[....] 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 2017/10/26 09:20:52 parsed 1 programs 2017/10/26 09:20:52 executed programs: 0 syzkaller login: [ 19.045170] ================================================================== [ 19.045705] BUG: KASAN: use-after-free in __lock_acquire+0x3c9f/0x3d50 [ 19.046132] Read of size 8 at addr ffff88006cd9b668 by task syz-executor0/3047 [ 19.046579] [ 19.046685] CPU: 0 PID: 3047 Comm: syz-executor0 Not tainted 4.14.0-rc5-next-20171018+ #8 [ 19.047250] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 19.047887] Call Trace: [ 19.048089] dump_stack+0x194/0x257 [ 19.048376] ? arch_local_irq_restore+0x53/0x53 [ 19.048778] ? show_regs_print_info+0x65/0x65 [ 19.049161] ? print_irqtrace_events+0x270/0x270 [ 19.049464] ? print_irqtrace_events+0x270/0x270 [ 19.049797] ? __lock_acquire+0x3c9f/0x3d50 [ 19.050131] print_address_description+0x73/0x250 [ 19.050491] ? __lock_acquire+0x3c9f/0x3d50 [ 19.050822] kasan_report+0x25b/0x340 [ 19.051105] __asan_report_load8_noabort+0x14/0x20 [ 19.051469] __lock_acquire+0x3c9f/0x3d50 [ 19.051776] ? exit_pi_state_list+0x369/0x7a0 [ 19.052116] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.052505] ? __lock_acquire+0x6aa/0x3d50 [ 19.052784] ? __lock_acquire+0x6aa/0x3d50 [ 19.053051] ? __lock_acquire+0x6aa/0x3d50 [ 19.053317] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.053651] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.054253] ? check_noncircular+0x20/0x20 [ 19.054504] ? osq_unlock+0x350/0x350 [ 19.054729] ? __lock_acquire+0x6aa/0x3d50 [ 19.054980] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.055285] ? check_noncircular+0x20/0x20 [ 19.055534] ? print_irqtrace_events+0x270/0x270 [ 19.055815] ? check_noncircular+0x20/0x20 [ 19.056067] ? perf_event_sync_stat+0x5c0/0x5c0 [ 19.056341] ? __lock_is_held+0xb6/0x140 [ 19.056581] ? __perf_event_task_sched_in+0x200/0xc20 [ 19.056885] ? find_held_lock+0x35/0x1d0 [ 19.057133] lock_acquire+0x1d5/0x580 [ 19.057357] ? lock_acquire+0x1d5/0x580 [ 19.057591] ? exit_pi_state_list+0x369/0x7a0 [ 19.057981] ? lock_downgrade+0x990/0x990 [ 19.058269] ? lock_release+0xa40/0xa40 [ 19.058504] ? do_raw_spin_trylock+0x190/0x190 [ 19.058774] ? lock_downgrade+0x990/0x990 [ 19.059023] _raw_spin_lock_irq+0x5e/0x80 [ 19.059269] ? exit_pi_state_list+0x369/0x7a0 [ 19.059599] exit_pi_state_list+0x369/0x7a0 [ 19.059918] ? futex_wait_requeue_pi.constprop.19+0x1300/0x1300 [ 19.060353] ? lock_release+0xa40/0xa40 [ 19.060644] ? trace_event_raw_event_sched_switch+0x8a0/0x8a0 [ 19.061170] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 19.061644] ? __might_sleep+0x95/0x190 [ 19.062017] ? __might_fault+0x188/0x1d0 [ 19.062393] ? do_raw_spin_trylock+0x190/0x190 [ 19.062815] mm_release+0x46d/0x590 [ 19.063078] ? do_raw_spin_trylock+0x190/0x190 [ 19.063461] ? mm_access+0x140/0x140 [ 19.063767] ? _raw_spin_unlock_irq+0x27/0x70 [ 19.064178] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 19.064553] ? trace_hardirqs_on+0xd/0x10 [ 19.064798] ? _raw_spin_unlock_irq+0x27/0x70 [ 19.065064] ? acct_collect+0x637/0x800 [ 19.065301] do_exit+0x481/0x1ad0 [ 19.065510] ? mm_update_next_owner+0x930/0x930 [ 19.065829] ? trace_event_raw_event_sched_switch+0x8a0/0x8a0 [ 19.066243] ? rcu_note_context_switch+0x710/0x710 [ 19.066532] ? futex_wait_setup+0x14a/0x3d0 [ 19.066788] ? __might_sleep+0x95/0x190 [ 19.067024] ? find_held_lock+0x35/0x1d0 [ 19.067264] ? futex_wait+0x402/0x990 [ 19.067489] ? lock_downgrade+0x990/0x990 [ 19.067733] ? do_raw_spin_trylock+0x190/0x190 [ 19.068002] ? check_noncircular+0x20/0x20 [ 19.068252] ? futex_wake+0x680/0x680 [ 19.068477] ? mmdrop+0x18/0x30 [ 19.068672] ? drop_futex_key_refs.isra.13+0x63/0xa0 [ 19.068971] ? futex_wait+0x69e/0x990 [ 19.069197] ? find_held_lock+0x35/0x1d0 [ 19.069437] ? get_signal+0x7ae/0x16d0 [ 19.069667] ? lock_downgrade+0x990/0x990 [ 19.070010] do_group_exit+0x149/0x400 [ 19.070299] ? __lock_is_held+0xb6/0x140 [ 19.070544] ? SyS_exit+0x30/0x30 [ 19.070749] ? _raw_spin_unlock_irq+0x27/0x70 [ 19.071037] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 19.071500] get_signal+0x73f/0x16d0 [ 19.071844] ? ptrace_notify+0x130/0x130 [ 19.072217] ? vma_wants_writenotify+0x3b0/0x3b0 [ 19.072589] ? vma_link+0xe9/0x170 [ 19.072922] ? exit_robust_list+0x240/0x240 [ 19.073555] ? find_held_lock+0x35/0x1d0 [ 19.073867] do_signal+0x94/0x1ee0 [ 19.074079] ? vm_mmap_pgoff+0x1ed/0x280 [ 19.074318] ? should_fail+0x23b/0xa40 [ 19.074548] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 19.074860] ? setup_sigcontext+0x7d0/0x7d0 [ 19.075114] ? find_held_lock+0x35/0x1d0 [ 19.075354] ? lock_downgrade+0x990/0x990 [ 19.075598] ? down_read_killable+0x180/0x180 [ 19.075873] ? lock_release+0xa40/0xa40 [ 19.076107] ? trace_event_raw_event_sched_switch+0x8a0/0x8a0 [ 19.076450] ? vm_mmap_pgoff+0x1fc/0x280 [ 19.076692] ? exit_to_usermode_loop+0x8c/0x310 [ 19.076979] exit_to_usermode_loop+0x214/0x310 [ 19.077258] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 19.077581] ? kasan_check_write+0x14/0x20 [ 19.077942] syscall_return_slowpath+0x42f/0x510 [ 19.078374] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 19.078828] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 19.079320] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 19.079722] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 19.080082] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 19.080427] RIP: 0033:0x447c89 [ 19.080656] RSP: 002b:00007fb972edcce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca [ 19.081218] RAX: fffffffffffffe00 RBX: 00000000007481b8 RCX: 0000000000447c89 [ 19.081759] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000007481b8 [ 19.082280] RBP: 00000000007481b8 R08: 0000000000000000 R09: 0000000000748190 [ 19.082800] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 19.083320] R13: 0000000000000000 R14: 00007fb972edd9c0 R15: 00007fb972edd700 [ 19.083842] [ 19.083961] Allocated by task 3048: [ 19.084228] save_stack+0x43/0xd0 [ 19.084486] kasan_kmalloc+0xad/0xe0 [ 19.084755] kmem_cache_alloc_trace+0x136/0x750 [ 19.085093] refill_pi_state_cache.part.6+0xa5/0x2f0 [ 19.085475] futex_requeue+0x1887/0x2370 [ 19.085773] do_futex+0x7f5/0x20d0 [ 19.086029] SyS_futex+0x260/0x390 [ 19.086317] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 19.086747] [ 19.086894] Freed by task 3046: [ 19.087191] save_stack+0x43/0xd0 [ 19.087502] kasan_slab_free+0x71/0xc0 [ 19.087852] kfree+0xca/0x250 [ 19.088132] put_pi_state+0x3f4/0x560 [ 19.088475] unqueue_me_pi+0x4a/0xc0 [ 19.088811] futex_wait_requeue_pi.constprop.19+0xc7f/0x1300 [ 19.089332] do_futex+0x825/0x20d0 [ 19.089650] SyS_futex+0x260/0x390 [ 19.089976] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 19.090402] [ 19.090550] The buggy address belongs to the object at ffff88006cd9b640 [ 19.090550] which belongs to the cache kmalloc-256 of size 256 [ 19.091559] The buggy address is located 40 bytes inside of [ 19.091559] 256-byte region [ffff88006cd9b640, ffff88006cd9b740) [ 19.092364] The buggy address belongs to the page: [ 19.092705] page:ffffea0001b366c0 count:1 mapcount:0 mapping:ffff88006cd9b000 index:0xffff88006cd9b500 [ 19.093442] flags: 0x500000000000100(slab) [ 19.093741] raw: 0500000000000100 ffff88006cd9b000 ffff88006cd9b500 0000000100000007 [ 19.094380] raw: ffffea0001a5df60 ffffea0001b4d660 ffff88003e8007c0 0000000000000000 [ 19.095062] page dumped because: kasan: bad access detected [ 19.095582] [ 19.095729] Memory state around the buggy address: [ 19.096179] ffff88006cd9b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 19.096846] ffff88006cd9b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 19.097359] >ffff88006cd9b600: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 19.098103] ^ [ 19.098581] ffff88006cd9b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 19.099230] ffff88006cd9b700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 19.099896] ================================================================== [ 19.100563] Disabling lock debugging due to kernel taint [ 19.101058] Kernel panic - not syncing: panic_on_warn set ... [ 19.101058] [ 19.101741] CPU: 0 PID: 3047 Comm: syz-executor0 Tainted: G B 4.14.0-rc5-next-20171018+ #8 [ 19.102396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 19.102871] Call Trace: [ 19.103029] dump_stack+0x194/0x257 [ 19.103245] ? arch_local_irq_restore+0x53/0x53 [ 19.103519] ? kasan_end_report+0x32/0x50 [ 19.103764] ? lock_downgrade+0x990/0x990 [ 19.104009] ? vsnprintf+0x1ed/0x1900 [ 19.104233] ? __lock_acquire+0x3c50/0x3d50 [ 19.104487] panic+0x1e4/0x41c [ 19.104677] ? refcount_error_report+0x214/0x214 [ 19.104957] ? add_taint+0x40/0x50 [ 19.105166] ? add_taint+0x1c/0x50 [ 19.105385] ? __lock_acquire+0x3c9f/0x3d50 [ 19.105641] kasan_end_report+0x50/0x50 [ 19.106017] kasan_report+0x144/0x340 [ 19.106364] __asan_report_load8_noabort+0x14/0x20 [ 19.106812] __lock_acquire+0x3c9f/0x3d50 [ 19.107205] ? exit_pi_state_list+0x369/0x7a0 [ 19.107613] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.108111] ? __lock_acquire+0x6aa/0x3d50 [ 19.108495] ? __lock_acquire+0x6aa/0x3d50 [ 19.108879] ? __lock_acquire+0x6aa/0x3d50 [ 19.109264] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.109745] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.110220] ? check_noncircular+0x20/0x20 [ 19.110605] ? osq_unlock+0x350/0x350 [ 19.110953] ? __lock_acquire+0x6aa/0x3d50 [ 19.111335] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 19.111814] ? check_noncircular+0x20/0x20 [ 19.112206] ? print_irqtrace_events+0x270/0x270 [ 19.112646] ? check_noncircular+0x20/0x20 [ 19.113039] ? perf_event_sync_stat+0x5c0/0x5c0 [ 19.113468] ? __lock_is_held+0xb6/0x140 [ 19.113847] ? __perf_event_task_sched_in+0x200/0xc20 [ 19.114326] ? find_held_lock+0x35/0x1d0 [ 19.114701] lock_acquire+0x1d5/0x580 [ 19.115050] ? lock_acquire+0x1d5/0x580 [ 19.115345] ? exit_pi_state_list+0x369/0x7a0 [ 19.115674] ? lock_downgrade+0x990/0x990 [ 19.116217] ? lock_release+0xa40/0xa40 [ 19.116451] ? do_raw_spin_trylock+0x190/0x190 [ 19.116718] ? lock_downgrade+0x990/0x990 [ 19.116965] _raw_spin_lock_irq+0x5e/0x80 [ 19.117208] ? exit_pi_state_list+0x369/0x7a0 [ 19.117471] exit_pi_state_list+0x369/0x7a0 [ 19.117750] ? futex_wait_requeue_pi.constprop.19+0x1300/0x1300 [ 19.118307] ? lock_release+0xa40/0xa40 [ 19.118674] ? trace_event_raw_event_sched_switch+0x8a0/0x8a0 [ 19.119212] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 19.119677] ? __might_sleep+0x95/0x190 [ 19.120041] ? __might_fault+0x188/0x1d0 [ 19.120418] ? do_raw_spin_trylock+0x190/0x190 [ 19.120840] mm_release+0x46d/0x590 [ 19.121173] ? do_raw_spin_trylock+0x190/0x190 [ 19.121591] ? mm_access+0x140/0x140 [ 19.121935] ? _raw_spin_unlock_irq+0x27/0x70 [ 19.122249] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 19.122595] ? trace_hardirqs_on+0xd/0x10 [ 19.122915] ? _raw_spin_unlock_irq+0x27/0x70 [ 19.123279] ? acct_collect+0x637/0x800 [ 19.123638] do_exit+0x481/0x1ad0 [ 19.123942] ? mm_update_next_owner+0x930/0x930 [ 19.124369] ? trace_event_raw_event_sched_switch+0x8a0/0x8a0 [ 19.124780] ? rcu_note_context_switch+0x710/0x710 [ 19.125129] ? futex_wait_setup+0x14a/0x3d0 [ 19.125434] ? __might_sleep+0x95/0x190 [ 19.125793] ? find_held_lock+0x35/0x1d0 [ 19.126164] ? futex_wait+0x402/0x990 [ 19.126510] ? lock_downgrade+0x990/0x990 [ 19.126889] ? do_raw_spin_trylock+0x190/0x190 [ 19.127296] ? check_noncircular+0x20/0x20 [ 19.127698] ? futex_wake+0x680/0x680 [ 19.128063] ? mmdrop+0x18/0x30 [ 19.128360] ? drop_futex_key_refs.isra.13+0x63/0xa0 [ 19.128741] ? futex_wait+0x69e/0x990 [ 19.129109] ? find_held_lock+0x35/0x1d0 [ 19.129464] ? get_signal+0x7ae/0x16d0 [ 19.129876] ? lock_downgrade+0x990/0x990 [ 19.130201] do_group_exit+0x149/0x400 [ 19.130483] ? __lock_is_held+0xb6/0x140 [ 19.130790] ? SyS_exit+0x30/0x30 [ 19.131054] ? _raw_spin_unlock_irq+0x27/0x70 [ 19.131436] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 19.131829] get_signal+0x73f/0x16d0 [ 19.132153] ? ptrace_notify+0x130/0x130 [ 19.132514] ? vma_wants_writenotify+0x3b0/0x3b0 [ 19.132888] ? vma_link+0xe9/0x170 [ 19.133165] ? exit_robust_list+0x240/0x240 [ 19.133480] ? find_held_lock+0x35/0x1d0 [ 19.133780] do_signal+0x94/0x1ee0 [ 19.134039] ? vm_mmap_pgoff+0x1ed/0x280 [ 19.134337] ? should_fail+0x23b/0xa40 [ 19.134617] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 19.134988] ? setup_sigcontext+0x7d0/0x7d0 [ 19.135304] ? find_held_lock+0x35/0x1d0 [ 19.135600] ? lock_downgrade+0x990/0x990 [ 19.135900] ? down_read_killable+0x180/0x180 [ 19.136226] ? lock_release+0xa40/0xa40 [ 19.136520] ? trace_event_raw_event_sched_switch+0x8a0/0x8a0 [ 19.137120] ? vm_mmap_pgoff+0x1fc/0x280 [ 19.137501] ? exit_to_usermode_loop+0x8c/0x310 [ 19.138122] exit_to_usermode_loop+0x214/0x310 [ 19.138491] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 19.138957] ? kasan_check_write+0x14/0x20 [ 19.139329] syscall_return_slowpath+0x42f/0x510 [ 19.139705] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 19.140123] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 19.140573] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 19.140977] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 19.141441] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 19.141888] RIP: 0033:0x447c89 [ 19.142178] RSP: 002b:00007fb972edcce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca [ 19.142928] RAX: fffffffffffffe00 RBX: 00000000007481b8 RCX: 0000000000447c89 [ 19.143731] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000007481b8 [ 19.144444] RBP: 00000000007481b8 R08: 0000000000000000 R09: 0000000000748190 [ 19.145208] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 19.145892] R13: 0000000000000000 R14: 00007fb972edd9c0 R15: 00007fb972edd700 [ 19.146574] Dumping ftrace buffer: [ 19.146893] (ftrace buffer empty) [ 19.147229] Kernel Offset: disabled [ 19.147574] Rebooting in 86400 seconds..