binder: BINDER_SET_CONTEXT_MGR already set binder: 11569:11584 ioctl 40046207 0 returned -16 binder: 11569:11572 unknown command 1017371462 binder: 11569:11572 ioctl c0306201 20007000 returned -22 ================================================================== BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 net/l2tp/l2tp_core.c:830 Read of size 4 at addr ffff8800b5f21900 by task syz-executor5/11568 CPU: 1 PID: 11568 Comm: syz-executor5 Not tainted 4.4.151-g727cfac #87 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 166d501754d98a8f ffff8800b2a47cb8 ffffffff81e15eed ffffea0002d7c800 ffff8800b5f21900 0000000000000000 ffff8800b5f21900 0000000000000000 ffff8800b2a47cf0 ffffffff8151b390 ffff8800b5f21900 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+0xd9/0x260 net/socket.c:592 [] sock_close+0x19/0x20 net/socket.c:1050 [] __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:253 [] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline] [] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:349 [] int_ret_from_sys_call+0x25/0xa3 Allocated by task 11555: [] 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:1570 [] SyS_connect+0x24/0x30 net/socket.c:1551 [] entry_SYSCALL_64_fastpath+0x22/0x9e Freed by task 11555: [] 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+0xd9/0x260 net/socket.c:592 [] sock_close+0x19/0x20 net/socket.c:1050 [] __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:253 [] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline] [] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:349 [] int_ret_from_sys_call+0x25/0xa3 The buggy address belongs to the object at ffff8800b5f21900 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes inside of 512-byte region [ffff8800b5f21900, ffff8800b5f21b00) The buggy address belongs to the page: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [< (null)>] (null) PGD 1c1413067 PUD 1c1414067 PMD 0 Oops: 0010 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.151-g727cfac #87 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffffffff84417840 task.stack: ffffffff84400000 RIP: 0010:[<0000000000000000>] [< (null)>] (null) RSP: 0018:ffff8801db207db0 EFLAGS: 00010006 RAX: ffffffff84417840 RBX: ffff8800b0c1f410 RCX: 0000000000000000 RDX: 0000000000010000 RSI: ffffffff812a0e55 RDI: ffff8800b0c1f410 RBP: ffff8801db207ee0 R08: ffffffff8532c320 R09: 0000000000000001 R10: 0000000000000000 R11: ffffffff84417840 R12: 0000000000000000 R13: ffff8801db2196c0 R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000001c1412000 CR4: 00000000001606f0 Stack: ffffffff812a0e5d 0000000000000046 ffff8801db207e78 ffffffff84417840 1ffff1003b640fc3 ffff8801db219720 ffffed003b640fcf 0000000000000001 ffff8801db219800 0303880200000001 ffff8801db2196f8 ffff8801db219818 Call Trace: [] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1359 [] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:901 [] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:925 [] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741 [] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline] [] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:432 [] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:423 [] default_idle_call+0x57/0x70 kernel/sched/idle.c:93 [] cpuidle_idle_call kernel/sched/idle.c:157 [inline] [] cpu_idle_loop kernel/sched/idle.c:253 [inline] [] cpu_startup_entry+0x6af/0x780 kernel/sched/idle.c:301 [] rest_init+0x188/0x18e init/main.c:410 [] start_kernel+0x6b3/0x6e7 init/main.c:682 [] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196 [] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:185 Code: Bad RIP value. RIP [< (null)>] (null) RSP CR2: 0000000000000000 ---[ end trace bdcde4eaaf89c0dc ]---