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-386-4,10.128.15.210' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 42.672676] ================================================================== [ 42.680087] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 42.687076] Write of size 8 at addr ffff8801ce08b6c8 by task syzkaller156450/2983 [ 42.694666] [ 42.696269] CPU: 1 PID: 2983 Comm: syzkaller156450 Not tainted 4.14.0-rc3+ #30 [ 42.703619] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.712951] Call Trace: [ 42.715516] dump_stack+0x194/0x257 [ 42.719120] ? arch_local_irq_restore+0x53/0x53 [ 42.723770] ? show_regs_print_info+0x65/0x65 [ 42.728241] ? __kernel_text_address+0xd/0x40 [ 42.732709] ? __internal_add_timer+0x275/0x2d0 [ 42.737351] print_address_description+0x73/0x250 [ 42.742164] ? __internal_add_timer+0x275/0x2d0 [ 42.746808] kasan_report+0x25b/0x340 [ 42.750589] __asan_report_store8_noabort+0x17/0x20 [ 42.755578] __internal_add_timer+0x275/0x2d0 [ 42.760044] ? calc_wheel_index+0x200/0x200 [ 42.764347] mod_timer+0x622/0x15b0 [ 42.767954] ? mod_timer_pending+0x14e0/0x14e0 [ 42.772510] ? __lock_is_held+0xbc/0x140 [ 42.776558] ? __lock_is_held+0xbc/0x140 [ 42.780594] ? __lockdep_init_map+0xe4/0x650 [ 42.784976] ? lockdep_init_map+0x3d/0x70 [ 42.789094] ? rcu_read_lock_sched_held+0x108/0x120 [ 42.794082] ? init_timer_key+0x126/0x3b0 [ 42.798202] ? try_to_del_timer_sync+0x120/0x120 [ 42.802930] ? round_jiffies_up+0xce/0x100 [ 42.807137] ? __round_jiffies_up_relative+0x150/0x150 [ 42.812384] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 42.817284] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 42.822803] __tun_chr_ioctl+0x1b23/0x3d20 [ 42.827017] ? tun_chr_read_iter+0x1e0/0x1e0 [ 42.831398] ? find_held_lock+0x39/0x1d0 [ 42.835435] ? __might_sleep+0x95/0x190 [ 42.839395] ? selinux_file_ioctl+0x444/0x690 [ 42.843859] ? __fget_light+0x29d/0x390 [ 42.847807] ? selinux_capable+0x40/0x40 [ 42.851850] ? handle_mm_fault+0x410/0x8d0 [ 42.856061] tun_chr_compat_ioctl+0x29/0x30 [ 42.860351] ? tun_chr_compat_ioctl+0x29/0x30 [ 42.864817] compat_SyS_ioctl+0x1d7/0x3290 [ 42.869020] ? up_read+0x1a/0x40 [ 42.872359] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 42.876739] ? do_ioctl+0x60/0x60 [ 42.880166] ? do_fast_syscall_32+0x158/0xf05 [ 42.884639] ? do_ioctl+0x60/0x60 [ 42.888062] do_fast_syscall_32+0x3f2/0xf05 [ 42.892359] ? do_int80_syscall_32+0x940/0x940 [ 42.896910] ? kasan_check_read+0x11/0x20 [ 42.901030] ? syscall_return_slowpath+0x510/0x510 [ 42.905931] ? SyS_rt_sigaction+0x94/0x1b0 [ 42.910138] ? lockdep_sys_exit+0x47/0xf0 [ 42.914256] ? retint_user+0x18/0x20 [ 42.917948] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.922766] entry_SYSENTER_compat+0x51/0x60 [ 42.927145] RIP: 0023:0xf7fc9c79 [ 42.930481] RSP: 002b:00000000ff9cb30c EFLAGS: 00000282 ORIG_RAX: 0000000000000036 [ 42.938160] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 42.945400] RDX: 0000000020341fd8 RSI: 00000000080ef00c RDI: 000000000000003f [ 42.952640] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 42.959881] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 42.967121] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 42.974378] [ 42.975977] Allocated by task 2983: [ 42.979579] save_stack_trace+0x16/0x20 [ 42.983523] save_stack+0x43/0xd0 [ 42.986947] kasan_kmalloc+0xad/0xe0 [ 42.990630] __kmalloc_node+0x47/0x70 [ 42.994399] kvmalloc_node+0x64/0xd0 [ 42.998083] alloc_netdev_mqs+0x16e/0xed0 [ 43.002202] __tun_chr_ioctl+0x12be/0x3d20 [ 43.006402] tun_chr_compat_ioctl+0x29/0x30 [ 43.010696] compat_SyS_ioctl+0x1d7/0x3290 [ 43.014898] do_fast_syscall_32+0x3f2/0xf05 [ 43.019186] entry_SYSENTER_compat+0x51/0x60 [ 43.023559] [ 43.025156] Freed by task 2983: [ 43.028403] save_stack_trace+0x16/0x20 [ 43.032343] save_stack+0x43/0xd0 [ 43.035764] kasan_slab_free+0x71/0xc0 [ 43.039619] kfree+0xca/0x250 [ 43.042701] kvfree+0x36/0x60 [ 43.045776] free_netdev+0x2cf/0x360 [ 43.049458] __tun_chr_ioctl+0x2cf6/0x3d20 [ 43.053661] tun_chr_compat_ioctl+0x29/0x30 [ 43.057949] compat_SyS_ioctl+0x1d7/0x3290 [ 43.062152] do_fast_syscall_32+0x3f2/0xf05 [ 43.066444] entry_SYSENTER_compat+0x51/0x60 [ 43.070817] [ 43.072413] The buggy address belongs to the object at ffff8801ce0882c0 [ 43.072413] which belongs to the cache kmalloc-16384 of size 16384 [ 43.085383] The buggy address is located 13320 bytes inside of [ 43.085383] 16384-byte region [ffff8801ce0882c0, ffff8801ce08c2c0) [ 43.097573] The buggy address belongs to the page: [ 43.102470] page:ffffea0007382200 count:1 mapcount:0 mapping:ffff8801ce0882c0 index:0x0 compound_mapcount: 0 [ 43.112419] flags: 0x200000000008100(slab|head) [ 43.117057] raw: 0200000000008100 ffff8801ce0882c0 0000000000000000 0000000100000001 [ 43.124907] raw: ffffea0007542020 ffffea0007381420 ffff8801dac02200 0000000000000000 [ 43.132754] page dumped because: kasan: bad access detected [ 43.138431] [ 43.140028] Memory state around the buggy address: [ 43.144924] ffff8801ce08b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 43.152251] ffff8801ce08b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 43.159580] >ffff8801ce08b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 43.166906] ^ [ 43.172585] ffff8801ce08b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 43.179915] ffff8801ce08b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 43.187327] ================================================================== [ 43.194652] Disabling lock debugging due to kernel taint [ 43.200063] Kernel panic - not syncing: panic_on_warn set ... [ 43.200063] [ 43.207388] CPU: 1 PID: 2983 Comm: syzkaller156450 Tainted: G B 4.14.0-rc3+ #30 [ 43.215923] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 43.225241] Call Trace: [ 43.227797] dump_stack+0x194/0x257 [ 43.231391] ? arch_local_irq_restore+0x53/0x53 [ 43.236024] ? vprintk_default+0x28/0x30 [ 43.240051] ? __internal_add_timer+0x1f0/0x2d0 [ 43.244774] panic+0x1e4/0x417 [ 43.247930] ? __warn+0x1d9/0x1d9 [ 43.251352] ? __internal_add_timer+0x275/0x2d0 [ 43.255984] kasan_end_report+0x50/0x50 [ 43.259922] kasan_report+0x144/0x340 [ 43.263689] __asan_report_store8_noabort+0x17/0x20 [ 43.268669] __internal_add_timer+0x275/0x2d0 [ 43.273129] ? calc_wheel_index+0x200/0x200 [ 43.277421] mod_timer+0x622/0x15b0 [ 43.281018] ? mod_timer_pending+0x14e0/0x14e0 [ 43.285564] ? __lock_is_held+0xbc/0x140 [ 43.289596] ? __lock_is_held+0xbc/0x140 [ 43.293623] ? __lockdep_init_map+0xe4/0x650 [ 43.297995] ? lockdep_init_map+0x3d/0x70 [ 43.302110] ? rcu_read_lock_sched_held+0x108/0x120 [ 43.307090] ? init_timer_key+0x126/0x3b0 [ 43.311201] ? try_to_del_timer_sync+0x120/0x120 [ 43.315921] ? round_jiffies_up+0xce/0x100 [ 43.320119] ? __round_jiffies_up_relative+0x150/0x150 [ 43.325358] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 43.330251] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 43.335757] __tun_chr_ioctl+0x1b23/0x3d20 [ 43.339963] ? tun_chr_read_iter+0x1e0/0x1e0 [ 43.344334] ? find_held_lock+0x39/0x1d0 [ 43.348361] ? __might_sleep+0x95/0x190 [ 43.352304] ? selinux_file_ioctl+0x444/0x690 [ 43.356762] ? __fget_light+0x29d/0x390 [ 43.360700] ? selinux_capable+0x40/0x40 [ 43.364731] ? handle_mm_fault+0x410/0x8d0 [ 43.368933] tun_chr_compat_ioctl+0x29/0x30 [ 43.373217] ? tun_chr_compat_ioctl+0x29/0x30 [ 43.377678] compat_SyS_ioctl+0x1d7/0x3290 [ 43.381886] ? up_read+0x1a/0x40 [ 43.385217] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 43.389605] ? do_ioctl+0x60/0x60 [ 43.393026] ? do_fast_syscall_32+0x158/0xf05 [ 43.397487] ? do_ioctl+0x60/0x60 [ 43.400906] do_fast_syscall_32+0x3f2/0xf05 [ 43.405196] ? do_int80_syscall_32+0x940/0x940 [ 43.409742] ? kasan_check_read+0x11/0x20 [ 43.413856] ? syscall_return_slowpath+0x510/0x510 [ 43.418750] ? SyS_rt_sigaction+0x94/0x1b0 [ 43.422950] ? lockdep_sys_exit+0x47/0xf0 [ 43.427061] ? retint_user+0x18/0x20 [ 43.430743] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 43.435555] entry_SYSENTER_compat+0x51/0x60 [ 43.439925] RIP: 0023:0xf7fc9c79 [ 43.443252] RSP: 002b:00000000ff9cb30c EFLAGS: 00000282 ORIG_RAX: 0000000000000036 [ 43.450938] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 43.458178] RDX: 0000000020341fd8 RSI: 00000000080ef00c RDI: 000000000000003f [ 43.465414] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 43.472650] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 43.479884] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 43.487165] Dumping ftrace buffer: [ 43.490672] (ftrace buffer empty) [ 43.494348] Kernel Offset: disabled [ 43.497942] Rebooting in 86400 seconds..