[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 24.039578] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 28.110796] random: sshd: uninitialized urandom read (32 bytes read) [ 28.452137] random: sshd: uninitialized urandom read (32 bytes read) [ 29.029105] random: sshd: uninitialized urandom read (32 bytes read) [ 29.218592] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.56' (ECDSA) to the list of known hosts. [ 34.703822] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 34.803544] [ 34.805381] ============================================ [ 34.810820] WARNING: possible recursive locking detected [ 34.816260] 4.18.0-next-20180814+ #39 Not tainted [ 34.821089] -------------------------------------------- [ 34.826670] syz-executor375/4513 is trying to acquire lock: [ 34.832370] 0000000023295875 (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 34.843215] [ 34.843215] but task is already holding lock: [ 34.849178] 00000000e63da04f (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 34.858851] [ 34.858851] other info that might help us debug this: [ 34.865597] Possible unsafe locking scenario: [ 34.865597] [ 34.871645] CPU0 [ 34.874218] ---- [ 34.876787] lock(&(&tlocks[i])->rlock); [ 34.880924] lock(&(&tlocks[i])->rlock); [ 34.885090] [ 34.885090] *** DEADLOCK *** [ 34.885090] [ 34.891287] May be due to missing lock nesting notation [ 34.891287] [ 34.898221] 3 locks held by syz-executor375/4513: [ 34.903162] #0: 00000000b0f1f560 (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 34.910229] #1: 00000000e63da04f (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 34.920209] #2: 0000000000e9ae4a (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 34.930883] [ 34.930883] stack backtrace: [ 34.935383] CPU: 1 PID: 4513 Comm: syz-executor375 Not tainted 4.18.0-next-20180814+ #39 [ 34.943746] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.953335] Call Trace: [ 34.955925] dump_stack+0x1c9/0x2b4 [ 34.959582] ? dump_stack_print_info.cold.2+0x52/0x52 [ 34.964779] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 34.970405] ? vprintk_func+0x81/0x117 [ 34.974305] __lock_acquire.cold.62+0x1fb/0x486 [ 34.978993] ? __lock_acquire+0x7fc/0x5020 [ 34.983224] ? mark_held_locks+0x160/0x160 [ 34.987455] ? mark_held_locks+0x160/0x160 [ 34.991683] ? __lock_acquire+0x7fc/0x5020 [ 34.995913] ? rcu_is_watching+0x8c/0x150 [ 35.000067] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.004733] ? mark_held_locks+0x160/0x160 [ 35.008988] ? __kernel_text_address+0xd/0x40 [ 35.013636] ? unwind_get_return_address+0x61/0xa0 [ 35.018565] ? __save_stack_trace+0x8d/0xf0 [ 35.022909] ? add_lock_to_list.isra.27+0x1ec/0x4b0 [ 35.028037] ? save_trace+0x290/0x290 [ 35.031838] ? save_stack_trace+0x1a/0x20 [ 35.036006] ? save_trace+0xe0/0x290 [ 35.039726] ? kasan_check_read+0x11/0x20 [ 35.043870] ? __lock_acquire+0x28d9/0x5020 [ 35.048194] lock_acquire+0x1e4/0x4f0 [ 35.052016] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 35.058943] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 35.065664] ? lock_release+0x9f0/0x9f0 [ 35.069640] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 35.074831] _raw_spin_lock_bh+0x31/0x40 [ 35.078892] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 35.085556] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 35.092207] ? kasan_check_read+0x11/0x20 [ 35.096452] ? rcu_is_watching+0x8c/0x150 [ 35.100710] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.105392] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 35.112148] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 35.119014] ? parse_nl_config.isra.13+0x550/0x550 [ 35.124075] ? lock_acquire+0x1e4/0x4f0 [ 35.128050] ? do_csum+0x345/0x410 [ 35.131622] ? lock_release+0x9f0/0x9f0 [ 35.135816] ? csum_partial+0x21/0x30 [ 35.139614] ? ila_init_saved_csum+0x9b/0x330 [ 35.144258] ? kasan_check_write+0x14/0x20 [ 35.148491] ? do_raw_spin_lock+0xc1/0x200 [ 35.152838] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 35.158034] ? depot_save_stack+0x291/0x470 [ 35.162354] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 35.168589] ? __kmalloc+0x14e/0x720 [ 35.172306] ? genl_rcv_msg+0xc6/0x168 [ 35.176192] ? netlink_rcv_skb+0x172/0x440 [ 35.180426] ? genl_rcv+0x28/0x40 [ 35.183874] ? netlink_unicast+0x5a0/0x760 [ 35.188103] ? netlink_sendmsg+0xa18/0xfc0 [ 35.192332] ? sock_sendmsg+0xd5/0x120 [ 35.196214] ? ___sys_sendmsg+0x7fd/0x930 [ 35.200356] ? __sys_sendmsg+0x11d/0x290 [ 35.204416] ? __x64_sys_sendmsg+0x78/0xb0 [ 35.208650] ? do_syscall_64+0x1b9/0x820 [ 35.212712] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.218076] ? find_held_lock+0x36/0x1c0 [ 35.222136] ? graph_lock+0x170/0x170 [ 35.226050] ? mark_held_locks+0xc9/0x160 [ 35.230199] ? __kmalloc+0x272/0x720 [ 35.233913] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 35.239101] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 35.244110] ? validate_nla+0x2d9/0x7b0 [ 35.248082] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.253698] ? nla_parse+0x32b/0x4e0 [ 35.257413] ? __netlink_ns_capable+0x100/0x130 [ 35.262220] genl_family_rcv_msg+0x8a3/0x1140 [ 35.266718] ? genl_unregister_family+0x8b0/0x8b0 [ 35.271557] ? lock_downgrade+0x8f0/0x8f0 [ 35.275703] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 35.280885] ? kasan_check_read+0x11/0x20 [ 35.285041] ? lock_acquire+0x1e4/0x4f0 [ 35.289014] ? genl_rcv+0x19/0x40 [ 35.292620] ? radix_tree_lookup+0x21/0x30 [ 35.297003] genl_rcv_msg+0xc6/0x168 [ 35.300849] netlink_rcv_skb+0x172/0x440 [ 35.304908] ? genl_family_rcv_msg+0x1140/0x1140 [ 35.309775] ? netlink_ack+0xbe0/0xbe0 [ 35.313664] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.318329] genl_rcv+0x28/0x40 [ 35.321787] netlink_unicast+0x5a0/0x760 [ 35.325847] ? netlink_attachskb+0x9a0/0x9a0 [ 35.330253] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.335798] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 35.340900] netlink_sendmsg+0xa18/0xfc0 [ 35.345100] ? netlink_unicast+0x760/0x760 [ 35.349487] ? move_addr_to_kernel.part.18+0x100/0x100 [ 35.354763] ? security_socket_sendmsg+0x94/0xc0 [ 35.360009] ? netlink_unicast+0x760/0x760 [ 35.364242] sock_sendmsg+0xd5/0x120 [ 35.367972] ___sys_sendmsg+0x7fd/0x930 [ 35.371970] ? copy_msghdr_from_user+0x580/0x580 [ 35.376727] ? graph_lock+0x170/0x170 [ 35.380644] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.386181] ? __fget_light+0x2f7/0x440 [ 35.390157] ? fget_raw+0x20/0x20 [ 35.393612] ? __do_page_fault+0x620/0xe50 [ 35.397843] ? lock_downgrade+0x8f0/0x8f0 [ 35.402369] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 35.408061] ? sockfd_lookup_light+0xc5/0x160 [ 35.412684] __sys_sendmsg+0x11d/0x290 [ 35.416570] ? __ia32_sys_shutdown+0x80/0x80 [ 35.420997] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.426655] ? __do_page_fault+0x449/0xe50 [ 35.430891] ? do_syscall_64+0x9a/0x820 [ 35.435019] ? do_syscall_64+0x9a/0x820 [ 35.439011] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 35.444113] __x64_sys_sendmsg+0x78/0xb0 [ 35.448172] do_syscall_64+0x1b9/0x820 [ 35.452196] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 35.457888] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.462816] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.469012] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 35.474030] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.479561] ? prepare_exit_to_usermode+0x291/0x3b0 [ 35.484572] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.489410] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.494767] RIP: 0033:0x4400f9 [ 35.498257] 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 [ 35.517562] RSP: 002b:00007ffcce4b2198 EFLAGS: 00000213 ORIG_RAX: 000000000000002e [ 35.525266] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400f9 [ 35.532790] RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003 [ 35.540069] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 35.547335] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401980 [ 35.554882] R13: 00