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-1,10.128.0.20' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 41.339849] ================================================================== [ 41.340953] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 41.341902] Write of size 8 at addr ffff8801d219b500 by task syzkaller159730/2987 [ 41.342927] [ 41.343162] CPU: 1 PID: 2987 Comm: syzkaller159730 Not tainted 4.14.0-rc5+ #142 [ 41.344136] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.345355] Call Trace: [ 41.345713] dump_stack+0x194/0x257 [ 41.346203] ? arch_local_irq_restore+0x53/0x53 [ 41.346849] ? show_regs_print_info+0x65/0x65 [ 41.347453] ? __kernel_text_address+0xd/0x40 [ 41.348052] ? __internal_add_timer+0x275/0x2d0 [ 41.348676] print_address_description+0x73/0x250 [ 41.349320] ? __internal_add_timer+0x275/0x2d0 [ 41.349943] kasan_report+0x25b/0x340 [ 41.350459] __asan_report_store8_noabort+0x17/0x20 [ 41.351137] __internal_add_timer+0x275/0x2d0 [ 41.351738] ? calc_wheel_index+0x200/0x200 [ 41.352325] mod_timer+0x622/0x15b0 [ 41.352824] ? mod_timer_pending+0x14e0/0x14e0 [ 41.353437] ? __lock_is_held+0xb6/0x140 [ 41.354013] ? __lock_is_held+0xb6/0x140 [ 41.354564] ? __lockdep_init_map+0xe4/0x650 [ 41.355156] ? lockdep_init_map+0x9/0x10 [ 41.355699] ? init_timer_key+0x126/0x3b0 [ 41.356256] ? try_to_del_timer_sync+0x120/0x120 [ 41.356890] ? round_jiffies_up+0xce/0x100 [ 41.357455] ? __round_jiffies_up_relative+0x150/0x150 [ 41.358170] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 41.358825] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 41.359564] __tun_chr_ioctl+0x1b17/0x3d20 [ 41.360994] ? tun_chr_read_iter+0x1e0/0x1e0 [ 41.365365] ? find_held_lock+0x35/0x1d0 [ 41.369402] ? __do_page_fault+0x64c/0xd60 [ 41.373606] ? lock_downgrade+0x990/0x990 [ 41.377728] ? handle_mm_fault+0x410/0x8d0 [ 41.381944] ? check_same_owner+0x320/0x320 [ 41.386230] ? up_read+0x1a/0x40 [ 41.389563] ? __do_page_fault+0x3d6/0xd60 [ 41.393767] ? tun_chr_compat_ioctl+0x30/0x30 [ 41.398229] tun_chr_ioctl+0x2a/0x40 [ 41.401910] ? tun_chr_ioctl+0x2a/0x40 [ 41.405769] do_vfs_ioctl+0x1b1/0x1520 [ 41.409630] ? ioctl_preallocate+0x2b0/0x2b0 [ 41.414006] ? selinux_capable+0x40/0x40 [ 41.418041] ? syscall_return_slowpath+0x2b3/0x510 [ 41.422945] ? security_file_ioctl+0x89/0xb0 [ 41.427321] SyS_ioctl+0x8f/0xc0 [ 41.430659] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 41.435377] RIP: 0033:0x443dc9 [ 41.438532] RSP: 002b:00007ffe30b2ad28 EFLAGS: 00000203 ORIG_RAX: 0000000000000010 [ 41.446202] RAX: ffffffffffffffda RBX: 92b7c5cdcceb9f57 RCX: 0000000000443dc9 [ 41.453437] RDX: 000000002087ffd8 RSI: 00000000400454ca RDI: 0000000000000005 [ 41.460674] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 41.467907] R10: 0000000000000000 R11: 0000000000000203 R12: ce8808c2878d3ab8 [ 41.475144] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 41.482394] [ 41.483988] Allocated by task 2987: [ 41.487578] save_stack_trace+0x16/0x20 [ 41.491516] save_stack+0x43/0xd0 [ 41.494933] kasan_kmalloc+0xad/0xe0 [ 41.498610] __kmalloc_node+0x47/0x70 [ 41.502374] kvmalloc_node+0x64/0xd0 [ 41.506055] alloc_netdev_mqs+0x16e/0xed0 [ 41.510164] __tun_chr_ioctl+0x12b2/0x3d20 [ 41.514362] tun_chr_ioctl+0x2a/0x40 [ 41.518040] do_vfs_ioctl+0x1b1/0x1520 [ 41.521891] SyS_ioctl+0x8f/0xc0 [ 41.525237] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 41.529955] [ 41.531547] Freed by task 2987: [ 41.534790] save_stack_trace+0x16/0x20 [ 41.538731] save_stack+0x43/0xd0 [ 41.542149] kasan_slab_free+0x71/0xc0 [ 41.545999] kfree+0xca/0x250 [ 41.549070] kvfree+0x36/0x60 [ 41.552139] free_netdev+0x2cf/0x360 [ 41.555814] __tun_chr_ioctl+0x2cea/0x3d20 [ 41.560009] tun_chr_ioctl+0x2a/0x40 [ 41.563685] do_vfs_ioctl+0x1b1/0x1520 [ 41.567534] SyS_ioctl+0x8f/0xc0 [ 41.570864] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 41.575582] [ 41.577176] The buggy address belongs to the object at ffff8801d21981c0 [ 41.577176] which belongs to the cache kmalloc-16384 of size 16384 [ 41.590143] The buggy address is located 13120 bytes inside of [ 41.590143] 16384-byte region [ffff8801d21981c0, ffff8801d219c1c0) [ 41.602323] The buggy address belongs to the page: [ 41.607218] page:ffffea0007486600 count:1 mapcount:0 mapping:ffff8801d21981c0 index:0x0 compound_mapcount: 0 [ 41.617149] flags: 0x200000000008100(slab|head) [ 41.621788] raw: 0200000000008100 ffff8801d21981c0 0000000000000000 0000000100000001 [ 41.629632] raw: ffffea000765a020 ffffea000747f020 ffff8801dac02200 0000000000000000 [ 41.637472] page dumped because: kasan: bad access detected [ 41.643145] [ 41.644735] Memory state around the buggy address: [ 41.649626] ffff8801d219b400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.656954] ffff8801d219b480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.664278] >ffff8801d219b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.671598] ^ [ 41.674929] ffff8801d219b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.682251] ffff8801d219b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.689570] ================================================================== [ 41.696891] Disabling lock debugging due to kernel taint [ 41.702305] Kernel panic - not syncing: panic_on_warn set ... [ 41.702305] [ 41.709629] CPU: 1 PID: 2987 Comm: syzkaller159730 Tainted: G B 4.14.0-rc5+ #142 [ 41.718251] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.727569] Call Trace: [ 41.730124] dump_stack+0x194/0x257 [ 41.733718] ? arch_local_irq_restore+0x53/0x53 [ 41.738350] ? kasan_end_report+0x32/0x50 [ 41.742461] ? lock_downgrade+0x990/0x990 [ 41.746573] ? __internal_add_timer+0x1f0/0x2d0 [ 41.751206] panic+0x1e4/0x417 [ 41.754364] ? __warn+0x1d9/0x1d9 [ 41.757787] ? __internal_add_timer+0x275/0x2d0 [ 41.762417] kasan_end_report+0x50/0x50 [ 41.766353] kasan_report+0x144/0x340 [ 41.770123] __asan_report_store8_noabort+0x17/0x20 [ 41.775103] __internal_add_timer+0x275/0x2d0 [ 41.779562] ? calc_wheel_index+0x200/0x200 [ 41.783853] mod_timer+0x622/0x15b0 [ 41.787449] ? mod_timer_pending+0x14e0/0x14e0 [ 41.791993] ? __lock_is_held+0xb6/0x140 [ 41.796024] ? __lock_is_held+0xb6/0x140 [ 41.800052] ? __lockdep_init_map+0xe4/0x650 [ 41.804425] ? lockdep_init_map+0x9/0x10 [ 41.808446] ? init_timer_key+0x126/0x3b0 [ 41.812558] ? try_to_del_timer_sync+0x120/0x120 [ 41.817278] ? round_jiffies_up+0xce/0x100 [ 41.821474] ? __round_jiffies_up_relative+0x150/0x150 [ 41.827225] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 41.832118] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 41.837622] __tun_chr_ioctl+0x1b17/0x3d20 [ 41.841825] ? tun_chr_read_iter+0x1e0/0x1e0 [ 41.846197] ? find_held_lock+0x35/0x1d0 [ 41.850226] ? __do_page_fault+0x64c/0xd60 [ 41.854425] ? lock_downgrade+0x990/0x990 [ 41.858541] ? handle_mm_fault+0x410/0x8d0 [ 41.862746] ? check_same_owner+0x320/0x320 [ 41.867033] ? up_read+0x1a/0x40 [ 41.870363] ? __do_page_fault+0x3d6/0xd60 [ 41.874562] ? tun_chr_compat_ioctl+0x30/0x30 [ 41.879022] tun_chr_ioctl+0x2a/0x40 [ 41.882698] ? tun_chr_ioctl+0x2a/0x40 [ 41.886549] do_vfs_ioctl+0x1b1/0x1520 [ 41.890403] ? ioctl_preallocate+0x2b0/0x2b0 [ 41.894775] ? selinux_capable+0x40/0x40 [ 41.898804] ? syscall_return_slowpath+0x2b3/0x510 [ 41.903703] ? security_file_ioctl+0x89/0xb0 [ 41.908076] SyS_ioctl+0x8f/0xc0 [ 41.911412] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 41.916132] RIP: 0033:0x443dc9 [ 41.919285] RSP: 002b:00007ffe30b2ad28 EFLAGS: 00000203 ORIG_RAX: 0000000000000010 [ 41.926957] RAX: ffffffffffffffda RBX: 92b7c5cdcceb9f57 RCX: 0000000000443dc9 [ 41.934190] RDX: 000000002087ffd8 RSI: 00000000400454ca RDI: 0000000000000005 [ 41.941423] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 41.948656] R10: 0000000000000000 R11: 0000000000000203 R12: ce8808c2878d3ab8 [ 41.955891] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 41.963167] Dumping ftrace buffer: [ 41.966670] (ftrace buffer empty) [ 41.970346] Kernel Offset: disabled [ 41.973940] Rebooting in 86400 seconds..