[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.350274] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.232573] random: sshd: uninitialized urandom read (32 bytes read) [ 23.531813] random: sshd: uninitialized urandom read (32 bytes read) [ 24.416812] random: sshd: uninitialized urandom read (32 bytes read) [ 43.690596] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.25' (ECDSA) to the list of known hosts. [ 49.531421] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 54.298313] ================================================================== [ 54.305788] BUG: KASAN: use-after-free in _free_event+0x48d/0x1440 [ 54.312088] Write of size 4 at addr ffff8801ab6360e0 by task syz-executor205/5237 [ 54.319681] [ 54.321308] CPU: 1 PID: 5237 Comm: syz-executor205 Not tainted 4.18.0-rc4+ #139 [ 54.328733] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.338066] Call Trace: [ 54.340637] dump_stack+0x1c9/0x2b4 [ 54.344245] ? dump_stack_print_info.cold.2+0x52/0x52 [ 54.349416] ? printk+0xa7/0xcf [ 54.352673] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 54.357411] ? _free_event+0x48d/0x1440 [ 54.361362] print_address_description+0x6c/0x20b [ 54.366189] ? _free_event+0x48d/0x1440 [ 54.370144] kasan_report.cold.7+0x242/0x2fe [ 54.374537] check_memory_region+0x13e/0x1b0 [ 54.378935] kasan_check_write+0x14/0x20 [ 54.382981] _free_event+0x48d/0x1440 [ 54.386772] ? ring_buffer_attach+0x840/0x840 [ 54.391244] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 54.396249] ? kasan_check_write+0x14/0x20 [ 54.400477] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 54.405406] ? event_sched_out.isra.99+0xf10/0xf10 [ 54.410321] ? wait_for_completion+0x8d0/0x8d0 [ 54.414887] ? event_sched_out.isra.99+0xf10/0xf10 [ 54.419799] free_event+0xb4/0x180 [ 54.423323] ? _free_event+0x1440/0x1440 [ 54.427371] perf_event_release_kernel+0x7d5/0x1050 [ 54.432369] ? put_event+0x60/0x60 [ 54.435905] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 54.440299] ? trace_hardirqs_on+0x10/0x10 [ 54.444516] ? is_bpf_text_address+0xd7/0x170 [ 54.448997] ? kernel_text_address+0x79/0xf0 [ 54.453383] ? __kernel_text_address+0xd/0x40 [ 54.457862] ? __save_stack_trace+0x8d/0xf0 [ 54.462167] ? graph_lock+0x170/0x170 [ 54.465948] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.471468] ? locks_remove_file+0x402/0x5c0 [ 54.475856] ? fcntl_setlk+0x1040/0x1040 [ 54.479895] ? do_exit+0xf69/0x2750 [ 54.483503] ? fsnotify_first_mark+0x350/0x350 [ 54.488077] ? __fsnotify_parent+0xcc/0x420 [ 54.492378] ? fsnotify+0x14e0/0x14e0 [ 54.496171] ? perf_event_release_kernel+0x1050/0x1050 [ 54.501431] perf_release+0x37/0x50 [ 54.505041] __fput+0x355/0x8b0 [ 54.508301] ? fput+0x1a0/0x1a0 [ 54.511563] ? _raw_spin_unlock_irq+0x27/0x70 [ 54.516035] ____fput+0x15/0x20 [ 54.519298] task_work_run+0x1ec/0x2a0 [ 54.523164] ? task_work_cancel+0x250/0x250 [ 54.527466] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 54.532979] ? switch_task_namespaces+0xa2/0xd0 [ 54.537629] do_exit+0x1b08/0x2750 [ 54.541149] ? mm_update_next_owner+0x9a0/0x9a0 [ 54.545795] ? profiling_store+0xd0/0xd0 [ 54.549840] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 54.554836] ? do_coredump+0x477/0x3fff [ 54.558793] ? unwind_get_return_address+0x61/0xa0 [ 54.563705] ? __save_stack_trace+0x8d/0xf0 [ 54.568010] ? dump_align+0xa0/0xa0 [ 54.571625] ? save_stack+0xa9/0xd0 [ 54.575231] ? save_stack+0x43/0xd0 [ 54.578835] ? __kasan_slab_free+0x11a/0x170 [ 54.583221] ? kasan_slab_free+0xe/0x10 [ 54.587174] ? kmem_cache_free+0x86/0x2d0 [ 54.591312] ? __sigqueue_free.part.28+0x7d/0xa0 [ 54.596042] ? __dequeue_signal+0x530/0x7d0 [ 54.600337] ? dequeue_signal+0xbc/0x620 [ 54.604375] ? get_signal+0x3f1/0x1970 [ 54.608245] ? do_signal+0x9c/0x21c0 [ 54.611936] ? exit_to_usermode_loop+0x2e0/0x370 [ 54.616670] ? prepare_exit_to_usermode+0x342/0x3b0 [ 54.621670] ? kasan_check_read+0x11/0x20 [ 54.625886] ? do_raw_spin_unlock+0xa7/0x2f0 [ 54.630271] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 54.634831] ? kasan_check_write+0x14/0x20 [ 54.639046] ? graph_lock+0x170/0x170 [ 54.642825] ? trace_hardirqs_off+0xd/0x10 [ 54.647041] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 54.652132] ? __lock_is_held+0xb5/0x140 [ 54.656174] ? __sigqueue_free.part.28+0x7d/0xa0 [ 54.660909] ? graph_lock+0x170/0x170 [ 54.664689] ? __sigqueue_free.part.28+0x7d/0xa0 [ 54.669439] ? rcu_read_lock_sched_held+0x108/0x120 [ 54.674443] ? kmem_cache_free+0x25c/0x2d0 [ 54.678675] ? __sigqueue_free.part.28+0x7d/0xa0 [ 54.683417] ? find_held_lock+0x36/0x1c0 [ 54.687465] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.693000] ? proc_coredump_connector+0x4d0/0x610 [ 54.697909] ? lock_downgrade+0x8f0/0x8f0 [ 54.702045] ? proc_comm_connector+0x500/0x500 [ 54.706605] do_group_exit+0x177/0x440 [ 54.710475] ? __ia32_sys_exit+0x50/0x50 [ 54.714532] ? _raw_spin_unlock_irq+0x27/0x70 [ 54.719006] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 54.724004] get_signal+0x88e/0x1970 [ 54.727700] ? ptrace_notify+0x130/0x130 [ 54.731739] ? force_sig_info+0x281/0x310 [ 54.735873] ? force_sig_info_fault.constprop.32+0x2b7/0x4a0 [ 54.741651] ? is_prefetch.isra.29+0x530/0x530 [ 54.746310] do_signal+0x9c/0x21c0 [ 54.749835] ? setup_sigcontext+0x7d0/0x7d0 [ 54.754138] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.759848] ? bad_area+0x69/0x80 [ 54.763298] ? __do_page_fault+0x449/0xe50 [ 54.767523] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 54.772086] ? exit_to_usermode_loop+0x8c/0x370 [ 54.776746] exit_to_usermode_loop+0x2e0/0x370 [ 54.781311] ? syscall_slow_exit_work+0x500/0x500 [ 54.786139] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.791656] ? syscall_return_slowpath+0x31d/0x5e0 [ 54.796570] prepare_exit_to_usermode+0x342/0x3b0 [ 54.801391] ? perf_trace_sys_enter+0xb10/0xb10 [ 54.806036] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 54.810858] ? page_fault+0x8/0x30 [ 54.814377] retint_user+0x8/0x18 [ 54.817803] RIP: 0033: (null) [ 54.821769] Code: Bad RIP value. [ 54.825127] RSP: 002b:0000000020000048 EFLAGS: 00010217 [ 54.830468] RAX: 0000000000000000 RBX: 00000000006dbc24 RCX: 0000000000445d89 [ 54.837715] RDX: 0000000020000100 RSI: 0000000020000040 RDI: 0000000000000000 [ 54.844962] RBP: 0000000000000000 R08: 0000000020000080 R09: 0000000000000000 [ 54.852210] R10: 0000000020000000 R11: 0000000000000246 R12: 00000000006dbc20 [ 54.859473] R13: 0030656c69662f2e R14: 0000004000008912 R15: 0000000000000006 [ 54.866739] [ 54.868343] Allocated by task 5236: [ 54.871964] save_stack+0x43/0xd0 [ 54.875410] kasan_kmalloc+0xc4/0xe0 [ 54.879102] kasan_slab_alloc+0x12/0x20 [ 54.883055] kmem_cache_alloc_node+0x144/0x780 [ 54.887616] copy_process.part.39+0x16b5/0x7220 [ 54.892281] _do_fork+0x291/0x12a0 [ 54.895799] __x64_sys_clone+0xbf/0x150 [ 54.899752] do_syscall_64+0x1b9/0x820 [ 54.903629] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.908791] [ 54.910392] Freed by task 5236: [ 54.913651] save_stack+0x43/0xd0 [ 54.917082] __kasan_slab_free+0x11a/0x170 [ 54.921294] kasan_slab_free+0xe/0x10 [ 54.925070] kmem_cache_free+0x86/0x2d0 [ 54.929023] free_task+0x16e/0x1f0 [ 54.932541] copy_process.part.39+0x15c9/0x7220 [ 54.937187] _do_fork+0x291/0x12a0 [ 54.940703] __x64_sys_clone+0xbf/0x150 [ 54.944864] do_syscall_64+0x1b9/0x820 [ 54.948741] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.953902] [ 54.955510] The buggy address belongs to the object at ffff8801ab6360c0 [ 54.955510] which belongs to the cache task_struct of size 5952 [ 54.968241] The buggy address is located 32 bytes inside of [ 54.968241] 5952-byte region [ffff8801ab6360c0, ffff8801ab637800) [ 54.980088] The buggy address belongs to the page: [ 54.984998] page:ffffea0006ad8d80 count:1 mapcount:0 mapping:ffff8801da94b200 index:0x0 compound_mapcount: 0 [ 54.994945] flags: 0x2fffc0000008100(slab|head) [ 54.999597] raw: 02fffc0000008100 ffffea0006ad9008 ffffea00075f5888 ffff8801da94b200 [ 55.007457] raw: 0000000000000000 ffff8801ab6360c0 0000000100000001 0000000000000000 [ 55.015314] page dumped because: kasan: bad access detected [ 55.020997] [ 55.022599] Memory state around the buggy address: [ 55.027504] ffff8801ab635f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 55.034837] ffff8801ab636000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 55.042176] >ffff8801ab636080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 55.049510] ^ [ 55.055976] ffff8801ab636100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.063320] ffff8801ab636180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 55.070654] ================================================================== [ 55.077985] Disabling lock debugging due to kernel taint [ 55.083549] Kernel panic - not syncing: panic_on_warn set ... [ 55.083549] [ 55.090896] CPU: 1 PID: 5237 Comm: syz-executor205 Tainted: G B 4.18.0-rc4+ #139 [ 55.099715] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.109043] Call Trace: [ 55.111614] dump_stack+0x1c9/0x2b4 [ 55.115223] ? dump_stack_print_info.cold.2+0x52/0x52 [ 55.120395] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.125132] panic+0x238/0x4e7 [ 55.128300] ? add_taint.cold.5+0x16/0x16 [ 55.132426] ? do_raw_spin_unlock+0xa7/0x2f0 [ 55.136811] ? do_raw_spin_unlock+0xa7/0x2f0 [ 55.141198] ? _free_event+0x48d/0x1440 [ 55.145148] kasan_end_report+0x47/0x4f [ 55.149097] kasan_report.cold.7+0x76/0x2fe [ 55.153396] check_memory_region+0x13e/0x1b0 [ 55.157781] kasan_check_write+0x14/0x20 [ 55.161817] _free_event+0x48d/0x1440 [ 55.165597] ? ring_buffer_attach+0x840/0x840 [ 55.170068] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 55.175058] ? kasan_check_write+0x14/0x20 [ 55.179283] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 55.184188] ? event_sched_out.isra.99+0xf10/0xf10 [ 55.189092] ? wait_for_completion+0x8d0/0x8d0 [ 55.193652] ? event_sched_out.isra.99+0xf10/0xf10 [ 55.198560] free_event+0xb4/0x180 [ 55.202079] ? _free_event+0x1440/0x1440 [ 55.206120] perf_event_release_kernel+0x7d5/0x1050 [ 55.211110] ? put_event+0x60/0x60 [ 55.214628] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 55.219019] ? trace_hardirqs_on+0x10/0x10 [ 55.223231] ? is_bpf_text_address+0xd7/0x170 [ 55.227707] ? kernel_text_address+0x79/0xf0 [ 55.232099] ? __kernel_text_address+0xd/0x40 [ 55.236572] ? __save_stack_trace+0x8d/0xf0 [ 55.240882] ? graph_lock+0x170/0x170 [ 55.244662] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.250178] ? locks_remove_file+0x402/0x5c0 [ 55.254566] ? fcntl_setlk+0x1040/0x1040 [ 55.258603] ? do_exit+0xf69/0x2750 [ 55.262409] ? fsnotify_first_mark+0x350/0x350 [ 55.266966] ? __fsnotify_parent+0xcc/0x420 [ 55.271261] ? fsnotify+0x14e0/0x14e0 [ 55.275049] ? perf_event_release_kernel+0x1050/0x1050 [ 55.280303] perf_release+0x37/0x50 [ 55.283909] __fput+0x355/0x8b0 [ 55.287168] ? fput+0x1a0/0x1a0 [ 55.290427] ? _raw_spin_unlock_irq+0x27/0x70 [ 55.294903] ____fput+0x15/0x20 [ 55.298170] task_work_run+0x1ec/0x2a0 [ 55.302036] ? task_work_cancel+0x250/0x250 [ 55.306339] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 55.311854] ? switch_task_namespaces+0xa2/0xd0 [ 55.316501] do_exit+0x1b08/0x2750 [ 55.320018] ? mm_update_next_owner+0x9a0/0x9a0 [ 55.324663] ? profiling_store+0xd0/0xd0 [ 55.328708] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 55.333706] ? do_coredump+0x477/0x3fff [ 55.337660] ? unwind_get_return_address+0x61/0xa0 [ 55.342581] ? __save_stack_trace+0x8d/0xf0 [ 55.346883] ? dump_align+0xa0/0xa0 [ 55.350490] ? save_stack+0xa9/0xd0 [ 55.354101] ? save_stack+0x43/0xd0 [ 55.357706] ? __kasan_slab_free+0x11a/0x170 [ 55.362091] ? kasan_slab_free+0xe/0x10 [ 55.366041] ? kmem_cache_free+0x86/0x2d0 [ 55.370166] ? __sigqueue_free.part.28+0x7d/0xa0 [ 55.374896] ? __dequeue_signal+0x530/0x7d0 [ 55.379390] ? dequeue_signal+0xbc/0x620 [ 55.383429] ? get_signal+0x3f1/0x1970 [ 55.387314] ? do_signal+0x9c/0x21c0 [ 55.391009] ? exit_to_usermode_loop+0x2e0/0x370 [ 55.395741] ? prepare_exit_to_usermode+0x342/0x3b0 [ 55.400745] ? kasan_check_read+0x11/0x20 [ 55.404872] ? do_raw_spin_unlock+0xa7/0x2f0 [ 55.409257] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 55.413819] ? kasan_check_write+0x14/0x20 [ 55.418128] ? graph_lock+0x170/0x170 [ 55.421911] ? trace_hardirqs_off+0xd/0x10 [ 55.426125] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 55.431209] ? __lock_is_held+0xb5/0x140 [ 55.435254] ? __sigqueue_free.part.28+0x7d/0xa0 [ 55.439986] ? graph_lock+0x170/0x170 [ 55.443782] ? __sigqueue_free.part.28+0x7d/0xa0 [ 55.448519] ? rcu_read_lock_sched_held+0x108/0x120 [ 55.453513] ? kmem_cache_free+0x25c/0x2d0 [ 55.457723] ? __sigqueue_free.part.28+0x7d/0xa0 [ 55.462459] ? find_held_lock+0x36/0x1c0 [ 55.466498] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.472015] ? proc_coredump_connector+0x4d0/0x610 [ 55.476924] ? lock_downgrade+0x8f0/0x8f0 [ 55.481053] ? proc_comm_connector+0x500/0x500 [ 55.485612] do_group_exit+0x177/0x440 [ 55.489478] ? __ia32_sys_exit+0x50/0x50 [ 55.493515] ? _raw_spin_unlock_irq+0x27/0x70 [ 55.497992] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 55.502990] get_signal+0x88e/0x1970 [ 55.506685] ? ptrace_notify+0x130/0x130 [ 55.510724] ? force_sig_info+0x281/0x310 [ 55.514865] ? force_sig_info_fault.constprop.32+0x2b7/0x4a0 [ 55.520646] ? is_prefetch.isra.29+0x530/0x530 [ 55.525211] do_signal+0x9c/0x21c0 [ 55.528732] ? setup_sigcontext+0x7d0/0x7d0 [ 55.533037] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.538554] ? bad_area+0x69/0x80 [ 55.541985] ? __do_page_fault+0x449/0xe50 [ 55.546201] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 55.550771] ? exit_to_usermode_loop+0x8c/0x370 [ 55.555419] exit_to_usermode_loop+0x2e0/0x370 [ 55.559983] ? syscall_slow_exit_work+0x500/0x500 [ 55.564813] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 55.570327] ? syscall_return_slowpath+0x31d/0x5e0 [ 55.575233] prepare_exit_to_usermode+0x342/0x3b0 [ 55.580052] ? perf_trace_sys_enter+0xb10/0xb10 [ 55.584696] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 55.589523] ? page_fault+0x8/0x30 [ 55.593202] retint_user+0x8/0x18 [ 55.596629] RIP: 0033: (null) [ 55.600485] Code: Bad RIP value. [ 55.603839] RSP: 002b:0000000020000048 EFLAGS: 00010217 [ 55.609177] RAX: 0000000000000000 RBX: 00000000006dbc24 RCX: 0000000000445d89 [ 55.616724] RDX: 0000000020000100 RSI: 0000000020000040 RDI: 0000000000000000 [ 55.623971] RBP: 0000000000000000 R08: 0000000020000080 R09: 0000000000000000 [ 55.631221] R10: 0000000020000000 R11: 0000000000000246 R12: 00000000006dbc20 [ 55.638473] R13: 0030656c69662f2e R14: 0000004000008912 R15: 0000000000000006 [ 55.646119] Dumping ftrace buffer: [ 55.649635] (ftrace buffer empty) [ 55.653321] Kernel Offset: disabled [ 55.656925] Rebooting in 86400 seconds..