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-mmots-kasan-gce-5,10.128.0.28' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 52.257742] ================================================================== [ 52.258917] BUG: KASAN: use-after-free in __internal_add_timer+0x275/0x2d0 [ 52.259844] Write of size 8 at addr ffff8801ce033688 by task syzkaller909118/2979 [ 52.260872] [ 52.261111] CPU: 0 PID: 2979 Comm: syzkaller909118 Not tainted 4.14.0-rc4-mm1+ #16 [ 52.262136] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.263361] Call Trace: [ 52.263722] dump_stack+0x194/0x257 [ 52.264229] ? arch_local_irq_restore+0x53/0x53 [ 52.264912] ? show_regs_print_info+0x65/0x65 [ 52.265522] ? __internal_add_timer+0x275/0x2d0 [ 52.266173] print_address_description+0x73/0x250 [ 52.266821] ? __internal_add_timer+0x275/0x2d0 [ 52.267450] kasan_report+0x25b/0x340 [ 52.267969] __asan_report_store8_noabort+0x17/0x20 [ 52.268652] __internal_add_timer+0x275/0x2d0 [ 52.269307] ? calc_wheel_index+0x200/0x200 [ 52.269920] mod_timer+0x622/0x15b0 [ 52.270446] ? mod_timer_pending+0x14e0/0x14e0 [ 52.271107] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 52.271779] ? trace_hardirqs_on+0xd/0x10 [ 52.272345] ? _crng_backtrack_protect+0xd9/0x130 [ 52.273019] ? __lock_is_held+0xbc/0x140 [ 52.273572] ? __lockdep_init_map+0xe4/0x650 [ 52.274180] ? lockdep_init_map+0x3d/0x70 [ 52.274742] ? rcu_read_lock_sched_held+0x108/0x120 [ 52.275432] ? init_timer_key+0x126/0x3b0 [ 52.275995] ? try_to_del_timer_sync+0x120/0x120 [ 52.276636] ? round_jiffies_up+0xce/0x100 [ 52.277219] ? __round_jiffies_up_relative+0x150/0x150 [ 52.277926] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 52.282841] __tun_chr_ioctl+0x1beb/0x3e40 [ 52.287058] ? tun_chr_read_iter+0x1e0/0x1e0 [ 52.291434] ? lock_downgrade+0x990/0x990 [ 52.295577] ? handle_mm_fault+0x410/0x8d0 [ 52.299785] ? __do_page_fault+0x31e/0xd60 [ 52.304009] ? check_same_owner+0x320/0x320 [ 52.308301] ? up_read+0x1a/0x40 [ 52.311640] ? __do_page_fault+0x3d6/0xd60 [ 52.315852] ? tun_chr_compat_ioctl+0x30/0x30 [ 52.320317] tun_chr_ioctl+0x2a/0x40 [ 52.324001] ? tun_chr_ioctl+0x2a/0x40 [ 52.327864] do_vfs_ioctl+0x1b1/0x1530 [ 52.331734] ? ioctl_preallocate+0x2b0/0x2b0 [ 52.336118] ? selinux_capable+0x40/0x40 [ 52.340152] ? putname+0xf3/0x130 [ 52.343579] ? do_sys_open+0x320/0x6d0 [ 52.347451] ? security_file_ioctl+0x89/0xb0 [ 52.351837] SyS_ioctl+0x8f/0xc0 [ 52.355180] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 52.359903] RIP: 0033:0x443d69 [ 52.363068] RSP: 002b:00007ffc82ed58a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 [ 52.370751] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443d69 [ 52.377993] RDX: 00000000207cdff1 RSI: 00000000400454ca RDI: 0000000000000004 [ 52.385233] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 52.392473] R10: 0000000000000000 R11: 0000000000000206 R12: 9df3cabc73b95167 [ 52.399713] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 52.406973] [ 52.408572] Allocated by task 2979: [ 52.412170] save_stack+0x43/0xd0 [ 52.415591] kasan_kmalloc+0xad/0xe0 [ 52.419276] __kmalloc_node+0x47/0x70 [ 52.423054] kvmalloc_node+0x64/0xd0 [ 52.426741] alloc_netdev_mqs+0x16d/0xed0 [ 52.430859] __tun_chr_ioctl+0x1386/0x3e40 [ 52.435066] tun_chr_ioctl+0x2a/0x40 [ 52.438752] do_vfs_ioctl+0x1b1/0x1530 [ 52.442609] SyS_ioctl+0x8f/0xc0 [ 52.445945] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 52.450668] [ 52.452266] Freed by task 2979: [ 52.455514] save_stack+0x43/0xd0 [ 52.458941] kasan_slab_free+0x71/0xc0 [ 52.462806] kfree+0xca/0x250 [ 52.465883] kvfree+0x36/0x60 [ 52.468959] free_netdev+0x2cf/0x360 [ 52.472643] __tun_chr_ioctl+0x2df6/0x3e40 [ 52.476849] tun_chr_ioctl+0x2a/0x40 [ 52.480534] do_vfs_ioctl+0x1b1/0x1530 [ 52.484394] SyS_ioctl+0x8f/0xc0 [ 52.487729] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 52.492450] [ 52.494048] The buggy address belongs to the object at ffff8801ce030280 [ 52.494048] which belongs to the cache kmalloc-16384 of size 16384 [ 52.507020] The buggy address is located 13320 bytes inside of [ 52.507020] 16384-byte region [ffff8801ce030280, ffff8801ce034280) [ 52.519208] The buggy address belongs to the page: [ 52.524109] page:ffffea0007380c00 count:1 mapcount:0 mapping:ffff8801ce030280 index:0x0 compound_mapcount: 0 [ 52.534056] flags: 0x200000000008100(slab|head) [ 52.538699] raw: 0200000000008100 ffff8801ce030280 0000000000000000 0000000100000001 [ 52.546552] raw: ffffea000756b820 ffffea0007380420 ffff8801dac02200 0000000000000000 [ 52.554400] page dumped because: kasan: bad access detected [ 52.560077] [ 52.561673] Memory state around the buggy address: [ 52.566573] ffff8801ce033580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.573902] ffff8801ce033600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.581231] >ffff8801ce033680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.588572] ^ [ 52.592169] ffff8801ce033700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.599499] ffff8801ce033780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 52.606828] ================================================================== [ 52.614153] Disabling lock debugging due to kernel taint [ 52.619568] Kernel panic - not syncing: panic_on_warn set ... [ 52.619568] [ 52.627067] CPU: 0 PID: 2979 Comm: syzkaller909118 Tainted: G B 4.14.0-rc4-mm1+ #16 [ 52.636037] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 52.645353] Call Trace: [ 52.647908] dump_stack+0x194/0x257 [ 52.651503] ? arch_local_irq_restore+0x53/0x53 [ 52.656139] ? vprintk_default+0x28/0x30 [ 52.660167] ? __internal_add_timer+0x1f0/0x2d0 [ 52.664801] panic+0x1e4/0x41c [ 52.667959] ? refcount_error_report+0x214/0x214 [ 52.672686] ? __internal_add_timer+0x275/0x2d0 [ 52.677319] kasan_end_report+0x50/0x50 [ 52.681258] kasan_report+0x144/0x340 [ 52.685025] __asan_report_store8_noabort+0x17/0x20 [ 52.690003] __internal_add_timer+0x275/0x2d0 [ 52.694463] ? calc_wheel_index+0x200/0x200 [ 52.698754] mod_timer+0x622/0x15b0 [ 52.702352] ? mod_timer_pending+0x14e0/0x14e0 [ 52.706899] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 52.711883] ? trace_hardirqs_on+0xd/0x10 [ 52.716002] ? _crng_backtrack_protect+0xd9/0x130 [ 52.720813] ? __lock_is_held+0xbc/0x140 [ 52.724840] ? __lockdep_init_map+0xe4/0x650 [ 52.729214] ? lockdep_init_map+0x3d/0x70 [ 52.733327] ? rcu_read_lock_sched_held+0x108/0x120 [ 52.738310] ? init_timer_key+0x126/0x3b0 [ 52.742433] ? try_to_del_timer_sync+0x120/0x120 [ 52.747157] ? round_jiffies_up+0xce/0x100 [ 52.751356] ? __round_jiffies_up_relative+0x150/0x150 [ 52.756596] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 52.761496] __tun_chr_ioctl+0x1beb/0x3e40 [ 52.765703] ? tun_chr_read_iter+0x1e0/0x1e0 [ 52.770077] ? lock_downgrade+0x990/0x990 [ 52.774201] ? handle_mm_fault+0x410/0x8d0 [ 52.778401] ? __do_page_fault+0x31e/0xd60 [ 52.782607] ? check_same_owner+0x320/0x320 [ 52.786892] ? up_read+0x1a/0x40 [ 52.790222] ? __do_page_fault+0x3d6/0xd60 [ 52.794422] ? tun_chr_compat_ioctl+0x30/0x30 [ 52.798880] tun_chr_ioctl+0x2a/0x40 [ 52.802557] ? tun_chr_ioctl+0x2a/0x40 [ 52.806409] do_vfs_ioctl+0x1b1/0x1530 [ 52.810264] ? ioctl_preallocate+0x2b0/0x2b0 [ 52.814639] ? selinux_capable+0x40/0x40 [ 52.818666] ? putname+0xf3/0x130 [ 52.822085] ? do_sys_open+0x320/0x6d0 [ 52.825963] ? security_file_ioctl+0x89/0xb0 [ 52.830337] SyS_ioctl+0x8f/0xc0 [ 52.833671] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 52.838402] RIP: 0033:0x443d69 [ 52.841560] RSP: 002b:00007ffc82ed58a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 [ 52.849232] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000443d69 [ 52.856466] RDX: 00000000207cdff1 RSI: 00000000400454ca RDI: 0000000000000004 [ 52.863700] RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 [ 52.870936] R10: 0000000000000000 R11: 0000000000000206 R12: 9df3cabc73b95167 [ 52.878171] R13: 74656e2f7665642f R14: 0000000000000000 R15: 0000000000000000 [ 52.885452] Dumping ftrace buffer: [ 52.888961] (ftrace buffer empty) [ 52.892635] Kernel Offset: disabled [ 52.896227] Rebooting in 86400 seconds..