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-6,10.128.0.46' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 40.076296] ================================================================== [ 40.077403] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 40.078325] Write of size 8 at addr ffff8801d2fe3600 by task syzkaller644368/2990 [ 40.079321] [ 40.079622] CPU: 0 PID: 2990 Comm: syzkaller644368 Not tainted 4.14.0-rc5+ #141 [ 40.080608] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.081837] Call Trace: [ 40.082197] dump_stack+0x194/0x257 [ 40.082699] ? arch_local_irq_restore+0x53/0x53 [ 40.083319] ? show_regs_print_info+0x65/0x65 [ 40.083935] ? __kernel_text_address+0xd/0x40 [ 40.084534] ? __internal_add_timer+0x275/0x2d0 [ 40.085173] print_address_description+0x73/0x250 [ 40.085828] ? __internal_add_timer+0x275/0x2d0 [ 40.086489] kasan_report+0x25b/0x340 [ 40.087004] __asan_report_store8_noabort+0x17/0x20 [ 40.087672] __internal_add_timer+0x275/0x2d0 [ 40.088274] ? calc_wheel_index+0x200/0x200 [ 40.088860] mod_timer+0x622/0x15b0 [ 40.089360] ? mod_timer_pending+0x14e0/0x14e0 [ 40.089971] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 40.090638] ? trace_hardirqs_on+0xd/0x10 [ 40.091206] ? _crng_backtrack_protect+0xd9/0x130 [ 40.091862] ? __lock_is_held+0xb6/0x140 [ 40.092428] ? __lockdep_init_map+0xe4/0x650 [ 40.093035] ? lockdep_init_map+0x9/0x10 [ 40.093676] ? init_timer_key+0x126/0x3b0 [ 40.094257] ? try_to_del_timer_sync+0x120/0x120 [ 40.094919] ? round_jiffies_up+0xce/0x100 [ 40.095496] ? __round_jiffies_up_relative+0x150/0x150 [ 40.096220] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 40.099951] __tun_chr_ioctl+0x1b17/0x3d20 [ 40.104163] ? tun_chr_read_iter+0x1e0/0x1e0 [ 40.108538] ? find_held_lock+0x35/0x1d0 [ 40.112576] ? __do_page_fault+0x64c/0xd60 [ 40.116778] ? lock_downgrade+0x990/0x990 [ 40.120901] ? handle_mm_fault+0x410/0x8d0 [ 40.125115] ? check_same_owner+0x320/0x320 [ 40.129409] ? up_read+0x1a/0x40 [ 40.132742] ? __do_page_fault+0x3d6/0xd60 [ 40.136944] ? tun_chr_compat_ioctl+0x30/0x30 [ 40.141405] tun_chr_ioctl+0x2a/0x40 [ 40.145081] ? tun_chr_ioctl+0x2a/0x40 [ 40.148936] do_vfs_ioctl+0x1b1/0x1520 [ 40.152793] ? ioctl_preallocate+0x2b0/0x2b0 [ 40.157168] ? selinux_capable+0x40/0x40 [ 40.161198] ? putname+0xf3/0x130 [ 40.164620] ? do_sys_open+0x320/0x6d0 [ 40.168486] ? security_file_ioctl+0x89/0xb0 [ 40.172862] SyS_ioctl+0x8f/0xc0 [ 40.176199] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 40.180918] RIP: 0033:0x443d69 [ 40.184072] RSP: 002b:00007ffe31dac2c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 40.191744] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443d69 [ 40.198978] RDX: 0000000020511fd8 RSI: 00000000400454ca RDI: 0000000000000004 [ 40.206213] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 40.213460] R10: 0000000000000000 R11: 0000000000000202 R12: ff4f0caabc6b2b7e [ 40.220693] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 40.227945] [ 40.229537] Allocated by task 2990: [ 40.233131] save_stack_trace+0x16/0x20 [ 40.237069] save_stack+0x43/0xd0 [ 40.240485] kasan_kmalloc+0xad/0xe0 [ 40.244160] __kmalloc_node+0x47/0x70 [ 40.247924] kvmalloc_node+0x64/0xd0 [ 40.251601] alloc_netdev_mqs+0x16e/0xed0 [ 40.255713] __tun_chr_ioctl+0x12b2/0x3d20 [ 40.259911] tun_chr_ioctl+0x2a/0x40 [ 40.263588] do_vfs_ioctl+0x1b1/0x1520 [ 40.267437] SyS_ioctl+0x8f/0xc0 [ 40.270771] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 40.275487] [ 40.277088] Freed by task 2990: [ 40.280338] save_stack_trace+0x16/0x20 [ 40.284276] save_stack+0x43/0xd0 [ 40.287691] kasan_slab_free+0x71/0xc0 [ 40.291542] kfree+0xca/0x250 [ 40.294611] kvfree+0x36/0x60 [ 40.297681] free_netdev+0x2cf/0x360 [ 40.301358] __tun_chr_ioctl+0x2cea/0x3d20 [ 40.305555] tun_chr_ioctl+0x2a/0x40 [ 40.309230] do_vfs_ioctl+0x1b1/0x1520 [ 40.313081] SyS_ioctl+0x8f/0xc0 [ 40.316413] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 40.321128] [ 40.322721] The buggy address belongs to the object at ffff8801d2fe02c0 [ 40.322721] which belongs to the cache kmalloc-16384 of size 16384 [ 40.335968] The buggy address is located 13120 bytes inside of [ 40.335968] 16384-byte region [ffff8801d2fe02c0, ffff8801d2fe42c0) [ 40.348151] The buggy address belongs to the page: [ 40.353048] page:ffffea00074bf800 count:1 mapcount:0 mapping:ffff8801d2fe02c0 index:0x0 compound_mapcount: 0 [ 40.362985] flags: 0x200000000008100(slab|head) [ 40.367619] raw: 0200000000008100 ffff8801d2fe02c0 0000000000000000 0000000100000001 [ 40.375465] raw: ffffea000765b620 ffffea00074a4c20 ffff8801dac02200 0000000000000000 [ 40.383311] page dumped because: kasan: bad access detected [ 40.388985] [ 40.390578] Memory state around the buggy address: [ 40.395470] ffff8801d2fe3500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.402791] ffff8801d2fe3580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.410115] >ffff8801d2fe3600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.417441] ^ [ 40.420772] ffff8801d2fe3680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.428098] ffff8801d2fe3700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 40.435419] ================================================================== [ 40.442739] Disabling lock debugging due to kernel taint [ 40.448153] Kernel panic - not syncing: panic_on_warn set ... [ 40.448153] [ 40.455477] CPU: 0 PID: 2990 Comm: syzkaller644368 Tainted: G B 4.14.0-rc5+ #141 [ 40.464100] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 40.473416] Call Trace: [ 40.475968] dump_stack+0x194/0x257 [ 40.479564] ? arch_local_irq_restore+0x53/0x53 [ 40.484197] ? kasan_end_report+0x32/0x50 [ 40.488313] ? lock_downgrade+0x990/0x990 [ 40.492430] ? __internal_add_timer+0x1f0/0x2d0 [ 40.497065] panic+0x1e4/0x417 [ 40.500224] ? __warn+0x1d9/0x1d9 [ 40.503646] ? __internal_add_timer+0x275/0x2d0 [ 40.508277] kasan_end_report+0x50/0x50 [ 40.512214] kasan_report+0x144/0x340 [ 40.515980] __asan_report_store8_noabort+0x17/0x20 [ 40.520959] __internal_add_timer+0x275/0x2d0 [ 40.525416] ? calc_wheel_index+0x200/0x200 [ 40.529709] mod_timer+0x622/0x15b0 [ 40.533305] ? mod_timer_pending+0x14e0/0x14e0 [ 40.537860] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 40.542842] ? trace_hardirqs_on+0xd/0x10 [ 40.546954] ? _crng_backtrack_protect+0xd9/0x130 [ 40.551761] ? __lock_is_held+0xb6/0x140 [ 40.555789] ? __lockdep_init_map+0xe4/0x650 [ 40.560168] ? lockdep_init_map+0x9/0x10 [ 40.564193] ? init_timer_key+0x126/0x3b0 [ 40.568304] ? try_to_del_timer_sync+0x120/0x120 [ 40.573023] ? round_jiffies_up+0xce/0x100 [ 40.577220] ? __round_jiffies_up_relative+0x150/0x150 [ 40.582460] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 40.587358] __tun_chr_ioctl+0x1b17/0x3d20 [ 40.591562] ? tun_chr_read_iter+0x1e0/0x1e0 [ 40.595935] ? find_held_lock+0x35/0x1d0 [ 40.599963] ? __do_page_fault+0x64c/0xd60 [ 40.604173] ? lock_downgrade+0x990/0x990 [ 40.608292] ? handle_mm_fault+0x410/0x8d0 [ 40.612500] ? check_same_owner+0x320/0x320 [ 40.616782] ? up_read+0x1a/0x40 [ 40.620113] ? __do_page_fault+0x3d6/0xd60 [ 40.624311] ? tun_chr_compat_ioctl+0x30/0x30 [ 40.628768] tun_chr_ioctl+0x2a/0x40 [ 40.632444] ? tun_chr_ioctl+0x2a/0x40 [ 40.636297] do_vfs_ioctl+0x1b1/0x1520 [ 40.640149] ? ioctl_preallocate+0x2b0/0x2b0 [ 40.644523] ? selinux_capable+0x40/0x40 [ 40.648547] ? putname+0xf3/0x130 [ 40.651966] ? do_sys_open+0x320/0x6d0 [ 40.655822] ? security_file_ioctl+0x89/0xb0 [ 40.660194] SyS_ioctl+0x8f/0xc0 [ 40.663529] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 40.668246] RIP: 0033:0x443d69 [ 40.671400] RSP: 002b:00007ffe31dac2c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 40.679075] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443d69 [ 40.686311] RDX: 0000000020511fd8 RSI: 00000000400454ca RDI: 0000000000000004 [ 40.693543] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 40.700777] R10: 0000000000000000 R11: 0000000000000202 R12: ff4f0caabc6b2b7e [ 40.708012] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 40.715294] Dumping ftrace buffer: [ 40.718797] (ftrace buffer empty) [ 40.722471] Kernel Offset: disabled [ 40.726064] Rebooting in 86400 seconds..