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 'ci-upstream-kasan-gce-5,10.128.0.36' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 33.574411] ================================================================== [ 33.575491] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 33.576444] Write of size 8 at addr ffff8801d21ab500 by task syzkaller828369/2986 [ 33.577442] [ 33.577676] CPU: 1 PID: 2986 Comm: syzkaller828369 Not tainted 4.14.0-rc5+ #142 [ 33.578694] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.579959] Call Trace: [ 33.580316] dump_stack+0x194/0x257 [ 33.580809] ? arch_local_irq_restore+0x53/0x53 [ 33.581430] ? show_regs_print_info+0x65/0x65 [ 33.582034] ? __kernel_text_address+0xd/0x40 [ 33.582634] ? __internal_add_timer+0x275/0x2d0 [ 33.583259] print_address_description+0x73/0x250 [ 33.583906] ? __internal_add_timer+0x275/0x2d0 [ 33.584529] kasan_report+0x25b/0x340 [ 33.585044] __asan_report_store8_noabort+0x17/0x20 [ 33.585709] __internal_add_timer+0x275/0x2d0 [ 33.586310] ? calc_wheel_index+0x200/0x200 [ 33.586898] mod_timer+0x622/0x15b0 [ 33.587395] ? mod_timer_pending+0x14e0/0x14e0 [ 33.588007] ? __lock_is_held+0xb6/0x140 [ 33.588576] ? __lock_is_held+0xb6/0x140 [ 33.589125] ? __lockdep_init_map+0xe4/0x650 [ 33.589747] ? lockdep_init_map+0x9/0x10 [ 33.590305] ? init_timer_key+0x126/0x3b0 [ 33.590863] ? try_to_del_timer_sync+0x120/0x120 [ 33.591509] ? round_jiffies_up+0xce/0x100 [ 33.592076] ? __round_jiffies_up_relative+0x150/0x150 [ 33.592782] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 33.593439] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 33.594191] __tun_chr_ioctl+0x1b17/0x3d20 [ 33.594766] ? tun_chr_read_iter+0x1e0/0x1e0 [ 33.599139] ? find_held_lock+0x35/0x1d0 [ 33.603174] ? __do_page_fault+0x64c/0xd60 [ 33.607380] ? lock_downgrade+0x990/0x990 [ 33.611504] ? handle_mm_fault+0x410/0x8d0 [ 33.615719] ? check_same_owner+0x320/0x320 [ 33.620004] ? up_read+0x1a/0x40 [ 33.623337] ? __do_page_fault+0x3d6/0xd60 [ 33.627542] ? tun_chr_compat_ioctl+0x30/0x30 [ 33.632001] tun_chr_ioctl+0x2a/0x40 [ 33.635679] ? tun_chr_ioctl+0x2a/0x40 [ 33.639536] do_vfs_ioctl+0x1b1/0x1520 [ 33.643396] ? ioctl_preallocate+0x2b0/0x2b0 [ 33.647775] ? selinux_capable+0x40/0x40 [ 33.651806] ? putname+0xf3/0x130 [ 33.655232] ? do_sys_open+0x320/0x6d0 [ 33.659094] ? security_file_ioctl+0x89/0xb0 [ 33.663473] SyS_ioctl+0x8f/0xc0 [ 33.666823] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 33.671545] RIP: 0033:0x443dc9 [ 33.674701] RSP: 002b:00007ffd8c4adcf8 EFLAGS: 00000207 ORIG_RAX: 0000000000000010 [ 33.682375] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443dc9 [ 33.689612] RDX: 0000000020927fd8 RSI: 00000000400454ca RDI: 0000000000000006 [ 33.696848] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 33.704086] R10: 0000000000000000 R11: 0000000000000207 R12: daa35d18b56625c2 [ 33.711323] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 33.718575] [ 33.720172] Allocated by task 2986: [ 33.723769] save_stack_trace+0x16/0x20 [ 33.727710] save_stack+0x43/0xd0 [ 33.731128] kasan_kmalloc+0xad/0xe0 [ 33.734807] __kmalloc_node+0x47/0x70 [ 33.738574] kvmalloc_node+0x64/0xd0 [ 33.742258] alloc_netdev_mqs+0x16e/0xed0 [ 33.746374] __tun_chr_ioctl+0x12b2/0x3d20 [ 33.750574] tun_chr_ioctl+0x2a/0x40 [ 33.754253] do_vfs_ioctl+0x1b1/0x1520 [ 33.758104] SyS_ioctl+0x8f/0xc0 [ 33.761436] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 33.766155] [ 33.767749] Freed by task 2986: [ 33.770993] save_stack_trace+0x16/0x20 [ 33.774930] save_stack+0x43/0xd0 [ 33.778349] kasan_slab_free+0x71/0xc0 [ 33.782201] kfree+0xca/0x250 [ 33.785273] kvfree+0x36/0x60 [ 33.788347] free_netdev+0x2cf/0x360 [ 33.792023] __tun_chr_ioctl+0x2cea/0x3d20 [ 33.796221] tun_chr_ioctl+0x2a/0x40 [ 33.799900] do_vfs_ioctl+0x1b1/0x1520 [ 33.803750] SyS_ioctl+0x8f/0xc0 [ 33.807081] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 33.811799] [ 33.813393] The buggy address belongs to the object at ffff8801d21a81c0 [ 33.813393] which belongs to the cache kmalloc-16384 of size 16384 [ 33.826358] The buggy address is located 13120 bytes inside of [ 33.826358] 16384-byte region [ffff8801d21a81c0, ffff8801d21ac1c0) [ 33.838544] The buggy address belongs to the page: [ 33.843443] page:ffffea0007486a00 count:1 mapcount:0 mapping:ffff8801d21a81c0 index:0x0 compound_mapcount: 0 [ 33.853376] flags: 0x200000000008100(slab|head) [ 33.858029] raw: 0200000000008100 ffff8801d21a81c0 0000000000000000 0000000100000001 [ 33.865876] raw: ffffea0007654e20 ffffea00074a8a20 ffff8801dac02200 0000000000000000 [ 33.873726] page dumped because: kasan: bad access detected [ 33.879398] [ 33.880991] Memory state around the buggy address: [ 33.885883] ffff8801d21ab400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.893207] ffff8801d21ab480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.900529] >ffff8801d21ab500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.907849] ^ [ 33.911180] ffff8801d21ab580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.918505] ffff8801d21ab600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.925826] ================================================================== [ 33.933146] Disabling lock debugging due to kernel taint [ 33.938645] Kernel panic - not syncing: panic_on_warn set ... [ 33.938645] [ 33.945971] CPU: 1 PID: 2986 Comm: syzkaller828369 Tainted: G B 4.14.0-rc5+ #142 [ 33.954596] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.963913] Call Trace: [ 33.966469] dump_stack+0x194/0x257 [ 33.970062] ? arch_local_irq_restore+0x53/0x53 [ 33.974695] ? kasan_end_report+0x32/0x50 [ 33.978808] ? lock_downgrade+0x990/0x990 [ 33.982925] ? __internal_add_timer+0x1f0/0x2d0 [ 33.987561] panic+0x1e4/0x417 [ 33.990717] ? __warn+0x1d9/0x1d9 [ 33.994140] ? __internal_add_timer+0x275/0x2d0 [ 33.998775] kasan_end_report+0x50/0x50 [ 34.003033] kasan_report+0x144/0x340 [ 34.006803] __asan_report_store8_noabort+0x17/0x20 [ 34.011786] __internal_add_timer+0x275/0x2d0 [ 34.016248] ? calc_wheel_index+0x200/0x200 [ 34.020542] mod_timer+0x622/0x15b0 [ 34.024140] ? mod_timer_pending+0x14e0/0x14e0 [ 34.028687] ? __lock_is_held+0xb6/0x140 [ 34.032737] ? __lock_is_held+0xb6/0x140 [ 34.036765] ? __lockdep_init_map+0xe4/0x650 [ 34.041140] ? lockdep_init_map+0x9/0x10 [ 34.045165] ? init_timer_key+0x126/0x3b0 [ 34.049279] ? try_to_del_timer_sync+0x120/0x120 [ 34.054002] ? round_jiffies_up+0xce/0x100 [ 34.058203] ? __round_jiffies_up_relative+0x150/0x150 [ 34.063444] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 34.068342] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 34.073847] __tun_chr_ioctl+0x1b17/0x3d20 [ 34.078052] ? tun_chr_read_iter+0x1e0/0x1e0 [ 34.082423] ? find_held_lock+0x35/0x1d0 [ 34.086455] ? __do_page_fault+0x64c/0xd60 [ 34.090654] ? lock_downgrade+0x990/0x990 [ 34.094771] ? handle_mm_fault+0x410/0x8d0 [ 34.098980] ? check_same_owner+0x320/0x320 [ 34.103273] ? up_read+0x1a/0x40 [ 34.106604] ? __do_page_fault+0x3d6/0xd60 [ 34.110803] ? tun_chr_compat_ioctl+0x30/0x30 [ 34.115266] tun_chr_ioctl+0x2a/0x40 [ 34.118944] ? tun_chr_ioctl+0x2a/0x40 [ 34.122799] do_vfs_ioctl+0x1b1/0x1520 [ 34.126654] ? ioctl_preallocate+0x2b0/0x2b0 [ 34.131036] ? selinux_capable+0x40/0x40 [ 34.135064] ? putname+0xf3/0x130 [ 34.138487] ? do_sys_open+0x320/0x6d0 [ 34.142347] ? security_file_ioctl+0x89/0xb0 [ 34.146724] SyS_ioctl+0x8f/0xc0 [ 34.150062] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 34.154780] RIP: 0033:0x443dc9 [ 34.157938] RSP: 002b:00007ffd8c4adcf8 EFLAGS: 00000207 ORIG_RAX: 0000000000000010 [ 34.165610] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443dc9 [ 34.172845] RDX: 0000000020927fd8 RSI: 00000000400454ca RDI: 0000000000000006 [ 34.180081] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 34.187319] R10: 0000000000000000 R11: 0000000000000207 R12: daa35d18b56625c2 [ 34.194553] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 34.202140] Dumping ftrace buffer: [ 34.205643] (ftrace buffer empty) [ 34.209320] Kernel Offset: disabled [ 34.212916] Rebooting in 86400 seconds..