IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth0: link is not 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 ffff8801cd657180 by task syz-executor0/4792 CPU: 0 PID: 4792 Comm: syz-executor0 Not tainted 4.4.138-g226f96b #61 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 05745fad912c1808 ffff8801d39afad8 ffffffff81e0ed0d ffffea0007359580 ffff8801cd657180 0000000000000000 ffff8801cd657180 ffffffff82f1a2b0 ffff8801d39afb10 ffffffff81515a16 ffff8801cd657180 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 [] exit_task_work include/linux/task_work.h:21 [inline] [] do_exit+0x9e5/0x26b0 kernel/exit.c:759 [] do_group_exit+0x111/0x330 kernel/exit.c:889 [] SYSC_exit_group kernel/exit.c:900 [inline] [] SyS_exit_group+0x1d/0x20 kernel/exit.c:898 [] 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 Allocated by task 4789: [] 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 4780: [] 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 [] exit_task_work include/linux/task_work.h:21 [inline] [] do_exit+0x9e5/0x26b0 kernel/exit.c:759 [] do_group_exit+0x111/0x330 kernel/exit.c:889 [] SYSC_exit_group kernel/exit.c:900 [inline] [] SyS_exit_group+0x1d/0x20 kernel/exit.c:898 [] 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 The buggy address belongs to the object at ffff8801cd657180 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes inside of 512-byte region [ffff8801cd657180, ffff8801cd657380) The buggy address belongs to the page: kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 3852 Comm: syz-executor0 Not tainted 4.4.138-g226f96b #61 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d8d7b000 task.stack: ffff8800ad400000 RIP: 0010:[] [] slab_alloc_node mm/slub.c:2600 [inline] RIP: 0010:[] [] slab_alloc mm/slub.c:2623 [inline] RIP: 0010:[] [] kmem_cache_alloc+0x7e/0x2a0 mm/slub.c:2628 RSP: 0000:ffff8800ad407b80 EFLAGS: 00010046 RAX: 4f5f4755425f4d56 RBX: 0000000000000000 RCX: 0000000000023960 RDX: 00000000000116c1 RSI: 00000000000116c1 RDI: 0000000000023960 RBP: ffff8800ad407bb0 R08: ffff8801d8d7b928 R09: 0000000000000001 R10: 0000000000000000 R11: ffff8801d8d7b000 R12: ffff8801d98fc8c0 R13: 4f5f4755425f4d56 R14: 0000000002280020 R15: ffffffff81154c01 FS: 0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000092c5900 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 000000008148ced7 CR3: 00000000baef1000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801d8d7b000 ffff8801d8d7b000 ffffffff8448cf80 0000000000000001 0000000002280020 000000000000000b ffff8800ad407bf0 ffffffff81154c01 ffffffff81154a20 ffff8801d8d7b000 0000000000000004 ffff8801d8d7b798 Call Trace: [] __sigqueue_alloc+0x1e1/0x400 kernel/signal.c:380 [] __send_signal+0x1a5/0x11b0 kernel/signal.c:1029 [] send_signal+0x4a/0xc0 kernel/signal.c:1096 [] specific_send_sig_info kernel/signal.c:1141 [inline] [] force_sig_info+0x20a/0x310 kernel/signal.c:1189 [] force_sig_info_fault.constprop.23+0x158/0x1b0 arch/x86/mm/fault.c:187 [] __bad_area_nosemaphore+0x219/0x310 arch/x86/mm/fault.c:807 [] __bad_area arch/x86/mm/fault.c:837 [inline] [] bad_area+0x66/0x80 arch/x86/mm/fault.c:843 [] __do_page_fault+0x767/0xa10 arch/x86/mm/fault.c:1225 [] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1308 [] page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1037 Code: 48 8b 70 08 48 39 f2 75 e7 4c 8b 28 4d 85 ed 0f 84 ec 00 00 00 49 63 44 24 20 49 8b 3c 24 4c 01 e8 40 f6 c7 0f 0f 85 11 01 00 00 <48> 8b 18 48 8d 4a 40 4c 89 e8 65 48 0f c7 0f 0f 94 c0 84 c0 74 RIP [] slab_alloc_node mm/slub.c:2600 [inline] RIP [] slab_alloc mm/slub.c:2623 [inline] RIP [] kmem_cache_alloc+0x7e/0x2a0 mm/slub.c:2628 RSP ---[ end trace 42c741916279add5 ]---