INIT: Entering runlevel: 2 [[36minfo[39;49m] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added 'ci-upstream-kasan-gce-9,10.128.15.201' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 34.583739] ================================================================== [ 34.584931] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 34.586288] Write of size 8 at addr ffff8801d1c1b640 by task syzkaller639264/3015 [ 34.587334] [ 34.587567] CPU: 0 PID: 3015 Comm: syzkaller639264 Not tainted 4.13.0+ #66 [ 34.588840] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.590220] Call Trace: [ 34.590581] dump_stack+0x194/0x257 [ 34.591072] ? arch_local_irq_restore+0x53/0x53 [ 34.591775] ? show_regs_print_info+0x65/0x65 [ 34.592393] ? __kernel_text_address+0xae/0xe0 [ 34.593003] ? __internal_add_timer+0x275/0x2d0 [ 34.593674] print_address_description+0x73/0x250 [ 34.594537] ? __internal_add_timer+0x275/0x2d0 [ 34.595255] kasan_report+0x24e/0x340 [ 34.595843] __asan_report_store8_noabort+0x17/0x20 [ 34.596657] __internal_add_timer+0x275/0x2d0 [ 34.597261] ? calc_wheel_index+0x200/0x200 [ 34.597897] mod_timer+0x622/0x15b0 [ 34.598406] ? mod_timer_pending+0x14e0/0x14e0 [ 34.599072] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 34.599880] ? trace_hardirqs_on+0xd/0x10 [ 34.600551] ? _crng_backtrack_protect+0xd9/0x130 [ 34.601282] ? __lock_is_held+0xb6/0x140 [ 34.601894] ? lockdep_init_map+0xe4/0x650 [ 34.602519] ? init_timer_key+0x126/0x3b0 [ 34.603245] ? try_to_del_timer_sync+0x120/0x120 [ 34.603989] ? round_jiffies_up+0xce/0x100 [ 34.608192] ? __round_jiffies_up_relative+0x150/0x150 [ 34.613437] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 34.618347] __tun_chr_ioctl+0x1b20/0x3d60 [ 34.622548] ? unwind_dump+0x4/0x4c0 [ 34.626237] ? tun_select_queue+0x580/0x580 [ 34.630527] ? check_noncircular+0x20/0x20 [ 34.634728] ? save_stack+0xa3/0xd0 [ 34.638330] ? __handle_mm_fault+0x577/0x3860 [ 34.642803] ? check_noncircular+0x20/0x20 [ 34.647007] ? check_noncircular+0x20/0x20 [ 34.651206] ? __pmd_alloc+0x4e0/0x4e0 [ 34.655076] ? check_same_owner+0x320/0x320 [ 34.659365] ? handle_mm_fault+0x23e/0x860 [ 34.663586] ? tun_chr_compat_ioctl+0x30/0x30 [ 34.668045] tun_chr_ioctl+0x2a/0x40 [ 34.671723] ? tun_chr_ioctl+0x2a/0x40 [ 34.675581] do_vfs_ioctl+0x1b1/0x1520 [ 34.679440] ? ioctl_preallocate+0x2b0/0x2b0 [ 34.683820] ? selinux_capable+0x40/0x40 [ 34.687852] ? __handle_mm_fault+0x3860/0x3860 [ 34.692428] ? security_file_ioctl+0x7d/0xb0 [ 34.696801] ? security_file_ioctl+0x89/0xb0 [ 34.701180] SyS_ioctl+0x8f/0xc0 [ 34.704526] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 34.709246] RIP: 0033:0x443d79 [ 34.712400] RSP: 002b:00007ffc8b001f98 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 34.720073] RAX: ffffffffffffffda RBX: f1ce4a65c3b97a7a RCX: 0000000000443d79 [ 34.727309] RDX: 0000000020927fd8 RSI: 00000000400454ca RDI: 0000000000000004 [ 34.734551] RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 [ 34.741786] R10: 0000000000000000 R11: 0000000000000202 R12: d7c29eea7c696697 [ 34.749041] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 34.756292] [ 34.757886] Allocated by task 3015: [ 34.761480] save_stack_trace+0x16/0x20 [ 34.765418] save_stack+0x43/0xd0 [ 34.768836] kasan_kmalloc+0xad/0xe0 [ 34.772516] __kmalloc_node+0x47/0x70 [ 34.776283] kvmalloc_node+0x64/0xd0 [ 34.779976] alloc_netdev_mqs+0x16e/0xed0 [ 34.784532] __tun_chr_ioctl+0x12b2/0x3d60 [ 34.788733] tun_chr_ioctl+0x2a/0x40 [ 34.792413] do_vfs_ioctl+0x1b1/0x1520 [ 34.796264] SyS_ioctl+0x8f/0xc0 [ 34.799609] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 34.804342] [ 34.805932] Freed by task 3015: [ 34.809183] save_stack_trace+0x16/0x20 [ 34.813122] save_stack+0x43/0xd0 [ 34.816541] kasan_slab_free+0x71/0xc0 [ 34.820394] kfree+0xca/0x250 [ 34.823463] kvfree+0x36/0x60 [ 34.826561] free_netdev+0x2cf/0x360 [ 34.830249] __tun_chr_ioctl+0x2d24/0x3d60 [ 34.834461] tun_chr_ioctl+0x2a/0x40 [ 34.838138] do_vfs_ioctl+0x1b1/0x1520 [ 34.841988] SyS_ioctl+0x8f/0xc0 [ 34.845319] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 34.850035] [ 34.851628] The buggy address belongs to the object at ffff8801d1c18300 [ 34.851628] which belongs to the cache kmalloc-16384 of size 16384 [ 34.864593] The buggy address is located 13120 bytes inside of [ 34.864593] 16384-byte region [ffff8801d1c18300, ffff8801d1c1c300) [ 34.876783] The buggy address belongs to the page: [ 34.881677] page:ffffea0007470600 count:1 mapcount:0 mapping:ffff8801d1c18300 index:0x0 compound_mapcount: 0 [ 34.891611] flags: 0x200000000008100(slab|head) [ 34.896249] raw: 0200000000008100 ffff8801d1c18300 0000000000000000 0000000100000001 [ 34.904094] raw: ffffea000762aa20 ffffea0007445420 ffff8801dac02200 0000000000000000 [ 34.911937] page dumped because: kasan: bad access detected [ 34.917609] [ 34.919201] Memory state around the buggy address: [ 34.924106] ffff8801d1c1b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.931430] ffff8801d1c1b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.938760] >ffff8801d1c1b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.946096] ^ [ 34.951508] ffff8801d1c1b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.958831] ffff8801d1c1b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.966153] ================================================================== [ 34.973474] Disabling lock debugging due to kernel taint [ 34.978887] Kernel panic - not syncing: panic_on_warn set ... [ 34.978887] [ 34.986214] CPU: 0 PID: 3015 Comm: syzkaller639264 Tainted: G B 4.13.0+ #66 [ 34.994403] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.003718] Call Trace: [ 35.006311] dump_stack+0x194/0x257 [ 35.009904] ? arch_local_irq_restore+0x53/0x53 [ 35.014536] ? kasan_end_report+0x32/0x50 [ 35.018648] ? lock_downgrade+0x990/0x990 [ 35.022759] ? __internal_add_timer+0x210/0x2d0 [ 35.027395] panic+0x1e4/0x417 [ 35.030553] ? __warn+0x1d9/0x1d9 [ 35.033976] ? __internal_add_timer+0x275/0x2d0 [ 35.038609] kasan_end_report+0x50/0x50 [ 35.042562] kasan_report+0x137/0x340 [ 35.046332] __asan_report_store8_noabort+0x17/0x20 [ 35.051314] __internal_add_timer+0x275/0x2d0 [ 35.055775] ? calc_wheel_index+0x200/0x200 [ 35.060065] mod_timer+0x622/0x15b0 [ 35.063663] ? mod_timer_pending+0x14e0/0x14e0 [ 35.068210] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 35.073191] ? trace_hardirqs_on+0xd/0x10 [ 35.077303] ? _crng_backtrack_protect+0xd9/0x130 [ 35.082131] ? __lock_is_held+0xb6/0x140 [ 35.086171] ? lockdep_init_map+0xe4/0x650 [ 35.090385] ? init_timer_key+0x126/0x3b0 [ 35.094497] ? try_to_del_timer_sync+0x120/0x120 [ 35.099218] ? round_jiffies_up+0xce/0x100 [ 35.103432] ? __round_jiffies_up_relative+0x150/0x150 [ 35.108689] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 35.113590] __tun_chr_ioctl+0x1b20/0x3d60 [ 35.117793] ? unwind_dump+0x4/0x4c0 [ 35.121481] ? tun_select_queue+0x580/0x580 [ 35.125768] ? check_noncircular+0x20/0x20 [ 35.129989] ? save_stack+0xa3/0xd0 [ 35.133581] ? __handle_mm_fault+0x577/0x3860 [ 35.138037] ? check_noncircular+0x20/0x20 [ 35.142236] ? check_noncircular+0x20/0x20 [ 35.146433] ? __pmd_alloc+0x4e0/0x4e0 [ 35.150294] ? check_same_owner+0x320/0x320 [ 35.154577] ? handle_mm_fault+0x23e/0x860 [ 35.158776] ? tun_chr_compat_ioctl+0x30/0x30 [ 35.163234] tun_chr_ioctl+0x2a/0x40 [ 35.166919] ? tun_chr_ioctl+0x2a/0x40 [ 35.170790] do_vfs_ioctl+0x1b1/0x1520 [ 35.174643] ? ioctl_preallocate+0x2b0/0x2b0 [ 35.179021] ? selinux_capable+0x40/0x40 [ 35.183050] ? __handle_mm_fault+0x3860/0x3860 [ 35.187603] ? security_file_ioctl+0x7d/0xb0 [ 35.191973] ? security_file_ioctl+0x89/0xb0 [ 35.196357] SyS_ioctl+0x8f/0xc0 [ 35.199690] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 35.204409] RIP: 0033:0x443d79 [ 35.207564] RSP: 002b:00007ffc8b001f98 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 35.215238] RAX: ffffffffffffffda RBX: f1ce4a65c3b97a7a RCX: 0000000000443d79 [ 35.222487] RDX: 0000000020927fd8 RSI: 00000000400454ca RDI: 0000000000000004 [ 35.229719] RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 [ 35.236953] R10: 0000000000000000 R11: 0000000000000202 R12: d7c29eea7c696697 [ 35.244197] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000