INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.43' (ECDSA) to the list of known hosts. 2018/04/09 06:08:26 parsed 1 programs 2018/04/09 06:08:26 executed programs: 0 syzkaller login: [ 46.393314] IPVS: Creating netns size=2536 id=1 [ 47.381292] ================================================================== [ 47.388829] BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xf4/0x100 [ 47.396078] Read of size 4 at addr ffff8801c2887b80 by task syz-executor0/3820 [ 47.403407] [ 47.405007] CPU: 0 PID: 3820 Comm: syz-executor0 Not tainted 4.9.92-g4fb542f #2 [ 47.412421] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.421934] ffff8801d8987ca0 ffffffff81d9c509 ffffea00070a2180 ffff8801c2887b80 [ 47.429917] 0000000000000000 ffff8801c2887b80 ffffffff82ef0be0 ffff8801d8987cd8 [ 47.437889] ffffffff8156556b ffff8801c2887b80 0000000000000004 0000000000000000 [ 47.445903] Call Trace: [ 47.448471] [] dump_stack+0xc1/0x128 [ 47.453809] [] ? sock_release+0x1c0/0x1c0 [ 47.459582] [] print_address_description+0x6c/0x234 [ 47.466218] [] ? sock_release+0x1c0/0x1c0 [ 47.471989] [] kasan_report.cold.6+0xac/0x2f5 [ 47.478346] [] ? l2tp_session_queue_purge+0xf4/0x100 [ 47.485065] [] __asan_report_load4_noabort+0x14/0x20 [ 47.491784] [] l2tp_session_queue_purge+0xf4/0x100 [ 47.498332] [] ? sock_release+0x1c0/0x1c0 [ 47.504097] [] pppol2tp_release+0x1fb/0x2e0 [ 47.510035] [] sock_release+0x96/0x1c0 [ 47.515549] [] sock_close+0x16/0x20 [ 47.520796] [] __fput+0x263/0x700 [ 47.525870] [] ____fput+0x15/0x20 [ 47.530956] [] task_work_run+0x10c/0x180 [ 47.536643] [] exit_to_usermode_loop+0xfc/0x120 [ 47.542946] [] do_fast_syscall_32+0x5c3/0x870 [ 47.549081] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 47.555720] [] entry_SYSENTER_compat+0x90/0xa2 [ 47.561918] [ 47.563519] Allocated by task 3820: [ 47.567309] save_stack_trace+0x16/0x20 [ 47.571262] save_stack+0x43/0xd0 [ 47.574683] kasan_kmalloc+0xc7/0xe0 [ 47.578371] __kmalloc+0x11d/0x300 [ 47.581899] l2tp_session_create+0x38/0x1760 [ 47.586275] pppol2tp_connect+0x10c5/0x18e0 [ 47.590567] SYSC_connect+0x1b8/0x300 [ 47.594337] SyS_connect+0x24/0x30 [ 47.597847] do_fast_syscall_32+0x2f7/0x870 [ 47.602147] entry_SYSENTER_compat+0x90/0xa2 [ 47.606519] [ 47.608117] Freed by task 3819: [ 47.611366] save_stack_trace+0x16/0x20 [ 47.615398] save_stack+0x43/0xd0 [ 47.618818] kasan_slab_free+0x72/0xc0 [ 47.622680] kfree+0xfb/0x310 [ 47.625763] l2tp_session_free+0x166/0x200 [ 47.630071] l2tp_tunnel_closeall+0x284/0x350 [ 47.634538] l2tp_udp_encap_destroy+0x87/0xe0 [ 47.639005] udpv6_destroy_sock+0xb1/0xd0 [ 47.643216] sk_common_release+0x6d/0x300 [ 47.647349] udp_lib_close+0x15/0x20 [ 47.651035] inet_release+0xff/0x1d0 [ 47.654732] inet6_release+0x50/0x70 [ 47.658420] sock_release+0x96/0x1c0 [ 47.662106] sock_close+0x16/0x20 [ 47.665534] __fput+0x263/0x700 [ 47.668793] ____fput+0x15/0x20 [ 47.672049] task_work_run+0x10c/0x180 [ 47.675910] exit_to_usermode_loop+0xfc/0x120 [ 47.680377] do_fast_syscall_32+0x5c3/0x870 [ 47.684672] entry_SYSENTER_compat+0x90/0xa2 [ 47.689047] [ 47.690652] The buggy address belongs to the object at ffff8801c2887b80 [ 47.690652] which belongs to the cache kmalloc-512 of size 512 [ 47.703369] The buggy address is located 0 bytes inside of [ 47.703369] 512-byte region [ffff8801c2887b80, ffff8801c2887d80) [ 47.715223] The buggy address belongs to the page: [ 47.720133] page:ffffea00070a2180 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 47.730304] flags: 0x8000000000004080(slab|head) [ 47.735029] page dumped because: kasan: bad access detected [ 47.740706] [ 47.742305] Memory state around the buggy address: [ 47.747215] ffff8801c2887a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.754547] ffff8801c2887b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 47.761874] >ffff8801c2887b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.769208] ^ [ 47.772560] ffff8801c2887c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.779898] ffff8801c2887c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.787223] ================================================================== [ 47.794566] Disabling lock debugging due to kernel taint [ 47.800242] Kernel panic - not syncing: panic_on_warn set ... [ 47.800242] [ 47.807583] CPU: 0 PID: 3820 Comm: syz-executor0 Tainted: G B 4.9.92-g4fb542f #2 [ 47.816214] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.825548] ffff8801d8987c00 ffffffff81d9c509 ffffffff841a85f1 00000000ffffffff [ 47.833517] 0000000000000000 0000000000000000 ffffffff82ef0be0 ffff8801d8987cc0 [ 47.841492] ffffffff8141fa55 0000000041b58ab3 ffffffff8419bd28 ffffffff8141f896 [ 47.849453] Call Trace: [ 47.852017] [] dump_stack+0xc1/0x128 [ 47.857356] [] ? sock_release+0x1c0/0x1c0 [ 47.863132] [] panic+0x1bf/0x3bc [ 47.868121] [] ? add_taint.cold.6+0x16/0x16 [ 47.874067] [] ? ___preempt_schedule+0x16/0x18 [ 47.880275] [] kasan_end_report+0x47/0x4f [ 47.886044] [] kasan_report.cold.6+0xc9/0x2f5 [ 47.892172] [] ? l2tp_session_queue_purge+0xf4/0x100 [ 47.898917] [] __asan_report_load4_noabort+0x14/0x20 [ 47.905652] [] l2tp_session_queue_purge+0xf4/0x100 [ 47.912208] [] ? sock_release+0x1c0/0x1c0 [ 47.917981] [] pppol2tp_release+0x1fb/0x2e0 [ 47.923924] [] sock_release+0x96/0x1c0 [ 47.929431] [] sock_close+0x16/0x20 [ 47.934683] [] __fput+0x263/0x700 [ 47.939756] [] ____fput+0x15/0x20 [ 47.944835] [] task_work_run+0x10c/0x180 [ 47.950518] [] exit_to_usermode_loop+0xfc/0x120 [ 47.956807] [] do_fast_syscall_32+0x5c3/0x870 [ 47.962936] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 47.969580] [] entry_SYSENTER_compat+0x90/0xa2 [ 47.976256] Dumping ftrace buffer: [ 47.979770] (ftrace buffer empty) [ 47.983455] Kernel Offset: disabled [ 47.987056] Rebooting in 86400 seconds..