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-386-3,10.128.0.49' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 25.056570] ================================================================== [ 25.064035] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 25.071023] Write of size 8 at addr ffff8801ce763688 by task syzkaller183041/2982 [ 25.078612] [ 25.080216] CPU: 0 PID: 2982 Comm: syzkaller183041 Not tainted 4.14.0-rc2+ #14 [ 25.087543] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.096874] Call Trace: [ 25.099441] dump_stack+0x194/0x257 [ 25.103044] ? arch_local_irq_restore+0x53/0x53 [ 25.107685] ? show_regs_print_info+0x65/0x65 [ 25.112158] ? __internal_add_timer+0x275/0x2d0 [ 25.116801] print_address_description+0x73/0x250 [ 25.121616] ? __internal_add_timer+0x275/0x2d0 [ 25.126257] kasan_report+0x25b/0x340 [ 25.130035] __asan_report_store8_noabort+0x17/0x20 [ 25.135021] __internal_add_timer+0x275/0x2d0 [ 25.139491] ? calc_wheel_index+0x200/0x200 [ 25.143800] mod_timer+0x622/0x15b0 [ 25.147409] ? mod_timer_pending+0x14e0/0x14e0 [ 25.151964] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 25.156958] ? trace_hardirqs_on+0xd/0x10 [ 25.161185] ? _crng_backtrack_protect+0xd9/0x130 [ 25.166011] ? __lock_is_held+0xbc/0x140 [ 25.170048] ? __lockdep_init_map+0xe4/0x650 [ 25.174433] ? lockdep_init_map+0x3d/0x70 [ 25.178563] ? rcu_read_lock_sched_held+0x108/0x120 [ 25.183551] ? init_timer_key+0x126/0x3b0 [ 25.187674] ? try_to_del_timer_sync+0x120/0x120 [ 25.192405] ? round_jiffies_up+0xce/0x100 [ 25.196611] ? __round_jiffies_up_relative+0x150/0x150 [ 25.201859] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 25.206770] __tun_chr_ioctl+0x1b23/0x3d20 [ 25.210987] ? tun_chr_read_iter+0x1e0/0x1e0 [ 25.215370] ? __pmd_alloc+0x4e0/0x4e0 [ 25.219237] ? __might_sleep+0x95/0x190 [ 25.223197] ? selinux_file_ioctl+0x444/0x690 [ 25.227666] ? __fget_light+0x29d/0x390 [ 25.231615] ? selinux_capable+0x40/0x40 [ 25.235671] tun_chr_compat_ioctl+0x29/0x30 [ 25.239965] ? tun_chr_compat_ioctl+0x29/0x30 [ 25.244436] compat_SyS_ioctl+0x1d7/0x3290 [ 25.248642] ? __handle_mm_fault+0x39c0/0x39c0 [ 25.253198] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 25.257589] ? do_ioctl+0x60/0x60 [ 25.261019] ? do_fast_syscall_32+0x158/0xf05 [ 25.265491] ? do_ioctl+0x60/0x60 [ 25.268917] do_fast_syscall_32+0x3f2/0xf05 [ 25.273218] ? do_int80_syscall_32+0x940/0x940 [ 25.277776] ? kasan_check_read+0x11/0x20 [ 25.281895] ? syscall_return_slowpath+0x510/0x510 [ 25.286797] ? SyS_rt_sigaction+0x94/0x1b0 [ 25.291019] ? lockdep_sys_exit+0x47/0xf0 [ 25.295139] ? retint_user+0x18/0x20 [ 25.298833] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 25.303654] entry_SYSENTER_compat+0x51/0x60 [ 25.308033] RIP: 0023:0xf7f3bc79 [ 25.311367] RSP: 002b:00000000ffdaffdc EFLAGS: 00000286 ORIG_RAX: 0000000000000036 [ 25.319049] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 25.326291] RDX: 00000000201dd000 RSI: 00000000080ef00c RDI: 000000000000003f [ 25.333533] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 25.340772] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 25.348012] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 25.355271] [ 25.356870] Allocated by task 2982: [ 25.360471] save_stack_trace+0x16/0x20 [ 25.364415] save_stack+0x43/0xd0 [ 25.367837] kasan_kmalloc+0xad/0xe0 [ 25.371521] __kmalloc_node+0x47/0x70 [ 25.375291] kvmalloc_node+0x64/0xd0 [ 25.378979] alloc_netdev_mqs+0x16e/0xed0 [ 25.383096] __tun_chr_ioctl+0x12be/0x3d20 [ 25.387299] tun_chr_compat_ioctl+0x29/0x30 [ 25.391592] compat_SyS_ioctl+0x1d7/0x3290 [ 25.395798] do_fast_syscall_32+0x3f2/0xf05 [ 25.400088] entry_SYSENTER_compat+0x51/0x60 [ 25.404465] [ 25.406064] Freed by task 2982: [ 25.409317] save_stack_trace+0x16/0x20 [ 25.413261] save_stack+0x43/0xd0 [ 25.416684] kasan_slab_free+0x71/0xc0 [ 25.420552] kfree+0xca/0x250 [ 25.423629] kvfree+0x36/0x60 [ 25.426708] free_netdev+0x2cf/0x360 [ 25.430390] __tun_chr_ioctl+0x2cf6/0x3d20 [ 25.434593] tun_chr_compat_ioctl+0x29/0x30 [ 25.438883] compat_SyS_ioctl+0x1d7/0x3290 [ 25.443086] do_fast_syscall_32+0x3f2/0xf05 [ 25.447378] entry_SYSENTER_compat+0x51/0x60 [ 25.451753] [ 25.453355] The buggy address belongs to the object at ffff8801ce760280 [ 25.453355] which belongs to the cache kmalloc-16384 of size 16384 [ 25.466328] The buggy address is located 13320 bytes inside of [ 25.466328] 16384-byte region [ffff8801ce760280, ffff8801ce764280) [ 25.478528] The buggy address belongs to the page: [ 25.483430] page:ffffea000739d800 count:1 mapcount:0 mapping:ffff8801ce760280 index:0x0 compound_mapcount: 0 [ 25.493376] flags: 0x200000000008100(slab|head) [ 25.498016] raw: 0200000000008100 ffff8801ce760280 0000000000000000 0000000100000001 [ 25.505866] raw: ffffea0007587620 ffffea00073ac620 ffff8801dac02200 0000000000000000 [ 25.513717] page dumped because: kasan: bad access detected [ 25.519398] [ 25.520995] Memory state around the buggy address: [ 25.525895] ffff8801ce763580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.533228] ffff8801ce763600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.540558] >ffff8801ce763680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.547886] ^ [ 25.551483] ffff8801ce763700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.558812] ffff8801ce763780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.566140] ================================================================== [ 25.573471] Disabling lock debugging due to kernel taint [ 25.578884] Kernel panic - not syncing: panic_on_warn set ... [ 25.578884] [ 25.586217] CPU: 0 PID: 2982 Comm: syzkaller183041 Tainted: G B 4.14.0-rc2+ #14 [ 25.594756] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.604075] Call Trace: [ 25.606635] dump_stack+0x194/0x257 [ 25.610229] ? arch_local_irq_restore+0x53/0x53 [ 25.614865] ? vprintk_default+0x28/0x30 [ 25.618895] ? __internal_add_timer+0x1f0/0x2d0 [ 25.623531] panic+0x1e4/0x417 [ 25.626687] ? __warn+0x1d9/0x1d9 [ 25.630112] ? __internal_add_timer+0x275/0x2d0 [ 25.634746] kasan_end_report+0x50/0x50 [ 25.638686] kasan_report+0x144/0x340 [ 25.642454] __asan_report_store8_noabort+0x17/0x20 [ 25.647435] __internal_add_timer+0x275/0x2d0 [ 25.651899] ? calc_wheel_index+0x200/0x200 [ 25.656195] mod_timer+0x622/0x15b0 [ 25.659797] ? mod_timer_pending+0x14e0/0x14e0 [ 25.664346] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 25.669327] ? trace_hardirqs_on+0xd/0x10 [ 25.673444] ? _crng_backtrack_protect+0xd9/0x130 [ 25.678257] ? __lock_is_held+0xbc/0x140 [ 25.682284] ? __lockdep_init_map+0xe4/0x650 [ 25.686658] ? lockdep_init_map+0x3d/0x70 [ 25.690773] ? rcu_read_lock_sched_held+0x108/0x120 [ 25.695754] ? init_timer_key+0x126/0x3b0 [ 25.699868] ? try_to_del_timer_sync+0x120/0x120 [ 25.704590] ? round_jiffies_up+0xce/0x100 [ 25.708790] ? __round_jiffies_up_relative+0x150/0x150 [ 25.714033] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 25.718931] __tun_chr_ioctl+0x1b23/0x3d20 [ 25.723135] ? tun_chr_read_iter+0x1e0/0x1e0 [ 25.727508] ? __pmd_alloc+0x4e0/0x4e0 [ 25.731366] ? __might_sleep+0x95/0x190 [ 25.735311] ? selinux_file_ioctl+0x444/0x690 [ 25.739771] ? __fget_light+0x29d/0x390 [ 25.743710] ? selinux_capable+0x40/0x40 [ 25.747747] tun_chr_compat_ioctl+0x29/0x30 [ 25.752031] ? tun_chr_compat_ioctl+0x29/0x30 [ 25.756496] compat_SyS_ioctl+0x1d7/0x3290 [ 25.760695] ? __handle_mm_fault+0x39c0/0x39c0 [ 25.765243] ? __tun_chr_ioctl+0x3d20/0x3d20 [ 25.769617] ? do_ioctl+0x60/0x60 [ 25.773041] ? do_fast_syscall_32+0x158/0xf05 [ 25.777505] ? do_ioctl+0x60/0x60 [ 25.780923] do_fast_syscall_32+0x3f2/0xf05 [ 25.785213] ? do_int80_syscall_32+0x940/0x940 [ 25.789761] ? kasan_check_read+0x11/0x20 [ 25.793876] ? syscall_return_slowpath+0x510/0x510 [ 25.798770] ? SyS_rt_sigaction+0x94/0x1b0 [ 25.802973] ? lockdep_sys_exit+0x47/0xf0 [ 25.807089] ? retint_user+0x18/0x20 [ 25.810768] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 25.815584] entry_SYSENTER_compat+0x51/0x60 [ 25.819956] RIP: 0023:0xf7f3bc79 [ 25.823284] RSP: 002b:00000000ffdaffdc EFLAGS: 00000286 ORIG_RAX: 0000000000000036 [ 25.830957] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000400454ca [ 25.838195] RDX: 00000000201dd000 RSI: 00000000080ef00c RDI: 000000000000003f [ 25.845429] RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 [ 25.852665] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 25.859900] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 25.867192] Dumping ftrace buffer: [ 25.870700] (ftrace buffer empty) [ 25.874379] Kernel Offset: disabled [ 25.877975] Rebooting in 86400 seconds..