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-8,10.128.0.34' (ECDSA) to the list of known hosts. net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz0.router_solicitations = 0 executing program syzkaller login: [ 51.358472] ================================================================== [ 51.359586] BUG: KASAN: use-after-free in detach_if_pending+0x557/0x610 [ 51.360472] Write of size 8 at addr ffff8801d22eb6b8 by task syzkaller708097/2978 [ 51.361467] [ 51.361697] CPU: 0 PID: 2978 Comm: syzkaller708097 Not tainted 4.14.0-rc5+ #134 [ 51.362672] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.363909] Call Trace: [ 51.364266] dump_stack+0x194/0x257 [ 51.364762] ? arch_local_irq_restore+0x53/0x53 [ 51.365385] ? show_regs_print_info+0x65/0x65 [ 51.365986] ? lock_timer_base+0x1a3/0x2b0 [ 51.366555] ? detach_if_pending+0x557/0x610 [ 51.367147] print_address_description+0x73/0x250 [ 51.367791] ? detach_if_pending+0x557/0x610 [ 51.368383] kasan_report+0x25b/0x340 [ 51.368898] __asan_report_store8_noabort+0x17/0x20 [ 51.369564] detach_if_pending+0x557/0x610 [ 51.370134] ? trace_raw_output_tick_stop+0x130/0x130 [ 51.370825] ? _raw_spin_lock_irqsave+0x9e/0xc0 [ 51.371445] ? lock_timer_base+0x1a3/0x2b0 [ 51.372011] ? lock_timer_base+0x1eb/0x2b0 [ 51.372580] ? __internal_add_timer+0x2d0/0x2d0 [ 51.373202] ? lock_downgrade+0x990/0x990 [ 51.373790] ? trace_hardirqs_on+0xd/0x10 [ 51.374353] try_to_del_timer_sync+0xa2/0x120 [ 51.374952] ? del_timer+0x130/0x130 [ 51.375457] ? del_timer_sync+0xeb/0x240 [ 51.376007] del_timer_sync+0x18a/0x240 [ 51.376543] tun_free_netdev+0x105/0x1b0 [ 51.377086] ? tun_xdp+0x410/0x410 [ 51.377560] ? cpumask_next+0x24/0x30 [ 51.378071] ? netdev_refcnt_read+0xed/0x150 [ 51.378981] ? tun_xdp+0x410/0x410 [ 51.382489] netdev_run_todo+0x870/0xca0 [ 51.386517] ? do_group_exit+0x149/0x400 [ 51.390546] ? mark_held_locks+0xaf/0x100 [ 51.394663] ? register_netdev+0x30/0x30 [ 51.398697] ? find_held_lock+0x35/0x1d0 [ 51.402735] ? lock_downgrade+0x990/0x990 [ 51.406946] ? refcount_sub_and_test+0x115/0x1b0 [ 51.411668] ? refcount_inc+0x50/0x50 [ 51.415434] ? refcount_inc+0x50/0x50 [ 51.419207] ? sk_destruct+0x4c/0x80 [ 51.422884] ? __sk_free+0x5c/0x230 [ 51.426478] ? sk_free+0x2f/0x40 [ 51.429809] ? __tun_detach+0x176/0x1390 [ 51.433847] ? tun_attach+0xfa0/0xfa0 [ 51.437621] ? locks_remove_file+0x3fa/0x5a0 [ 51.441997] ? fcntl_setlk+0x10c0/0x10c0 [ 51.446026] ? __fsnotify_parent+0xb4/0x3a0 [ 51.450315] ? fsnotify+0x1af0/0x1af0 [ 51.454086] ? __tun_detach+0x1390/0x1390 [ 51.458202] rtnl_unlock+0xe/0x10 [ 51.461621] tun_chr_close+0x49/0x60 [ 51.465300] __fput+0x327/0x7e0 [ 51.468552] ? fput+0x140/0x140 [ 51.471798] ? check_same_owner+0x320/0x320 [ 51.476092] ____fput+0x15/0x20 [ 51.479340] task_work_run+0x199/0x270 [ 51.483197] ? task_work_cancel+0x210/0x210 [ 51.487484] ? free_nsproxy+0x185/0x1f0 [ 51.491426] ? switch_task_namespaces+0xa2/0xc0 [ 51.496065] do_exit+0x9b5/0x1ad0 [ 51.499484] ? kvfree+0x3b/0x60 [ 51.502731] ? mm_update_next_owner+0x930/0x930 [ 51.507364] ? rtnl_unlock+0xe/0x10 [ 51.510956] ? __tun_chr_ioctl+0x27a/0x3d20 [ 51.515255] ? tun_chr_read_iter+0x1e0/0x1e0 [ 51.519628] ? find_held_lock+0x35/0x1d0 [ 51.523664] ? __do_page_fault+0x64c/0xd60 [ 51.527866] ? lock_downgrade+0x990/0x990 [ 51.531989] ? handle_mm_fault+0x410/0x8d0 [ 51.536205] ? check_same_owner+0x320/0x320 [ 51.540490] ? up_read+0x1a/0x40 [ 51.543820] ? __do_page_fault+0x3d6/0xd60 [ 51.548022] ? tun_chr_compat_ioctl+0x30/0x30 [ 51.552479] ? tun_chr_ioctl+0x2a/0x40 [ 51.556328] ? tun_chr_ioctl+0x2a/0x40 [ 51.560184] ? do_vfs_ioctl+0x486/0x1520 [ 51.564215] ? ioctl_preallocate+0x2b0/0x2b0 [ 51.568598] ? selinux_capable+0x40/0x40 [ 51.572627] ? putname+0xf3/0x130 [ 51.576053] do_group_exit+0x149/0x400 [ 51.579909] ? SyS_exit+0x30/0x30 [ 51.583328] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.588312] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.593035] SyS_exit_group+0x1d/0x20 [ 51.596803] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 51.601521] RIP: 0033:0x4452e9 [ 51.604674] RSP: 002b:00007ffc59dde1a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 [ 51.612352] RAX: ffffffffffffffda RBX: 00007ffc59dde1e0 RCX: 00000000004452e9 [ 51.619585] RDX: 00000000004452e9 RSI: 0000000020927fd8 RDI: 0000000000000001 [ 51.626819] RBP: 0000000000000082 R08: 0000000000000000 R09: 00007ffc59dde1e0 [ 51.634051] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000402690 [ 51.641287] R13: 0000000000402720 R14: 0000000000000000 R15: 0000000000000000 [ 51.648537] [ 51.650130] Allocated by task 2978: [ 51.653725] save_stack_trace+0x16/0x20 [ 51.657665] save_stack+0x43/0xd0 [ 51.661081] kasan_kmalloc+0xad/0xe0 [ 51.664758] __kmalloc_node+0x47/0x70 [ 51.668522] kvmalloc_node+0x64/0xd0 [ 51.672200] alloc_netdev_mqs+0x16e/0xed0 [ 51.676310] __tun_chr_ioctl+0x12b2/0x3d20 [ 51.680510] tun_chr_ioctl+0x2a/0x40 [ 51.684187] do_vfs_ioctl+0x1b1/0x1520 [ 51.688038] SyS_ioctl+0x8f/0xc0 [ 51.691370] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 51.696085] [ 51.697678] Freed by task 2978: [ 51.700930] save_stack_trace+0x16/0x20 [ 51.704867] save_stack+0x43/0xd0 [ 51.708283] kasan_slab_free+0x71/0xc0 [ 51.712473] kfree+0xca/0x250 [ 51.715544] kvfree+0x36/0x60 [ 51.718615] free_netdev+0x2cf/0x360 [ 51.722293] __tun_chr_ioctl+0x2cea/0x3d20 [ 51.726490] tun_chr_ioctl+0x2a/0x40 [ 51.730168] do_vfs_ioctl+0x1b1/0x1520 [ 51.734018] SyS_ioctl+0x8f/0xc0 [ 51.737350] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 51.742065] [ 51.743658] The buggy address belongs to the object at ffff8801d22e8380 [ 51.743658] which belongs to the cache kmalloc-16384 of size 16384 [ 51.756626] The buggy address is located 13112 bytes inside of [ 51.756626] 16384-byte region [ffff8801d22e8380, ffff8801d22ec380) [ 51.768808] The buggy address belongs to the page: [ 51.773704] page:ffffea000748ba00 count:1 mapcount:0 mapping:ffff8801d22e8380 index:0x0 compound_mapcount: 0 [ 51.783637] flags: 0x200000000008100(slab|head) [ 51.788277] raw: 0200000000008100 ffff8801d22e8380 0000000000000000 0000000100000001 [ 51.796122] raw: ffffea000744fc20 ffff8801dac01c48 ffff8801dac02200 0000000000000000 [ 51.803963] page dumped because: kasan: bad access detected [ 51.809634] [ 51.811228] Memory state around the buggy address: [ 51.816120] ffff8801d22eb580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.823445] ffff8801d22eb600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.830768] >ffff8801d22eb680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.838088] ^ [ 51.843240] ffff8801d22eb700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.850569] ffff8801d22eb780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.857890] ================================================================== [ 51.865210] Disabling lock debugging due to kernel taint [ 51.870622] Kernel panic - not syncing: panic_on_warn set ... [ 51.870622] [ 51.877947] CPU: 0 PID: 2978 Comm: syzkaller708097 Tainted: G B 4.14.0-rc5+ #134 [ 51.886570] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.895908] Call Trace: [ 51.898463] dump_stack+0x194/0x257 [ 51.902056] ? arch_local_irq_restore+0x53/0x53 [ 51.906687] ? kasan_end_report+0x32/0x50 [ 51.910798] ? lock_downgrade+0x990/0x990 [ 51.914910] ? detach_if_pending+0x510/0x610 [ 51.919282] panic+0x1e4/0x417 [ 51.922436] ? __warn+0x1d9/0x1d9 [ 51.925858] ? detach_if_pending+0x557/0x610 [ 51.930228] kasan_end_report+0x50/0x50 [ 51.934168] kasan_report+0x144/0x340 [ 51.937931] __asan_report_store8_noabort+0x17/0x20 [ 51.942910] detach_if_pending+0x557/0x610 [ 51.947109] ? trace_raw_output_tick_stop+0x130/0x130 [ 51.952261] ? _raw_spin_lock_irqsave+0x9e/0xc0 [ 51.956891] ? lock_timer_base+0x1a3/0x2b0 [ 51.961088] ? lock_timer_base+0x1eb/0x2b0 [ 51.965288] ? __internal_add_timer+0x2d0/0x2d0 [ 51.969923] ? lock_downgrade+0x990/0x990 [ 51.974034] ? trace_hardirqs_on+0xd/0x10 [ 51.978149] try_to_del_timer_sync+0xa2/0x120 [ 51.982606] ? del_timer+0x130/0x130 [ 51.986283] ? del_timer_sync+0xeb/0x240 [ 51.990310] del_timer_sync+0x18a/0x240 [ 51.994250] tun_free_netdev+0x105/0x1b0 [ 51.998274] ? tun_xdp+0x410/0x410 [ 52.001778] ? cpumask_next+0x24/0x30 [ 52.005544] ? netdev_refcnt_read+0xed/0x150 [ 52.009917] ? tun_xdp+0x410/0x410 [ 52.013421] netdev_run_todo+0x870/0xca0 [ 52.017447] ? do_group_exit+0x149/0x400 [ 52.021474] ? mark_held_locks+0xaf/0x100 [ 52.025583] ? register_netdev+0x30/0x30 [ 52.029608] ? find_held_lock+0x35/0x1d0 [ 52.033637] ? lock_downgrade+0x990/0x990 [ 52.037751] ? refcount_sub_and_test+0x115/0x1b0 [ 52.042470] ? refcount_inc+0x50/0x50 [ 52.046238] ? refcount_inc+0x50/0x50 [ 52.050005] ? sk_destruct+0x4c/0x80 [ 52.053680] ? __sk_free+0x5c/0x230 [ 52.057270] ? sk_free+0x2f/0x40 [ 52.060600] ? __tun_detach+0x176/0x1390 [ 52.064627] ? tun_attach+0xfa0/0xfa0 [ 52.068395] ? locks_remove_file+0x3fa/0x5a0 [ 52.072767] ? fcntl_setlk+0x10c0/0x10c0 [ 52.076794] ? __fsnotify_parent+0xb4/0x3a0 [ 52.081079] ? fsnotify+0x1af0/0x1af0 [ 52.084847] ? __tun_detach+0x1390/0x1390 [ 52.088961] rtnl_unlock+0xe/0x10 [ 52.092379] tun_chr_close+0x49/0x60 [ 52.096055] __fput+0x327/0x7e0 [ 52.099300] ? fput+0x140/0x140 [ 52.102543] ? check_same_owner+0x320/0x320 [ 52.106829] ____fput+0x15/0x20 [ 52.110071] task_work_run+0x199/0x270 [ 52.113923] ? task_work_cancel+0x210/0x210 [ 52.118209] ? free_nsproxy+0x185/0x1f0 [ 52.122146] ? switch_task_namespaces+0xa2/0xc0 [ 52.126780] do_exit+0x9b5/0x1ad0 [ 52.130199] ? kvfree+0x3b/0x60 [ 52.133442] ? mm_update_next_owner+0x930/0x930 [ 52.138073] ? rtnl_unlock+0xe/0x10 [ 52.141664] ? __tun_chr_ioctl+0x27a/0x3d20 [ 52.145954] ? tun_chr_read_iter+0x1e0/0x1e0 [ 52.150326] ? find_held_lock+0x35/0x1d0 [ 52.154354] ? __do_page_fault+0x64c/0xd60 [ 52.158552] ? lock_downgrade+0x990/0x990 [ 52.162668] ? handle_mm_fault+0x410/0x8d0 [ 52.166872] ? check_same_owner+0x320/0x320 [ 52.171155] ? up_read+0x1a/0x40 [ 52.174483] ? __do_page_fault+0x3d6/0xd60 [ 52.178682] ? tun_chr_compat_ioctl+0x30/0x30 [ 52.183138] ? tun_chr_ioctl+0x2a/0x40 [ 52.186987] ? tun_chr_ioctl+0x2a/0x40 [ 52.190839] ? do_vfs_ioctl+0x486/0x1520 [ 52.194874] ? ioctl_preallocate+0x2b0/0x2b0 [ 52.199247] ? selinux_capable+0x40/0x40 [ 52.203272] ? putname+0xf3/0x130 [ 52.206692] do_group_exit+0x149/0x400 [ 52.210542] ? SyS_exit+0x30/0x30 [ 52.213959] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 52.218940] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 52.223660] SyS_exit_group+0x1d/0x20 [ 52.227426] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 52.232145] RIP: 0033:0x4452e9 [ 52.235298] RSP: 002b:00007ffc59dde1a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 [ 52.242970] RAX: ffffffffffffffda RBX: 00007ffc59dde1e0 RCX: 00000000004452e9 [ 52.250214] RDX: 00000000004452e9 RSI: 0000000020927fd8 RDI: 0000000000000001 [ 52.257454] RBP: 0000000000000082 R08: 0000000000000000 R09: 00007ffc59dde1e0 [ 52.264689] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000402690 [ 52.271923] R13: 0000000000402720 R14: 0000000000000000 R15: 0000000000000000