[....] Starting OpenBSD Secure Shell server: sshd[ 10.660929] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 48.588419] random: sshd: uninitialized urandom read (32 bytes read) [ 49.131563] audit: type=1400 audit(1559601362.993:6): avc: denied { map } for pid=1782 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 [ 49.174093] random: sshd: uninitialized urandom read (32 bytes read) [ 49.627535] random: sshd: uninitialized urandom read (32 bytes read) [ 101.768292] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.44' (ECDSA) to the list of known hosts. [ 107.339042] random: sshd: uninitialized urandom read (32 bytes read) [ 107.428580] audit: type=1400 audit(1559601421.283:7): avc: denied { map } for pid=1830 comm="syz-executor655" path="/root/syz-executor655976253" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 executing program executing program executing program executing program executing program executing program [ 108.680034] hrtimer: interrupt took 25252 ns executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program INIT: Id "6" respawning too fast: disabled for 5 minutes INIT: Id "3" respawning too fast: disabled for 5 minutes INIT: Id "1" respawning too fast: disabled for 5 minutes INIT: Id "2" respawning too fast: disabled for 5 minutes INIT: Id "4" respawning too fast: disabled for 5 minutes INIT: Id "5" respawning too fast: disabled for 5 minutes executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 147.123772] ================================================================== [ 147.131233] BUG: KASAN: use-after-free in perf_output_read+0xe58/0xfc0 [ 147.137891] Read of size 8 at addr ffff8881ca2b2388 by task syz-executor655/2300 [ 147.145400] [ 147.147013] CPU: 0 PID: 2300 Comm: syz-executor655 Not tainted 4.14.123+ #5 [ 147.154090] Call Trace: [ 147.156663] dump_stack+0xb9/0x10e [ 147.160183] ? perf_output_read+0xe58/0xfc0 [ 147.164485] print_address_description+0x60/0x226 [ 147.169331] ? perf_output_read+0xe58/0xfc0 [ 147.173632] kasan_report.cold+0xae/0x2d5 [ 147.177775] ? perf_output_read+0xe58/0xfc0 [ 147.182083] ? perf_event_exit_cpu_context+0x170/0x170 [ 147.187341] ? deref_stack_reg+0xaa/0xe0 [ 147.191391] ? perf_output_copy+0x149/0x1d0 [ 147.195703] ? perf_output_sample+0xcea/0x1700 [ 147.200264] ? __perf_event_header__init_id.isra.0+0x276/0x430 [ 147.206222] ? perf_prepare_sample+0x656/0x1330 [ 147.210874] ? perf_event__output_id_sample+0x70/0x70 [ 147.216043] ? perf_output_sample+0x1700/0x1700 [ 147.220690] ? lock_acquire+0x10f/0x380 [ 147.224644] ? perf_prepare_sample+0x1330/0x1330 [ 147.229398] ? perf_event_output_forward+0x10b/0x220 [ 147.234495] ? perf_prepare_sample+0x1330/0x1330 [ 147.239236] ? check_preemption_disabled+0x35/0x1f0 [ 147.244239] ? __perf_event_overflow+0x116/0x320 [ 147.248977] ? perf_swevent_overflow+0x17b/0x210 [ 147.253713] ? ___perf_sw_event+0x11b/0x4a0 [ 147.258018] ? perf_swevent_event+0x19c/0x270 [ 147.262492] ? ___perf_sw_event+0x2a4/0x4a0 [ 147.266795] ? perf_pending_event+0xd0/0xd0 [ 147.271127] ? __handle_mm_fault+0xd96/0x2640 [ 147.275603] ? lock_downgrade+0x5d0/0x5d0 [ 147.279729] ? __handle_mm_fault+0xcc0/0x2640 [ 147.284210] ? _raw_spin_unlock+0x29/0x40 [ 147.288335] ? __handle_mm_fault+0x6c5/0x2640 [ 147.292811] ? vm_insert_mixed_mkwrite+0x30/0x30 [ 147.297547] ? __brelse+0x43/0x60 [ 147.300988] ? __do_page_fault+0x48e/0xb80 [ 147.305205] ? __perf_sw_event+0x42/0x80 [ 147.309245] ? __perf_sw_event+0x42/0x80 [ 147.313287] ? __do_page_fault+0x785/0xb80 [ 147.317506] ? bad_area_access_error+0x340/0x340 [ 147.322242] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 147.327074] ? page_fault+0x22/0x50 [ 147.330689] ? iov_iter_fault_in_readable+0x29c/0x350 [ 147.335862] ? iov_iter_init+0x1c0/0x1c0 [ 147.339910] ? generic_perform_write+0x158/0x450 [ 147.344653] ? filemap_page_mkwrite+0x2d0/0x2d0 [ 147.349301] ? current_time+0xb0/0xb0 [ 147.353089] ? __generic_file_write_iter+0x32e/0x550 [ 147.358175] ? ext4_file_write_iter+0x551/0xd60 [ 147.362826] ? ext4_llseek+0x7f0/0x7f0 [ 147.366692] ? trace_hardirqs_on+0x10/0x10 [ 147.370916] ? __vfs_write+0x401/0x5a0 [ 147.374786] ? kernel_read+0x110/0x110 [ 147.378664] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 147.384098] ? rcu_read_lock_sched_held+0x10a/0x130 [ 147.389097] ? vfs_write+0x17f/0x4d0 [ 147.392796] ? SyS_write+0xc0/0x1a0 [ 147.396403] ? SyS_read+0x1a0/0x1a0 [ 147.400021] ? SyS_read+0x1a0/0x1a0 [ 147.403631] ? do_syscall_64+0x19b/0x510 [ 147.407677] ? entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 147.413027] [ 147.414635] Allocated by task 2290: [ 147.418266] kasan_kmalloc.part.0+0x4f/0xd0 [ 147.422563] kmem_cache_alloc_trace+0x126/0x310 [ 147.427209] alloc_perf_context+0x44/0xe0 [ 147.431334] find_get_context.isra.0+0x119/0x550 [ 147.436064] SyS_perf_event_open+0x9d3/0x2530 [ 147.440538] do_syscall_64+0x19b/0x510 [ 147.444398] [ 147.446003] Freed by task 2292: [ 147.449261] kasan_slab_free+0xb0/0x190 [ 147.453211] kfree+0xf5/0x310 [ 147.456293] rcu_process_callbacks+0x56f/0xf40 [ 147.460854] __do_softirq+0x234/0x9ca [ 147.464631] [ 147.466238] The buggy address belongs to the object at ffff8881ca2b2280 [ 147.466238] which belongs to the cache kmalloc-512 of size 512 [ 147.478874] The buggy address is located 264 bytes inside of [ 147.478874] 512-byte region [ffff8881ca2b2280, ffff8881ca2b2480) [ 147.490724] The buggy address belongs to the page: [ 147.495632] page:ffffea000728ac80 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 147.505580] flags: 0x4000000000010200(slab|head) [ 147.510319] raw: 4000000000010200 0000000000000000 0000000000000000 00000001000c000c [ 147.518181] raw: ffffea0007288900 0000000500000005 ffff8881da802c00 0000000000000000 [ 147.526035] page dumped because: kasan: bad access detected [ 147.531720] [ 147.533326] Memory state around the buggy address: [ 147.538230] ffff8881ca2b2280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 147.545566] ffff8881ca2b2300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 147.552908] >ffff8881ca2b2380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 147.560243] ^ [ 147.563848] ffff8881ca2b2400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 147.571185] ffff8881ca2b2480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 147.578521] ================================================================== [ 147.585884] Disabling lock debugging due to kernel taint [ 147.591521] Kernel panic - not syncing: panic_on_warn set ... [ 147.591521] [ 147.598879] CPU: 0 PID: 2300 Comm: syz-executor655 Tainted: G B 4.14.123+ #5 [ 147.607182] Call Trace: [ 147.609751] dump_stack+0xb9/0x10e [ 147.613272] panic+0x1d9/0x3c2 [ 147.616456] ? add_taint.cold+0x16/0x16 [ 147.620408] ? retint_kernel+0x2d/0x2d [ 147.624360] ? perf_output_read+0xe58/0xfc0 [ 147.628658] kasan_end_report+0x43/0x49 [ 147.632608] kasan_report.cold+0xca/0x2d5 [ 147.636732] ? perf_output_read+0xe58/0xfc0 [ 147.641034] ? perf_event_exit_cpu_context+0x170/0x170 [ 147.646286] ? deref_stack_reg+0xaa/0xe0 [ 147.650323] ? perf_output_copy+0x149/0x1d0 [ 147.654623] ? perf_output_sample+0xcea/0x1700 [ 147.659181] ? __perf_event_header__init_id.isra.0+0x276/0x430 [ 147.665143] ? perf_prepare_sample+0x656/0x1330 [ 147.669875] ? perf_event__output_id_sample+0x70/0x70 [ 147.675043] ? perf_output_sample+0x1700/0x1700 [ 147.679686] ? lock_acquire+0x10f/0x380 [ 147.683637] ? perf_prepare_sample+0x1330/0x1330 [ 147.688370] ? perf_event_output_forward+0x10b/0x220 [ 147.693449] ? perf_prepare_sample+0x1330/0x1330 [ 147.698201] ? check_preemption_disabled+0x35/0x1f0 [ 147.703195] ? __perf_event_overflow+0x116/0x320 [ 147.707971] ? perf_swevent_overflow+0x17b/0x210 [ 147.712703] ? ___perf_sw_event+0x11b/0x4a0 [ 147.717005] ? perf_swevent_event+0x19c/0x270 [ 147.721475] ? ___perf_sw_event+0x2a4/0x4a0 [ 147.725784] ? perf_pending_event+0xd0/0xd0 [ 147.730088] ? __handle_mm_fault+0xd96/0x2640 [ 147.734564] ? lock_downgrade+0x5d0/0x5d0 [ 147.738692] ? __handle_mm_fault+0xcc0/0x2640 [ 147.743173] ? _raw_spin_unlock+0x29/0x40 [ 147.747316] ? __handle_mm_fault+0x6c5/0x2640 [ 147.751794] ? vm_insert_mixed_mkwrite+0x30/0x30 [ 147.756524] ? __brelse+0x43/0x60 [ 147.759955] ? __do_page_fault+0x48e/0xb80 [ 147.764168] ? __perf_sw_event+0x42/0x80 [ 147.768206] ? __perf_sw_event+0x42/0x80 [ 147.772243] ? __do_page_fault+0x785/0xb80 [ 147.776453] ? bad_area_access_error+0x340/0x340 [ 147.781184] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 147.786007] ? page_fault+0x22/0x50 [ 147.789618] ? iov_iter_fault_in_readable+0x29c/0x350 [ 147.794784] ? iov_iter_init+0x1c0/0x1c0 [ 147.798824] ? generic_perform_write+0x158/0x450 [ 147.803557] ? filemap_page_mkwrite+0x2d0/0x2d0 [ 147.808203] ? current_time+0xb0/0xb0 [ 147.811979] ? __generic_file_write_iter+0x32e/0x550 [ 147.817059] ? ext4_file_write_iter+0x551/0xd60 [ 147.821721] ? ext4_llseek+0x7f0/0x7f0 [ 147.825593] ? trace_hardirqs_on+0x10/0x10 [ 147.829806] ? __vfs_write+0x401/0x5a0 [ 147.833670] ? kernel_read+0x110/0x110 [ 147.837540] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 147.842968] ? rcu_read_lock_sched_held+0x10a/0x130 [ 147.848938] ? vfs_write+0x17f/0x4d0 [ 147.853226] ? SyS_write+0xc0/0x1a0 [ 147.856835] ? SyS_read+0x1a0/0x1a0 [ 147.860438] ? SyS_read+0x1a0/0x1a0 [ 147.864040] ? do_syscall_64+0x19b/0x510 [ 147.868081] ? entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 147.873968] Kernel Offset: 0x9400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 147.884780] Rebooting in 86400 seconds..