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-0,10.128.15.193' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 61.877889] ================================================================== [ 61.879548] BUG: KASAN: use-after-free in free_ldt_struct.part.2+0x10a/0x150 [ 61.880635] Read of size 4 at addr ffff8801d8b44a08 by task syzkaller517388/10735 [ 61.881713] [ 61.881977] CPU: 0 PID: 10735 Comm: syzkaller517388 Not tainted 4.13.0-rc6+ #44 [ 61.883018] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.884270] Call Trace: [ 61.884673] dump_stack+0x194/0x257 [ 61.885184] ? arch_local_irq_restore+0x53/0x53 [ 61.885844] ? show_regs_print_info+0x65/0x65 [ 61.886471] ? free_ldt_struct.part.2+0x10a/0x150 [ 61.887171] print_address_description+0x73/0x250 [ 61.887857] ? free_ldt_struct.part.2+0x10a/0x150 [ 61.888544] kasan_report+0x24e/0x340 [ 61.889171] __asan_report_load4_noabort+0x14/0x20 [ 61.889950] free_ldt_struct.part.2+0x10a/0x150 [ 61.891252] ? rcu_pm_notify+0xc0/0xc0 [ 61.891798] destroy_context_ldt+0x60/0x80 [ 61.892385] __mmdrop+0xe9/0x530 [ 61.892843] ? sighand_ctor+0x50/0x50 [ 61.893357] ? trace_hardirqs_on+0xd/0x10 [ 61.893944] ? percpu_counter_add_batch+0xce/0x130 [ 61.894614] ? free_modinfo_version+0x70/0x70 [ 61.895245] ? __khugepaged_exit+0x43d/0x650 [ 61.895884] ? SyS_munmap+0x30/0x30 [ 61.896410] ? ___might_sleep+0x1/0x470 [ 61.896975] ? __might_sleep+0x95/0x190 [ 61.897567] mmput+0x541/0x6e0 [ 61.898033] ? get_task_exe_file+0xc0/0xc0 [ 61.902219] ? is_current_pgrp_orphaned+0xa0/0xa0 [ 61.907041] ? do_exit+0x979/0x1b10 [ 61.910647] ? lock_downgrade+0x990/0x990 [ 61.914779] ? do_raw_spin_trylock+0x190/0x190 [ 61.919349] ? down_read+0x96/0x150 [ 61.922962] ? do_exit+0x49c/0x1b10 [ 61.926581] ? __down_interruptible+0x6a0/0x6a0 [ 61.931230] ? trace_hardirqs_on+0xd/0x10 [ 61.935350] ? _raw_spin_unlock_irq+0x27/0x70 [ 61.939818] do_exit+0x989/0x1b10 [ 61.943243] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 61.948424] ? mm_update_next_owner+0x930/0x930 [ 61.953071] ? __cleanup_sighand+0x40/0x40 [ 61.957290] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 61.962277] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 61.967263] ? trace_hardirqs_on+0xd/0x10 [ 61.971382] ? print_usage_bug+0x480/0x480 [ 61.975593] ? check_noncircular+0x20/0x20 [ 61.979801] ? drain_local_pages_wq+0x20/0x20 [ 61.984303] ? find_held_lock+0x35/0x1d0 [ 61.988339] ? get_signal+0x855/0x17e0 [ 61.992203] ? lock_downgrade+0x990/0x990 [ 61.996974] do_group_exit+0x149/0x400 [ 62.000835] ? __lock_is_held+0xb6/0x140 [ 62.004866] ? SyS_exit+0x30/0x30 [ 62.008292] ? _raw_spin_unlock_irq+0x27/0x70 [ 62.012759] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 62.017757] get_signal+0x7e8/0x17e0 [ 62.021488] ? ptrace_notify+0x130/0x130 [ 62.025543] ? check_noncircular+0x20/0x20 [ 62.029751] do_signal+0x94/0x1ee0 [ 62.033265] ? _do_fork+0x1ef/0xfb0 [ 62.036860] ? _do_fork+0x2dc/0xfb0 [ 62.040457] ? setup_sigcontext+0x7d0/0x7d0 [ 62.044766] ? fork_idle+0x2d0/0x2d0 [ 62.048446] ? find_held_lock+0x35/0x1d0 [ 62.052484] ? kprobe_flush_task+0x1a3/0x5d0 [ 62.056868] ? do_raw_spin_trylock+0x190/0x190 [ 62.061423] ? find_held_lock+0x35/0x1d0 [ 62.065456] ? exit_to_usermode_loop+0x98/0x300 [ 62.070099] exit_to_usermode_loop+0x224/0x300 [ 62.074651] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 62.080164] do_syscall_64+0x5d4/0x800 [ 62.084031] ? syscall_return_slowpath+0x450/0x450 [ 62.088929] ? syscall_return_slowpath+0x22f/0x450 [ 62.093827] ? prepare_exit_to_usermode+0x220/0x220 [ 62.098812] ? entry_SYSCALL_64_fastpath+0x5/0xbe [ 62.103631] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 62.108452] ? sys_vfork+0x30/0x30 [ 62.111963] entry_SYSCALL64_slow_path+0x25/0x25 [ 62.116685] RIP: 0033:0x449fa9 [ 62.119845] RSP: 002b:00007fa315396dc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 [ 62.127521] RAX: fffffffffffffdff RBX: 0000000000000000 RCX: 0000000000449fa9 [ 62.134758] RDX: 0000000020507ffc RSI: 00000000208a8f43 RDI: 0000000000800000 [ 62.141995] RBP: 0000000000000000 R08: 0000000020a8a000 R09: 00007fa315397700 [ 62.149236] R10: 0000000020117ffc R11: 0000000000000202 R12: 0000000000000000 [ 62.156474] R13: 00007fff1e31279f R14: 00007fa3153979c0 R15: 0000000000000000 [ 62.163727] [ 62.165327] Allocated by task 10690: [ 62.169016] save_stack_trace+0x16/0x20 [ 62.172961] save_stack+0x43/0xd0 [ 62.176379] kasan_kmalloc+0xad/0xe0 [ 62.180060] kmem_cache_alloc_trace+0x12f/0x740 [ 62.184695] alloc_ldt_struct+0x52/0x140 [ 62.188722] write_ldt+0x7b4/0xac0 [ 62.192229] sys_modify_ldt+0x1ef/0x240 [ 62.196171] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 62.200890] [ 62.202485] Freed by task 10735: [ 62.205819] save_stack_trace+0x16/0x20 [ 62.209762] save_stack+0x43/0xd0 [ 62.213181] kasan_slab_free+0x71/0xc0 [ 62.217036] kfree+0xca/0x250 [ 62.220111] free_ldt_struct.part.2+0xdd/0x150 [ 62.224657] destroy_context_ldt+0x60/0x80 [ 62.228858] __mmdrop+0xe9/0x530 [ 62.232190] mmput+0x541/0x6e0 [ 62.235350] copy_process.part.34+0x2315/0x4bd0 [ 62.239988] _do_fork+0x1ef/0xfb0 [ 62.243416] SyS_clone+0x37/0x50 [ 62.246747] do_syscall_64+0x26c/0x800 [ 62.250601] return_from_SYSCALL_64+0x0/0x7a [ 62.254972] [ 62.256569] The buggy address belongs to the object at ffff8801d8b44a00 [ 62.256569] which belongs to the cache kmalloc-32 of size 32 [ 62.269024] The buggy address is located 8 bytes inside of [ 62.269024] 32-byte region [ffff8801d8b44a00, ffff8801d8b44a20) [ 62.280602] The buggy address belongs to the page: [ 62.285500] page:ffffea000762d100 count:1 mapcount:0 mapping:ffff8801d8b44000 index:0xffff8801d8b44fc1 [ 62.294912] flags: 0x200000000000100(slab) [ 62.299116] raw: 0200000000000100 ffff8801d8b44000 ffff8801d8b44fc1 000000010000003f [ 62.306962] raw: ffffea000762efa0 ffffea000762a360 ffff8801dac001c0 0000000000000000 [ 62.314809] page dumped because: kasan: bad access detected [ 62.320483] [ 62.322077] Memory state around the buggy address: [ 62.326972] ffff8801d8b44900: 00 00 00 00 fc fc fc fc fb fb fb fb fc fc fc fc [ 62.334297] ffff8801d8b44980: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc [ 62.341627] >ffff8801d8b44a00: fb fb fb fb fc fc fc fc 06 fc fc fc fc fc fc fc [ 62.348958] ^ [ 62.352550] ffff8801d8b44a80: 00 fc fc fc fc fc fc fc 04 fc fc fc fc fc fc fc [ 62.359877] ffff8801d8b44b00: 00 fc fc fc fc fc fc fc 00 02 fc fc fc fc fc fc [ 62.367205] ================================================================== [ 62.374528] Disabling lock debugging due to kernel taint executing program executing program [ 62.380285] Kernel panic - not syncing: panic_on_warn set ... [ 62.380285] [ 62.387636] CPU: 0 PID: 10735 Comm: syzkaller517388 Tainted: G B 4.13.0-rc6+ #44 [ 62.396284] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.405627] Call Trace: [ 62.408215] dump_stack+0x194/0x257 [ 62.411831] ? arch_local_irq_restore+0x53/0x53 [ 62.416486] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 62.421229] ? free_ldt_struct.part.2+0x30/0x150 [ 62.425974] panic+0x1e4/0x417 executing program executing program executing program executing program executing program [ 62.429150] ? __warn+0x1d9/0x1d9 [ 62.432596] ? free_ldt_struct.part.2+0x10a/0x150 [ 62.437425] kasan_end_report+0x50/0x50 [ 62.441385] kasan_report+0x137/0x340 [ 62.445171] __asan_report_load4_noabort+0x14/0x20 [ 62.450090] free_ldt_struct.part.2+0x10a/0x150 [ 62.454746] ? rcu_pm_notify+0xc0/0xc0 [ 62.458622] destroy_context_ldt+0x60/0x80 [ 62.462841] __mmdrop+0xe9/0x530 [ 62.466191] ? sighand_ctor+0x50/0x50 [ 62.469983] ? trace_hardirqs_on+0xd/0x10 [ 62.474125] ? percpu_counter_add_batch+0xce/0x130 executing program executing program [ 62.479047] ? free_modinfo_version+0x70/0x70 [ 62.483526] ? __khugepaged_exit+0x43d/0x650 [ 62.487932] ? SyS_munmap+0x30/0x30 [ 62.491561] ? ___might_sleep+0x1/0x470 [ 62.495527] ? __might_sleep+0x95/0x190 [ 62.499494] mmput+0x541/0x6e0 [ 62.502688] ? get_task_exe_file+0xc0/0xc0 [ 62.506924] ? is_current_pgrp_orphaned+0xa0/0xa0 [ 62.511761] ? do_exit+0x979/0x1b10 [ 62.515388] ? lock_downgrade+0x990/0x990 [ 62.519534] ? do_raw_spin_trylock+0x190/0x190 [ 62.524114] ? down_read+0x96/0x150 [ 62.527742] ? do_exit+0x49c/0x1b10 [ 62.531353] ? __down_interruptible+0x6a0/0x6a0 [ 62.536007] ? trace_hardirqs_on+0xd/0x10 [ 62.540138] ? _raw_spin_unlock_irq+0x27/0x70 [ 62.544623] do_exit+0x989/0x1b10 [ 62.548063] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 62.553267] ? mm_update_next_owner+0x930/0x930 [ 62.557944] ? __cleanup_sighand+0x40/0x40 [ 62.562171] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 62.567178] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 62.572180] ? trace_hardirqs_on+0xd/0x10 [ 62.576311] ? print_usage_bug+0x480/0x480 [ 62.580536] ? check_noncircular+0x20/0x20 [ 62.584765] ? drain_local_pages_wq+0x20/0x20 [ 62.589272] ? find_held_lock+0x35/0x1d0 [ 62.593324] ? get_signal+0x855/0x17e0 [ 62.597199] ? lock_downgrade+0x990/0x990 [ 62.601340] do_group_exit+0x149/0x400 [ 62.605215] ? __lock_is_held+0xb6/0x140 [ 62.609285] ? SyS_exit+0x30/0x30 [ 62.612721] ? _raw_spin_unlock_irq+0x27/0x70 [ 62.617201] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 62.622212] get_signal+0x7e8/0x17e0 [ 62.625931] ? ptrace_notify+0x130/0x130 [ 62.629997] ? check_noncircular+0x20/0x20 [ 62.634225] do_signal+0x94/0x1ee0 [ 62.637759] ? _do_fork+0x1ef/0xfb0 [ 62.641369] ? _do_fork+0x2dc/0xfb0 [ 62.644978] ? setup_sigcontext+0x7d0/0x7d0 [ 62.649286] ? fork_idle+0x2d0/0x2d0 [ 62.652982] ? find_held_lock+0x35/0x1d0 [ 62.657046] ? kprobe_flush_task+0x1a3/0x5d0 [ 62.661459] ? do_raw_spin_trylock+0x190/0x190 [ 62.666029] ? find_held_lock+0x35/0x1d0 [ 62.670098] ? exit_to_usermode_loop+0x98/0x300 [ 62.674771] exit_to_usermode_loop+0x224/0x300 [ 62.679343] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 62.684875] do_syscall_64+0x5d4/0x800 [ 62.688754] ? syscall_return_slowpath+0x450/0x450 [ 62.693671] ? syscall_return_slowpath+0x22f/0x450 [ 62.698589] ? prepare_exit_to_usermode+0x220/0x220 [ 62.703592] ? entry_SYSCALL_64_fastpath+0x5/0xbe [ 62.708419] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 62.713253] ? sys_vfork+0x30/0x30 [ 62.716793] entry_SYSCALL64_slow_path+0x25/0x25 [ 62.721558] RIP: 0033:0x449fa9 [ 62.724751] RSP: 002b:00007fa315396dc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 [ 62.732456] RAX: fffffffffffffdff RBX: 0000000000000000 RCX: 0000000000449fa9 [ 62.739708] RDX: 0000000020507ffc RSI: 00000000208a8f43 RDI: 0000000000800000 [ 62.746964] RBP: 0000000000000000 R08: 0000000020a8a000 R09: 00007fa315397700 [ 62.754230] R10: 0000000020117ffc R11: 0000000000000202 R12: 0000000000000000 [ 62.761504] R13: 00007fff1e31279f R14: 00007fa3153979c0 R15: 0000000000000000 [ 62.769205] Dumping ftrace buffer: [ 62.772716] (ftrace buffer empty) [ 62.776391] Kernel Offset: disabled [ 62.779981] Rebooting in 86400 seconds..