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-7,10.128.0.56' (ECDSA) to the list of known hosts. net.ipv6.conf.syz2.accept_dad = 0 net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz5.accept_dad = 0 net.ipv6.conf.syz7.accept_dad = 0 net.ipv6.conf.syz3.accept_dad = 0 net.ipv6.conf.syz6.accept_dad = 0 net.ipv6.conf.syz4.accept_dad = 0 net.ipv6.conf.syz1.accept_dad = 0 net.ipv6.conf.syz2.router_solicitations = 0 net.ipv6.conf.syz0.router_solicitations = 0 net.ipv6.conf.syz7.router_solicitations = 0 net.ipv6.conf.syz3.router_solicitations = 0 net.ipv6.conf.syz4.router_solicitations = 0 net.ipv6.conf.syz6.router_solicitations = 0 net.ipv6.conf.syz1.router_solicitations = 0 net.ipv6.conf.syz5.router_solicitations = 0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program 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: [ 59.125833] ================================================================== [ 59.127036] BUG: KASAN: use-after-free in free_ldt_struct.part.2+0x10a/0x150 [ 59.128020] Read of size 4 at addr ffff8801dadd3848 by task syzkaller975859/17168 [ 59.129047] [ 59.129314] CPU: 0 PID: 17168 Comm: syzkaller975859 Not tainted 4.13.0-rc6+ #44 [ 59.130325] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 59.131636] Call Trace: [ 59.131995] dump_stack+0x194/0x257 [ 59.132566] ? arch_local_irq_restore+0x53/0x53 [ 59.133222] ? show_regs_print_info+0x65/0x65 [ 59.134011] ? free_ldt_struct.part.2+0x10a/0x150 [ 59.135007] print_address_description+0x73/0x250 [ 59.135805] ? free_ldt_struct.part.2+0x10a/0x150 [ 59.136565] kasan_report+0x24e/0x340 [ 59.137122] __asan_report_load4_noabort+0x14/0x20 [ 59.137848] free_ldt_struct.part.2+0x10a/0x150 [ 59.138629] ? rcu_pm_notify+0xc0/0xc0 [ 59.139417] destroy_context_ldt+0x60/0x80 [ 59.140147] __mmdrop+0xe9/0x530 [ 59.140901] ? sighand_ctor+0x50/0x50 [ 59.141638] ? trace_hardirqs_on+0xd/0x10 [ 59.142219] ? percpu_counter_add_batch+0xce/0x130 [ 59.142934] ? free_modinfo_version+0x70/0x70 [ 59.143608] ? __khugepaged_exit+0x43d/0x650 [ 59.144229] ? SyS_munmap+0x30/0x30 [ 59.144835] ? ___might_sleep+0x1/0x470 [ 59.145696] ? __might_sleep+0x95/0x190 [ 59.148100] mmput+0x541/0x6e0 [ 59.151310] ? get_task_exe_file+0xc0/0xc0 [ 59.155535] ? is_current_pgrp_orphaned+0xa0/0xa0 [ 59.160367] ? do_exit+0x979/0x1b10 [ 59.163981] ? lock_downgrade+0x990/0x990 [ 59.168124] ? do_raw_spin_trylock+0x190/0x190 executing program [ 59.172699] ? down_read+0x96/0x150 [ 59.176306] ? do_exit+0x49c/0x1b10 [ 59.179906] ? __down_interruptible+0x6a0/0x6a0 [ 59.184546] ? trace_hardirqs_on+0xd/0x10 [ 59.188665] ? _raw_spin_unlock_irq+0x27/0x70 [ 59.193135] do_exit+0x989/0x1b10 [ 59.196561] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 59.201732] ? mm_update_next_owner+0x930/0x930 [ 59.206397] ? __cleanup_sighand+0x40/0x40 [ 59.210645] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 59.215643] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 59.220646] ? trace_hardirqs_on+0xd/0x10 [ 59.224778] ? print_usage_bug+0x480/0x480 [ 59.229175] ? check_noncircular+0x20/0x20 [ 59.233388] ? drain_local_pages_wq+0x20/0x20 [ 59.237890] ? find_held_lock+0x35/0x1d0 [ 59.241954] ? get_signal+0x855/0x17e0 [ 59.245813] ? lock_downgrade+0x990/0x990 [ 59.249938] do_group_exit+0x149/0x400 [ 59.253812] ? __lock_is_held+0xb6/0x140 [ 59.257842] ? SyS_exit+0x30/0x30 [ 59.261262] ? _raw_spin_unlock_irq+0x27/0x70 [ 59.265728] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 59.270729] get_signal+0x7e8/0x17e0 [ 59.274451] ? ptrace_notify+0x130/0x130 [ 59.278507] ? check_noncircular+0x20/0x20 [ 59.282730] do_signal+0x94/0x1ee0 [ 59.286250] ? _do_fork+0x1ef/0xfb0 [ 59.289847] ? _do_fork+0x2dc/0xfb0 [ 59.293445] ? setup_sigcontext+0x7d0/0x7d0 [ 59.297737] ? fork_idle+0x2d0/0x2d0 [ 59.301419] ? find_held_lock+0x35/0x1d0 [ 59.305459] ? kprobe_flush_task+0x1a3/0x5d0 [ 59.309851] ? do_raw_spin_trylock+0x190/0x190 [ 59.314421] ? find_held_lock+0x35/0x1d0 [ 59.318453] ? exit_to_usermode_loop+0x98/0x300 executing program [ 59.323096] exit_to_usermode_loop+0x224/0x300 [ 59.327653] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 59.333171] do_syscall_64+0x5d4/0x800 [ 59.337057] ? syscall_return_slowpath+0x450/0x450 [ 59.341973] ? syscall_return_slowpath+0x22f/0x450 [ 59.346891] ? prepare_exit_to_usermode+0x220/0x220 [ 59.351898] ? entry_SYSCALL_64_fastpath+0x5/0xbe [ 59.356723] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 59.361541] ? sys_vfork+0x30/0x30 [ 59.365059] entry_SYSCALL64_slow_path+0x25/0x25 [ 59.369808] RIP: 0033:0x44b549 executing program [ 59.372982] RSP: 002b:00007f184677bd08 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 [ 59.380672] RAX: fffffffffffffdff RBX: 0000000000000000 RCX: 000000000044b549 [ 59.387915] RDX: 0000000020001000 RSI: 0000000020001000 RDI: 0000000000000000 [ 59.395164] RBP: 0000000000000000 R08: 0000000020000000 R09: 00007f184677c700 [ 59.402407] R10: 0000000020001000 R11: 0000000000000246 R12: 0000000000000000 [ 59.409649] R13: 00007ffcff58edaf R14: 00007f184677c9c0 R15: 0000000000000000 [ 59.416903] [ 59.418500] Allocated by task 17156: [ 59.422188] save_stack_trace+0x16/0x20 executing program [ 59.426140] save_stack+0x43/0xd0 [ 59.429563] kasan_kmalloc+0xad/0xe0 [ 59.433249] kmem_cache_alloc_trace+0x12f/0x740 [ 59.437901] alloc_ldt_struct+0x52/0x140 [ 59.441930] write_ldt+0x3e9/0xac0 [ 59.445439] sys_modify_ldt+0x1ef/0x240 [ 59.449406] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 59.454160] [ 59.455770] Freed by task 17168: [ 59.459114] save_stack_trace+0x16/0x20 [ 59.463069] save_stack+0x43/0xd0 [ 59.466508] kasan_slab_free+0x71/0xc0 [ 59.470365] kfree+0xca/0x250 executing program [ 59.473439] free_ldt_struct.part.2+0xdd/0x150 [ 59.477988] destroy_context_ldt+0x60/0x80 [ 59.482202] __mmdrop+0xe9/0x530 [ 59.485545] mmput+0x541/0x6e0 [ 59.488705] copy_process.part.34+0x2315/0x4bd0 [ 59.493341] _do_fork+0x1ef/0xfb0 [ 59.496763] SyS_clone+0x37/0x50 [ 59.500098] do_syscall_64+0x26c/0x800 [ 59.503972] return_from_SYSCALL_64+0x0/0x7a [ 59.508353] [ 59.509951] The buggy address belongs to the object at ffff8801dadd3840 [ 59.509951] which belongs to the cache kmalloc-32 of size 32 [ 59.522398] The buggy address is located 8 bytes inside of [ 59.522398] 32-byte region [ffff8801dadd3840, ffff8801dadd3860) [ 59.534009] The buggy address belongs to the page: [ 59.538915] page:ffffea00076b74c0 count:1 mapcount:0 mapping:ffff8801dadd3000 index:0xffff8801dadd3fc1 [ 59.548335] flags: 0x200000000000100(slab) [ 59.552547] raw: 0200000000000100 ffff8801dadd3000 ffff8801dadd3fc1 000000010000003f [ 59.560396] raw: ffffea00076b7520 ffffea00076b7420 ffff8801dac001c0 0000000000000000 [ 59.568240] page dumped because: kasan: bad access detected [ 59.573913] [ 59.575509] Memory state around the buggy address: [ 59.580412] ffff8801dadd3700: fb fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc [ 59.587737] ffff8801dadd3780: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc [ 59.595063] >ffff8801dadd3800: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc [ 59.602389] ^ [ 59.608065] ffff8801dadd3880: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc [ 59.615405] ffff8801dadd3900: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc [ 59.622743] ================================================================== [ 59.630083] Disabling lock debugging due to kernel taint [ 59.635650] Kernel panic - not syncing: panic_on_warn set ... [ 59.635650] [ 59.643000] CPU: 0 PID: 17168 Comm: syzkaller975859 Tainted: G B 4.13.0-rc6+ #44 [ 59.651649] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 59.660974] Call Trace: [ 59.663535] dump_stack+0x194/0x257 [ 59.667140] ? arch_local_irq_restore+0x53/0x53 [ 59.671787] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 59.676522] ? fr