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-0,10.128.0.44' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 33.467639] ================================================================== [ 33.468836] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 33.469774] Write of size 8 at addr ffff8801d0cdb640 by task syzkaller464521/3010 [ 33.470770] [ 33.471003] CPU: 0 PID: 3010 Comm: syzkaller464521 Not tainted 4.13.0-rc7+ #63 [ 33.472036] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.473321] Call Trace: [ 33.473689] dump_stack+0x194/0x257 [ 33.474202] ? arch_local_irq_restore+0x53/0x53 [ 33.474823] ? show_regs_print_info+0x65/0x65 [ 33.475428] ? __kernel_text_address+0xae/0xe0 [ 33.476039] ? __internal_add_timer+0x275/0x2d0 [ 33.476679] print_address_description+0x73/0x250 [ 33.477411] ? __internal_add_timer+0x275/0x2d0 [ 33.478051] kasan_report+0x24e/0x340 [ 33.478566] __asan_report_store8_noabort+0x17/0x20 [ 33.479247] __internal_add_timer+0x275/0x2d0 [ 33.479860] ? calc_wheel_index+0x200/0x200 [ 33.480447] mod_timer+0x622/0x15b0 [ 33.480943] ? mod_timer_pending+0x14e0/0x14e0 [ 33.481555] ? __lock_is_held+0xb6/0x140 [ 33.482118] ? __lock_is_held+0xb6/0x140 [ 33.482669] ? lockdep_init_map+0xe4/0x650 [ 33.483239] ? init_timer_key+0x126/0x3b0 [ 33.483797] ? try_to_del_timer_sync+0x120/0x120 [ 33.484432] ? round_jiffies_up+0xce/0x100 [ 33.485017] ? __round_jiffies_up_relative+0x150/0x150 [ 33.485721] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 33.486377] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 33.487134] __tun_chr_ioctl+0x1b20/0x3d60 [ 33.487710] ? tun_select_queue+0x580/0x580 [ 33.488305] ? check_noncircular+0x20/0x20 [ 33.492505] ? get_unused_fd_flags+0x190/0x190 [ 33.497061] ? __handle_mm_fault+0x577/0x3860 [ 33.501520] ? check_noncircular+0x20/0x20 [ 33.505728] ? check_noncircular+0x20/0x20 [ 33.509927] ? __pmd_alloc+0x4e0/0x4e0 [ 33.513799] ? check_same_owner+0x320/0x320 [ 33.518087] ? handle_mm_fault+0x23e/0x860 [ 33.522294] ? tun_chr_compat_ioctl+0x30/0x30 [ 33.526763] tun_chr_ioctl+0x2a/0x40 [ 33.530447] ? tun_chr_ioctl+0x2a/0x40 [ 33.534303] do_vfs_ioctl+0x1b1/0x1520 [ 33.538163] ? ioctl_preallocate+0x2b0/0x2b0 [ 33.542542] ? selinux_capable+0x40/0x40 [ 33.546574] ? __handle_mm_fault+0x3860/0x3860 [ 33.551137] ? security_file_ioctl+0x7d/0xb0 [ 33.555509] ? security_file_ioctl+0x89/0xb0 [ 33.559886] SyS_ioctl+0x8f/0xc0 [ 33.563224] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 33.567946] RIP: 0033:0x443dd9 [ 33.571103] RSP: 002b:00007fff2fe31ea8 EFLAGS: 00000207 ORIG_RAX: 0000000000000010 [ 33.578780] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443dd9 [ 33.586017] RDX: 0000000020074000 RSI: 00000000400454ca RDI: 0000000000000006 [ 33.593256] RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 [ 33.600494] R10: 0000000000000000 R11: 0000000000000207 R12: e756701d2c7e9737 [ 33.607731] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 33.614995] [ 33.616589] Allocated by task 3010: [ 33.620183] save_stack_trace+0x16/0x20 [ 33.624123] save_stack+0x43/0xd0 [ 33.627540] kasan_kmalloc+0xad/0xe0 [ 33.631218] __kmalloc_node+0x47/0x70 [ 33.634986] kvmalloc_node+0x64/0xd0 [ 33.638666] alloc_netdev_mqs+0x16e/0xed0 [ 33.642781] __tun_chr_ioctl+0x12b2/0x3d60 [ 33.646981] tun_chr_ioctl+0x2a/0x40 [ 33.650660] do_vfs_ioctl+0x1b1/0x1520 [ 33.654512] SyS_ioctl+0x8f/0xc0 [ 33.657846] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 33.662565] [ 33.664158] Freed by task 3010: [ 33.667401] save_stack_trace+0x16/0x20 [ 33.671340] save_stack+0x43/0xd0 [ 33.674762] kasan_slab_free+0x71/0xc0 [ 33.678613] kfree+0xca/0x250 [ 33.681683] kvfree+0x36/0x60 [ 33.684754] free_netdev+0x2cf/0x360 [ 33.688431] __tun_chr_ioctl+0x2d24/0x3d60 [ 33.692631] tun_chr_ioctl+0x2a/0x40 [ 33.696311] do_vfs_ioctl+0x1b1/0x1520 [ 33.700162] SyS_ioctl+0x8f/0xc0 [ 33.703491] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 33.708209] [ 33.709806] The buggy address belongs to the object at ffff8801d0cd8300 [ 33.709806] which belongs to the cache kmalloc-16384 of size 16384 [ 33.722774] The buggy address is located 13120 bytes inside of [ 33.722774] 16384-byte region [ffff8801d0cd8300, ffff8801d0cdc300) [ 33.734961] The buggy address belongs to the page: [ 33.739855] page:ffffea0007433600 count:1 mapcount:0 mapping:ffff8801d0cd8300 index:0x0 compound_mapcount: 0 [ 33.749791] flags: 0x200000000008100(slab|head) [ 33.754428] raw: 0200000000008100 ffff8801d0cd8300 0000000000000000 0000000100000001 [ 33.762275] raw: ffffea000762e220 ffffea000743be20 ffff8801dac02200 0000000000000000 [ 33.770120] page dumped because: kasan: bad access detected [ 33.775796] [ 33.777400] Memory state around the buggy address: [ 33.782300] ffff8801d0cdb500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.789624] ffff8801d0cdb580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.796947] >ffff8801d0cdb600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.804269] ^ [ 33.810041] ffff8801d0cdb680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.817365] ffff8801d0cdb700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.824688] ================================================================== [ 33.832013] Disabling lock debugging due to kernel taint [ 33.837427] Kernel panic - not syncing: panic_on_warn set ... [ 33.837427] [ 33.844754] CPU: 0 PID: 3010 Comm: syzkaller464521 Tainted: G B 4.13.0-rc7+ #63 [ 33.853290] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.862608] Call Trace: [ 33.865161] dump_stack+0x194/0x257 [ 33.868767] ? arch_local_irq_restore+0x53/0x53 [ 33.873400] ? kasan_end_report+0x32/0x50 [ 33.877512] ? lock_downgrade+0x990/0x990 [ 33.881626] ? __internal_add_timer+0x210/0x2d0 [ 33.886259] panic+0x1e4/0x417 [ 33.889415] ? __warn+0x1d9/0x1d9 [ 33.892838] ? __internal_add_timer+0x275/0x2d0 [ 33.897471] kasan_end_report+0x50/0x50 [ 33.901409] kasan_report+0x137/0x340 [ 33.905176] __asan_report_store8_noabort+0x17/0x20 [ 33.910155] __internal_add_timer+0x275/0x2d0 [ 33.914613] ? calc_wheel_index+0x200/0x200 [ 33.918907] mod_timer+0x622/0x15b0 [ 33.922500] ? mod_timer_pending+0x14e0/0x14e0 [ 33.927048] ? __lock_is_held+0xb6/0x140 [ 33.931085] ? __lock_is_held+0xb6/0x140 [ 33.935115] ? lockdep_init_map+0xe4/0x650 [ 33.939323] ? init_timer_key+0x126/0x3b0 [ 33.943437] ? try_to_del_timer_sync+0x120/0x120 [ 33.948158] ? round_jiffies_up+0xce/0x100 [ 33.952358] ? __round_jiffies_up_relative+0x150/0x150 [ 33.957598] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 33.962493] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 33.967998] __tun_chr_ioctl+0x1b20/0x3d60 [ 33.972202] ? tun_select_queue+0x580/0x580 [ 33.976490] ? check_noncircular+0x20/0x20 [ 33.980705] ? get_unused_fd_flags+0x190/0x190 [ 33.985255] ? __handle_mm_fault+0x577/0x3860 [ 33.989716] ? check_noncircular+0x20/0x20 [ 33.993918] ? check_noncircular+0x20/0x20 [ 33.998115] ? __pmd_alloc+0x4e0/0x4e0 [ 34.001975] ? check_same_owner+0x320/0x320 [ 34.006269] ? handle_mm_fault+0x23e/0x860 [ 34.010470] ? tun_chr_compat_ioctl+0x30/0x30 [ 34.014932] tun_chr_ioctl+0x2a/0x40 [ 34.018610] ? tun_chr_ioctl+0x2a/0x40 [ 34.022463] do_vfs_ioctl+0x1b1/0x1520 [ 34.026316] ? ioctl_preallocate+0x2b0/0x2b0 [ 34.030704] ? selinux_capable+0x40/0x40 [ 34.034738] ? __handle_mm_fault+0x3860/0x3860 [ 34.039295] ? security_file_ioctl+0x7d/0xb0 [ 34.043667] ? security_file_ioctl+0x89/0xb0 [ 34.048044] SyS_ioctl+0x8f/0xc0 [ 34.051378] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 34.056097] RIP: 0033:0x443dd9 [ 34.059260] RSP: 002b:00007fff2fe31ea8 EFLAGS: 00000207 ORIG_RAX: 0000000000000010 [ 34.066939] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443dd9 [ 34.074173] RDX: 0000000020074000 RSI: 00000000400454ca RDI: 0000000000000006 [ 34.081407] RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 [ 34.088642] R10: 0000000000000000 R11: 0000000000000207 R12: e756701d2c7e9737 [ 34.095888] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 34.103176] Dumping ftrace buffer: [ 34.106680] (ftrace buffer empty) [ 34.111372] Kernel Offset: disabled [ 34.114965] Rebooting in 86400 seconds..