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 '10.128.10.28' (ECDSA) to the list of known hosts. 2018/04/02 16:32:12 parsed 1 programs 2018/04/02 16:32:12 executed programs: 0 syzkaller login: [ 27.351256] IPVS: Creating netns size=2536 id=1 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 RESULT: signal 0, coverage 0 errno 0 [ 32.018172] ================================================================== [ 32.025547] BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xe8/0x100 [ 32.032785] Read of size 4 at addr ffff8801c604d400 by task syz-executor0/3894 [ 32.040107] [ 32.041707] CPU: 0 PID: 3894 Comm: syz-executor0 Not tainted 4.9.92-g9c3fb9c #10 [ 32.049205] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.058528] ffff8801d813fc98 ffffffff81d95109 ffffea0007181300 ffff8801c604d400 [ 32.066499] 0000000000000000 ffff8801c604d400 ffffffff82ed79f0 ffff8801d813fcd0 [ 32.074459] ffffffff8153d5d3 ffff8801c604d400 0000000000000004 0000000000000000 [ 32.082421] Call Trace: [ 32.084974] [] dump_stack+0xc1/0x128 [ 32.090306] [] ? sock_release+0x1e0/0x1e0 [ 32.096072] [] print_address_description+0x73/0x280 [ 32.102704] [] ? sock_release+0x1e0/0x1e0 [ 32.108466] [] kasan_report+0x255/0x380 [ 32.114057] [] ? l2tp_session_queue_purge+0xe8/0x100 [ 32.120775] [] __asan_report_load4_noabort+0x14/0x20 [ 32.127492] [] l2tp_session_queue_purge+0xe8/0x100 [ 32.134037] [] ? sock_release+0x1e0/0x1e0 [ 32.139801] [] pppol2tp_release+0x1ff/0x2e0 [ 32.145739] [] sock_release+0x8d/0x1e0 [ 32.151241] [] sock_close+0x16/0x20 [ 32.156483] [] __fput+0x28c/0x6e0 [ 32.161555] [] ____fput+0x15/0x20 [ 32.166633] [] task_work_run+0x115/0x190 [ 32.172313] [] exit_to_usermode_loop+0xfc/0x120 [ 32.178614] [] do_fast_syscall_32+0x5c1/0x870 [ 32.184732] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.191365] [] entry_SYSENTER_compat+0x90/0xa2 [ 32.197560] [ 32.199161] Allocated by task 3894: [ 32.202756] save_stack_trace+0x16/0x20 [ 32.206696] save_stack+0x43/0xd0 [ 32.210122] kasan_kmalloc+0xad/0xe0 [ 32.213801] __kmalloc+0x11d/0x310 [ 32.217308] l2tp_session_create+0x38/0x1770 [ 32.221683] pppol2tp_connect+0x10fe/0x18f0 [ 32.225971] SYSC_connect+0x1b6/0x310 [ 32.229739] SyS_connect+0x24/0x30 [ 32.233245] do_fast_syscall_32+0x2f5/0x870 [ 32.237531] entry_SYSENTER_compat+0x90/0xa2 [ 32.241903] [ 32.243499] Freed by task 3893: [ 32.246742] save_stack_trace+0x16/0x20 [ 32.250683] save_stack+0x43/0xd0 [ 32.254107] kasan_slab_free+0x72/0xc0 [ 32.257959] kfree+0x103/0x300 [ 32.261120] l2tp_session_free+0x166/0x200 [ 32.265322] l2tp_tunnel_closeall+0x26c/0x3a0 [ 32.269781] l2tp_udp_encap_destroy+0x87/0xe0 [ 32.274242] udpv6_destroy_sock+0xb1/0xd0 [ 32.278358] sk_common_release+0x6b/0x2f0 [ 32.282468] udp_lib_close+0x15/0x20 [ 32.286154] inet_release+0xfa/0x1d0 [ 32.289836] inet6_release+0x50/0x70 [ 32.293518] sock_release+0x8d/0x1e0 [ 32.297197] sock_close+0x16/0x20 [ 32.300614] __fput+0x28c/0x6e0 [ 32.303860] ____fput+0x15/0x20 [ 32.307109] task_work_run+0x115/0x190 [ 32.310964] exit_to_usermode_loop+0xfc/0x120 [ 32.315438] do_fast_syscall_32+0x5c1/0x870 [ 32.319726] entry_SYSENTER_compat+0x90/0xa2 [ 32.324104] [ 32.325699] The buggy address belongs to the object at ffff8801c604d400 [ 32.325699] which belongs to the cache kmalloc-512 of size 512 [ 32.338329] The buggy address is located 0 bytes inside of [ 32.338329] 512-byte region [ffff8801c604d400, ffff8801c604d600) [ 32.350003] The buggy address belongs to the page: [ 32.354906] page:ffffea0007181300 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 32.365073] flags: 0x8000000000004080(slab|head) [ 32.369791] page dumped because: kasan: bad access detected [ 32.375480] [ 32.377074] Memory state around the buggy address: [ 32.381970] ffff8801c604d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.389309] ffff8801c604d380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 32.396719] >ffff8801c604d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.404042] ^ [ 32.407376] ffff8801c604d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.414701] ffff8801c604d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.422024] ================================================================== [ 32.429344] Disabling lock debugging due to kernel taint [ 32.434964] Kernel panic - not syncing: panic_on_warn set ... [ 32.434964] [ 32.442300] CPU: 0 PID: 3894 Comm: syz-executor0 Tainted: G B 4.9.92-g9c3fb9c #10 [ 32.451013] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.460333] ffff8801d813fbf0 ffffffff81d95109 ffffffff84197d5f ffff8801d813fcc8 [ 32.468299] 0000000000000000 ffff8801c604d400 ffffffff82ed79f0 ffff8801d813fcb8 [ 32.476259] ffffffff8142e791 0000000041b58ab3 ffffffff8418b7b8 ffffffff8142e5d5 [ 32.484257] Call Trace: [ 32.486819] [] dump_stack+0xc1/0x128 [ 32.492152] [] ? sock_release+0x1e0/0x1e0 [ 32.497918] [] panic+0x1bc/0x3a8 [ 32.502899] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 32.511099] [] ? preempt_schedule+0x25/0x30 [ 32.517037] [] ? ___preempt_schedule+0x16/0x18 [ 32.523236] [] kasan_end_report+0x50/0x50 [ 32.528998] [] kasan_report+0x16b/0x380 [ 32.534592] [] ? l2tp_session_queue_purge+0xe8/0x100 [ 32.541312] [] __asan_report_load4_noabort+0x14/0x20 [ 32.548033] [] l2tp_session_queue_purge+0xe8/0x100 [ 32.554581] [] ? sock_release+0x1e0/0x1e0 [ 32.560345] [] pppol2tp_release+0x1ff/0x2e0 [ 32.566284] [] sock_release+0x8d/0x1e0 [ 32.571786] [] sock_close+0x16/0x20 [ 32.577029] [] __fput+0x28c/0x6e0 [ 32.582100] [] ____fput+0x15/0x20 [ 32.587169] [] task_work_run+0x115/0x190 [ 32.592845] [] exit_to_usermode_loop+0xfc/0x120 [ 32.599133] [] do_fast_syscall_32+0x5c1/0x870 [ 32.605243] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.611873] [] entry_SYSENTER_compat+0x90/0xa2 [ 32.618446] Dumping ftrace buffer: [ 32.621954] (ftrace buffer empty) [ 32.625633] Kernel Offset: disabled [ 32.629230] Rebooting in 86400 seconds..