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-mmots-kasan-gce-3,10.128.0.29' (ECDSA) to the list of known hosts. 2017/09/20 16:31:47 parsed 1 programs 2017/09/20 16:31:47 executed programs: 0 2017/09/20 16:31:52 executed programs: 167 syzkaller login: [ 396.838995] ================================================================== [ 396.846486] BUG: KASAN: use-after-free in userfaultfd_release+0x5c1/0x6e0 [ 396.853384] Read of size 8 at addr ffff8801c90cb388 by task syz-executor0/4268 [ 396.860710] [ 396.862313] CPU: 0 PID: 4268 Comm: syz-executor0 Not tainted 4.13.0-mm1+ #7 [ 396.869380] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 396.878703] Call Trace: [ 396.881267] dump_stack+0x194/0x257 [ 396.884870] ? arch_local_irq_restore+0x53/0x53 [ 396.889511] ? show_regs_print_info+0x65/0x65 [ 396.893993] ? unwind_get_return_address+0x61/0xa0 [ 396.898895] ? userfaultfd_release+0x5c1/0x6e0 [ 396.903452] print_address_description+0x73/0x250 [ 396.908265] ? userfaultfd_release+0x5c1/0x6e0 [ 396.912818] kasan_report+0x24e/0x340 [ 396.916592] ? userfaultfd_event_wait_completion+0x910/0x910 [ 396.922362] __asan_report_load8_noabort+0x14/0x20 [ 396.927259] userfaultfd_release+0x5c1/0x6e0 [ 396.931642] ? fcntl_setlk+0x10d0/0x10d0 [ 396.935679] ? userfaultfd_event_wait_completion+0x910/0x910 [ 396.941450] ? fsnotify+0x1af0/0x1af0 [ 396.945230] ? __might_sleep+0x95/0x190 [ 396.949178] ? userfaultfd_event_wait_completion+0x910/0x910 [ 396.954947] __fput+0x333/0x7f0 [ 396.958203] ? fput+0x140/0x140 [ 396.961456] ? _raw_spin_unlock_irq+0x27/0x70 [ 396.965927] ____fput+0x15/0x20 [ 396.969178] task_work_run+0x199/0x270 [ 396.973038] ? task_work_cancel+0x210/0x210 [ 396.977331] ? _raw_spin_unlock+0x22/0x30 [ 396.981450] ? switch_task_namespaces+0x87/0xc0 [ 396.986097] do_exit+0xa52/0x1b40 [ 396.989528] ? do_raw_spin_trylock+0x190/0x190 [ 396.994082] ? do_raw_spin_trylock+0x190/0x190 [ 396.998645] ? mm_update_next_owner+0x930/0x930 [ 397.003291] ? trace_hardirqs_off+0xd/0x10 [ 397.007498] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 397.012750] ? try_to_wake_up+0x115/0x1850 [ 397.016959] ? check_noncircular+0x20/0x20 [ 397.021167] ? migrate_swap_stop+0x970/0x970 [ 397.025553] ? lock_downgrade+0x990/0x990 [ 397.029684] ? find_held_lock+0x39/0x1d0 [ 397.033726] ? lock_downgrade+0x990/0x990 [ 397.037842] ? __handle_mm_fault+0x39c0/0x39c0 [ 397.042395] ? vmacache_find+0x61/0x270 [ 397.046340] ? retint_kernel+0x10/0x10 [ 397.050200] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 397.055192] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 397.059924] ? retint_kernel+0x10/0x10 [ 397.063794] ? _raw_spin_unlock_irq+0x56/0x70 [ 397.068264] do_group_exit+0x149/0x400 [ 397.072120] ? lockdep_sys_exit+0x47/0xf0 [ 397.076237] ? SyS_exit+0x30/0x30 [ 397.079667] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 397.084655] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 397.089383] SyS_exit_group+0x1d/0x20 [ 397.093156] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 397.097881] RIP: 0033:0x4520a9 [ 397.101041] RSP: 002b:00007ffd274e6a38 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 [ 397.108722] RAX: ffffffffffffffda RBX: 0000000001096914 RCX: 00000000004520a9 [ 397.115971] RDX: 00000000004520a9 RSI: 0000000000760618 RDI: 0000000000000000 [ 397.123211] RBP: 0000000000000082 R08: 00000000007180b0 R09: 00000000000010a7 [ 397.130450] R10: 0000000000760610 R11: 0000000000000202 R12: 0000000000000045 [ 397.137690] R13: 00000000007180b0 R14: 00000000007180dc R15: 0000000000000016 [ 397.144948] [ 397.146548] Allocated by task 4270: [ 397.150150] save_stack_trace+0x16/0x20 [ 397.154096] save_stack+0x43/0xd0 [ 397.157516] kasan_kmalloc+0xad/0xe0 [ 397.161200] kasan_slab_alloc+0x12/0x20 [ 397.165143] kmem_cache_alloc+0x12e/0x760 [ 397.169260] dup_userfaultfd+0x21c/0x890 [ 397.173293] copy_mm+0xa38/0x1310 [ 397.176714] copy_process.part.36+0x1eae/0x4af0 [ 397.181670] _do_fork+0x1ef/0xfe0 [ 397.185092] SyS_clone+0x37/0x50 [ 397.188429] do_syscall_64+0x26c/0x8c0 [ 397.192287] return_from_SYSCALL_64+0x0/0x7a [ 397.196660] [ 397.198256] Freed by task 4270: [ 397.201506] save_stack_trace+0x16/0x20 [ 397.205446] save_stack+0x43/0xd0 [ 397.208868] kasan_slab_free+0x71/0xc0 [ 397.212724] kmem_cache_free+0x77/0x280 [ 397.216667] userfaultfd_ctx_put+0x50c/0x740 [ 397.221042] userfaultfd_event_wait_completion+0x754/0x910 [ 397.226632] dup_userfaultfd_complete+0x2de/0x480 [ 397.231545] copy_mm+0xe9b/0x1310 [ 397.234967] copy_process.part.36+0x1eae/0x4af0 [ 397.239601] _do_fork+0x1ef/0xfe0 [ 397.243024] SyS_clone+0x37/0x50 [ 397.246365] do_syscall_64+0x26c/0x8c0 [ 397.250222] return_from_SYSCALL_64+0x0/0x7a [ 397.254596] [ 397.256196] The buggy address belongs to the object at ffff8801c90cb200 [ 397.256196] which belongs to the cache userfaultfd_ctx_cache of size 400 [ 397.269688] The buggy address is located 392 bytes inside of [ 397.269688] 400-byte region [ffff8801c90cb200, ffff8801c90cb390) [ 397.281530] The buggy address belongs to the page: [ 397.286428] page:ffffea00072432c0 count:1 mapcount:0 mapping:ffff8801c90cb000 index:0xffff8801c91d5880 [ 397.295843] flags: 0x200000000000100(slab) [ 397.300050] raw: 0200000000000100 ffff8801c90cb000 ffff8801c91d5880 0000000100000008 [ 397.307901] raw: ffffea000725b7a0 ffff8801d5690250 ffff8801d56f8c00 0000000000000000 [ 397.315748] page dumped because: kasan: bad access detected [ 397.321426] [ 397.323023] Memory state around the buggy address: [ 397.327920] ffff8801c90cb280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 397.335246] ffff8801c90cb300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 397.342575] >ffff8801c90cb380: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 397.349901] ^ [ 397.353494] ffff8801c90cb400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 397.360823] ffff8801c90cb480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 397.368156] ================================================================== [ 397.375483] Disabling lock debugging due to kernel taint [ 397.380980] Kernel panic - not syncing: panic_on_warn set ... [ 397.380980] [ 397.388315] CPU: 0 PID: 4268 Comm: syz-executor0 Tainted: G B 4.13.0-mm1+ #7 [ 397.396591] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 397.405907] Call Trace: [ 397.408464] dump_stack+0x194/0x257 [ 397.412058] ? arch_local_irq_restore+0x53/0x53 [ 397.416693] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 397.421416] ? userfaultfd_release+0x4f0/0x6e0 [ 397.425968] panic+0x1e4/0x417 [ 397.429127] ? __warn+0x1d9/0x1d9 [ 397.432551] ? userfaultfd_release+0x5c1/0x6e0 [ 397.437097] kasan_end_report+0x50/0x50 [ 397.441035] kasan_report+0x137/0x340 [ 397.444804] ? userfaultfd_event_wait_completion+0x910/0x910 [ 397.450567] __asan_report_load8_noabort+0x14/0x20 [ 397.455459] userfaultfd_release+0x5c1/0x6e0 [ 397.459832] ? fcntl_setlk+0x10d0/0x10d0 [ 397.463858] ? userfaultfd_event_wait_completion+0x910/0x910 [ 397.469622] ? fsnotify+0x1af0/0x1af0 [ 397.473395] ? __might_sleep+0x95/0x190 [ 397.477335] ? userfaultfd_event_wait_completion+0x910/0x910 [ 397.483096] __fput+0x333/0x7f0 [ 397.486343] ? fput+0x140/0x140 [ 397.489591] ? _raw_spin_unlock_irq+0x27/0x70 [ 397.494054] ____fput+0x15/0x20 [ 397.497298] task_work_run+0x199/0x270 [ 397.501150] ? task_work_cancel+0x210/0x210 [ 397.505436] ? _raw_spin_unlock+0x22/0x30 [ 397.509550] ? switch_task_namespaces+0x87/0xc0 [ 397.514187] do_exit+0xa52/0x1b40 [ 397.517609] ? do_raw_spin_trylock+0x190/0x190 [ 397.522154] ? do_raw_spin_trylock+0x190/0x190 [ 397.526706] ? mm_update_next_owner+0x930/0x930 [ 397.531342] ? trace_hardirqs_off+0xd/0x10 [ 397.535553] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 397.540621] ? try_to_wake_up+0x115/0x1850 [ 397.544822] ? check_noncircular+0x20/0x20 [ 397.549034] ? migrate_swap_stop+0x970/0x970 [ 397.553409] ? lock_downgrade+0x990/0x990 [ 397.557528] ? find_held_lock+0x39/0x1d0 [ 397.561562] ? lock_downgrade+0x990/0x990 [ 397.565675] ? __handle_mm_fault+0x39c0/0x39c0 [ 397.570224] ? vmacache_find+0x61/0x270 [ 397.574162] ? retint_kernel+0x10/0x10 [ 397.578016] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 397.582999] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 397.587725] ? retint_kernel+0x10/0x10 [ 397.591594] ? _raw_spin_unlock_irq+0x56/0x70 [ 397.596055] do_group_exit+0x149/0x400 [ 397.599907] ? lockdep_sys_exit+0x47/0xf0 [ 397.604018] ? SyS_exit+0x30/0x30 [ 397.607436] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 397.612431] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 397.617153] SyS_exit_group+0x1d/0x20 [ 397.620920] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 397.625648] RIP: 0033:0x4520a9 [ 397.628804] RSP: 002b:00007ffd274e6a38 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 [ 397.636476] RAX: ffffffffffffffda RBX: 0000000001096914 RCX: 00000000004520a9 [ 397.643712] RDX: 00000000004520a9 RSI: 0000000000760618 RDI: 0000000000000000 [ 397.650948] RBP: 0000000000000082 R08: 00000000007180b0 R09: 00000000000010a7 [ 397.658184] R10: 0000000000760610 R11: 0000000000000202 R12: 0000000000000045 [ 397.665418] R13: 00000000007180b0 R14: 00000000007180dc R15: 0000000000000016 [ 397.672704] Dumping ftrace buffer: [ 397.676213] (ftrace buffer empty) [ 397.679890] Kernel Offset: disabled [ 397.683484] Rebooting in 86400 seconds..