket.c:586 [] sock_close+0x16/0x20 net/socket.c:1037 [] __fput+0x235/0x6f0 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10f/0x190 kernel/task_work.c:115 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:252 [] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:348 [inline] [] do_syscall_32_irqs_on arch/x86/entry/common.c:398 [inline] [] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 The buggy address belongs to the object at ffff8801d2feca00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes inside of 512-byte region [ffff8801d2feca00, ffff8801d2fecc00) The buggy address belongs to the page: BUG: unable to handle kernel paging request at fffff24000e97fec Initializing cgroup subsys cpuset Initializing cgroup subsys cpu Initializing cgroup subsys cpuacct Initializing cgroup subsys schedtune 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 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 KERNEL supported cpus: Intel GenuineIntel AMD AuthenticAMD Centaur CentaurHauls x86/fpu: xstate_offset[2]: 576, xstate_sizes[2]: 256 x86/fpu: Supporting XSAVE feature 0x01: 'x87 floating point registers' x86/fpu: Supporting XSAVE feature 0x02: 'SSE registers' x86/fpu: Supporting XSAVE feature 0x04: 'AVX registers' x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'standard' format. e820: BIOS-provided physical RAM map: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved BIOS-e820: [mem 0x0000000000100000-0x00000000bfff2fff] usable BIOS-e820: [mem 0x00000000bfff3000-0x00000000bfffffff] reserved BIOS-e820: [mem 0x00000000fffbc000-0x00000000ffffffff] reserved BIOS-e820: [mem 0x0000000100000000-0x000000021fffffff] usable bootconsole [earlyser0] enabled NX (Execute Disable) protection: active SMBIOS 2.4 present. Hypervisor detected: KVM Kernel/User page tables isolation: disabled e820: last_pfn = 0x220000 max_arch_pfn = 0x400000000 x86/PAT: Configuration [0-7]: WB WC UC- UC WB WC UC- WT e820: last_pfn = 0xbfff3 max_arch_pfn = 0x400000000 found SMP MP-table at [mem 0x000f2310-0x000f231f] mapped at [ffff8800000f2310] Scanning 1 areas for low memory corruption Using GB pages for direct mapping ACPI: Early table checksum verification disabled ACPI: RSDP 0x00000000000F22D0 000014 (v00 Google) ACPI: RSDT 0x00000000BFFF3430 000038 (v01 Google GOOGRSDT 00000001 GOOG 00000001) ACPI: FACP 0x00000000BFFFCF60 0000F4 (v02 Google GOOGFACP 00000001 GOOG 00000001) ACPI: DSDT 0x00000000BFFF3470 0017B2 (v01 Google GOOGDSDT 00000001 GOOG 00000001) ACPI: FACS 0x00000000BFFFCF00 000040 ACPI: FACS 0x00000000BFFFCF00 000040 ACPI: SSDT 0x00000000BFFF65F0 00690D (v01 Google GOOGSSDT 00000001 GOOG 00000001) ACPI: APIC 0x00000000BFFF5D10 000076 (v01 Google GOOGAPIC 00000001 GOOG 00000001) ACPI: WAET 0x00000000BFFF5CE0 000028 (v01 Google GOOGWAET 00000001 GOOG 00000001) ACPI: SRAT 0x00000000BFFF4C30 0000C8 (v01 Google GOOGSRAT 00000001 GOOG 00000001) kvm-clock: Using msrs 4b564d01 and 4b564d00 kvm-clock: cpu 0, msr 2:1fffd001, primary cpu clock kvm-clock: using sched offset of 2556303500 cycles clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns Zone ranges: DMA [mem 0x0000000000001000-0x0000000000ffffff] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] Normal [mem 0x0000000100000000-0x000000021fffffff] Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000000001000-0x000000000009efff] node 0: [mem 0x0000000000100000-0x00000000bfff2fff] node 0: [mem 0x0000000100000000-0x000000021fffffff] Initmem setup node 0 [mem 0x0000000000001000-0x000000021fffffff]