[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.894014] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 28.286547] random: sshd: uninitialized urandom read (32 bytes read) [ 28.673200] random: sshd: uninitialized urandom read (32 bytes read) [ 29.216868] random: sshd: uninitialized urandom read (32 bytes read) [ 29.395331] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.2' (ECDSA) to the list of known hosts. [ 34.903713] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 35.007101] [ 35.008837] ============================= [ 35.013094] WARNING: suspicious RCU usage [ 35.017273] 4.18.0-rc8-next-20180810+ #36 Not tainted [ 35.022513] ----------------------------- [ 35.026738] kernel/bpf/core.c:1582 suspicious rcu_dereference_check() usage! [ 35.033976] [ 35.033976] other info that might help us debug this: [ 35.033976] [ 35.042167] [ 35.042167] rcu_scheduler_active = 2, debug_locks = 1 [ 35.048881] 2 locks held by syz-executor287/4449: [ 35.053759] #0: 00000000d8131c0c (&ctx->mutex){+.+.}, at: perf_event_ctx_lock_nested+0x375/0x600 [ 35.062854] #1: 000000006c916250 (bpf_event_mutex){+.+.}, at: perf_event_query_prog_array+0x1c6/0x380 [ 35.072379] [ 35.072379] stack backtrace: [ 35.076932] CPU: 1 PID: 4449 Comm: syz-executor287 Not tainted 4.18.0-rc8-next-20180810+ #36 [ 35.085505] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.094837] Call Trace: [ 35.097435] dump_stack+0x1c9/0x2b4 [ 35.101063] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.106241] ? vprintk_func+0x81/0x117 [ 35.110140] lockdep_rcu_suspicious+0x14a/0x153 [ 35.114806] bpf_prog_array_copy_core+0x2d9/0x360 [ 35.119635] ? __bpf_prog_run32+0x140/0x140 [ 35.123948] ? __kmalloc+0x5f9/0x760 [ 35.127645] bpf_prog_array_copy_info+0x9a/0x110 [ 35.132398] perf_event_query_prog_array+0x22e/0x380 [ 35.137497] ? perf_event_detach_bpf_prog+0x3d0/0x3d0 [ 35.142684] ? find_held_lock+0x36/0x1c0 [ 35.146737] ? find_held_lock+0x36/0x1c0 [ 35.150787] _perf_ioctl+0x986/0x1600 [ 35.154584] ? __do_sys_perf_event_open+0x2f30/0x2f30 [ 35.159764] ? lock_downgrade+0x8f0/0x8f0 [ 35.163928] ? _raw_spin_unlock_bh+0x30/0x40 [ 35.168325] ? kasan_check_read+0x11/0x20 [ 35.172485] ? rcu_is_watching+0x8c/0x150 [ 35.176614] ? bpf_patch_insn_single+0x2c0/0x2c0 [ 35.181352] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.186036] ? mutex_lock_nested+0x16/0x20 [ 35.190253] ? mutex_lock_nested+0x16/0x20 [ 35.194471] ? perf_event_ctx_lock_nested+0x4df/0x600 [ 35.199656] ? __perf_cgroup_move+0x170/0x170 [ 35.204142] ? bpf_prog_load+0x656/0x1c80 [ 35.208277] perf_ioctl+0x59/0x80 [ 35.211719] ? _perf_ioctl+0x1600/0x1600 [ 35.215791] do_vfs_ioctl+0x1de/0x1720 [ 35.219692] ? check_same_owner+0x340/0x340 [ 35.224012] ? ioctl_preallocate+0x300/0x300 [ 35.228416] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.233938] ? __fget_light+0x2f7/0x440 [ 35.237897] ? fget_raw+0x20/0x20 [ 35.241370] ? __x64_sys_bpf+0x284/0x510 [ 35.245418] ? bpf_prog_get+0x20/0x20 [ 35.249204] ? security_file_ioctl+0x94/0xc0 [ 35.253610] ksys_ioctl+0xa9/0xd0 [ 35.257050] __x64_sys_ioctl+0x73/0xb0 [ 35.260929] do_syscall_64+0x1b9/0x820 [ 35.264802] ? syscall_slow_exit_work+0x500/0x500 [ 35.269631] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.274577] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.279498] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 35.284850] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.289684] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.294855] RIP: 0033:0x440409 [ 35.298034] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 35.316919] RSP: 002b:00007fffc5fc1488 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 [ 35.324611] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440409 [ 35.331879] RDX: 0000000020000180 RSI: 00000000c008240a RDI: 0000000000000003 [ 35.339134] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 35.346390] R10: 00000000004002c8 R11: 0000000000000217 R12: 0000000000401c90 [ 35.353674] R13: 0000000000401d20 R14: 0000000000000000