[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.061453] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.118689] random: sshd: uninitialized urandom read (32 bytes read) [ 23.389476] random: sshd: uninitialized urandom read (32 bytes read) [ 23.914906] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.27' (ECDSA) to the list of known hosts. [ 29.681655] urandom_read: 1 callbacks suppressed [ 29.681661] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 29.781924] [ 29.783636] ============================================ [ 29.789075] WARNING: possible recursive locking detected [ 29.794515] 4.18.0-rc8-next-20180810+ #36 Not tainted [ 29.799852] -------------------------------------------- [ 29.805298] syz-executor102/4402 is trying to acquire lock: [ 29.810998] 00000000bdca5694 (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 29.821837] [ 29.821837] but task is already holding lock: [ 29.827819] 00000000651f91aa (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 29.837350] [ 29.837350] other info that might help us debug this: [ 29.844004] Possible unsafe locking scenario: [ 29.844004] [ 29.850053] CPU0 [ 29.852623] ---- [ 29.855198] lock(&(&tlocks[i])->rlock); [ 29.859336] lock(&(&tlocks[i])->rlock); [ 29.863472] [ 29.863472] *** DEADLOCK *** [ 29.863472] [ 29.869520] May be due to missing lock nesting notation [ 29.869520] [ 29.876438] 3 locks held by syz-executor102/4402: [ 29.881268] #0: 0000000092691c80 (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 29.888209] #1: 00000000651f91aa (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 29.898241] #2: 00000000e207a706 (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 29.909053] [ 29.909053] stack backtrace: [ 29.913545] CPU: 1 PID: 4402 Comm: syz-executor102 Not tainted 4.18.0-rc8-next-20180810+ #36 [ 29.922108] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.931517] Call Trace: [ 29.934105] dump_stack+0x1c9/0x2b4 [ 29.937738] ? dump_stack_print_info.cold.2+0x52/0x52 [ 29.942976] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 29.948388] ? vprintk_func+0x81/0x117 [ 29.952446] __lock_acquire.cold.65+0x1fb/0x486 [ 29.957111] ? __lock_acquire+0x7fc/0x5020 [ 29.961370] ? trace_hardirqs_on+0x10/0x10 [ 29.965609] ? trace_hardirqs_on+0x10/0x10 [ 29.969838] ? __lock_acquire+0x7fc/0x5020 [ 29.974068] ? rcu_is_watching+0x8c/0x150 [ 29.985753] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 29.990561] ? trace_hardirqs_on+0x10/0x10 [ 29.994817] ? __kernel_text_address+0xd/0x40 [ 29.999314] ? unwind_get_return_address+0x61/0xa0 [ 30.004244] ? __save_stack_trace+0x8d/0xf0 [ 30.008620] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 30.013632] ? trace_hardirqs_off+0x10/0x10 [ 30.017949] ? save_stack_trace+0x1a/0x20 [ 30.022093] ? save_trace+0xe0/0x290 [ 30.025823] ? kasan_check_read+0x11/0x20 [ 30.029963] ? __lock_acquire+0x28d9/0x5020 [ 30.034285] lock_acquire+0x1e4/0x540 [ 30.038086] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.044763] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.051448] ? lock_release+0xa30/0xa30 [ 30.055537] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.060727] _raw_spin_lock_bh+0x31/0x40 [ 30.064808] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.071471] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.078223] ? kasan_check_read+0x11/0x20 [ 30.082419] ? rcu_is_watching+0x8c/0x150 [ 30.086649] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 30.091319] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 30.098069] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 30.104731] ? parse_nl_config.isra.13+0x550/0x550 [ 30.109657] ? lock_acquire+0x1e4/0x540 [ 30.113627] ? lock_release+0xa30/0xa30 [ 30.117599] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 30.123138] ? ila_init_saved_csum+0x9b/0x330 [ 30.127640] ? kasan_check_write+0x14/0x20 [ 30.131870] ? do_raw_spin_lock+0xc1/0x200 [ 30.136106] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 30.141307] ? depot_save_stack+0x291/0x470 [ 30.145628] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 30.151851] ? __kmalloc+0x14e/0x760 [ 30.155562] ? genl_rcv_msg+0xc6/0x168 [ 30.159442] ? netlink_rcv_skb+0x172/0x440 [ 30.163758] ? genl_rcv+0x28/0x40 [ 30.167234] ? netlink_unicast+0x5a0/0x760 [ 30.171460] ? netlink_sendmsg+0xa18/0xfc0 [ 30.175691] ? sock_sendmsg+0xd5/0x120 [ 30.179571] ? ___sys_sendmsg+0x7fd/0x930 [ 30.183711] ? __sys_sendmsg+0x11d/0x290 [ 30.187821] ? __x64_sys_sendmsg+0x78/0xb0 [ 30.192051] ? do_syscall_64+0x1b9/0x820 [ 30.196103] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 30.201558] ? find_held_lock+0x36/0x1c0 [ 30.205614] ? print_usage_bug+0xc0/0xc0 [ 30.209669] ? graph_lock+0x170/0x170 [ 30.213462] ? __lock_is_held+0xb5/0x140 [ 30.217577] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.222762] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.227875] ? validate_nla+0x2d9/0x7b0 [ 30.231848] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.237376] ? nla_parse+0x32b/0x4e0 [ 30.241086] ? __netlink_ns_capable+0x100/0x130 [ 30.245748] genl_family_rcv_msg+0x8a3/0x1140 [ 30.250326] ? genl_unregister_family+0x8b0/0x8b0 [ 30.255183] ? lock_downgrade+0x8f0/0x8f0 [ 30.259334] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.264343] ? kasan_check_read+0x11/0x20 [ 30.268487] ? lock_acquire+0x1e4/0x540 [ 30.272452] ? genl_rcv+0x19/0x40 [ 30.275906] ? radix_tree_lookup+0x21/0x30 [ 30.280143] genl_rcv_msg+0xc6/0x168 [ 30.283862] netlink_rcv_skb+0x172/0x440 [ 30.287915] ? genl_family_rcv_msg+0x1140/0x1140 [ 30.292663] ? netlink_ack+0xbe0/0xbe0 [ 30.296543] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 30.301207] genl_rcv+0x28/0x40 [ 30.304478] netlink_unicast+0x5a0/0x760 [ 30.308533] ? netlink_attachskb+0x9a0/0x9a0 [ 30.312938] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.318522] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.323532] netlink_sendmsg+0xa18/0xfc0 [ 30.327588] ? netlink_unicast+0x760/0x760 [ 30.331831] ? move_addr_to_kernel.part.18+0x100/0x100 [ 30.337105] ? security_socket_sendmsg+0x94/0xc0 [ 30.341866] ? netlink_unicast+0x760/0x760 [ 30.346209] sock_sendmsg+0xd5/0x120 [ 30.349917] ___sys_sendmsg+0x7fd/0x930 [ 30.353887] ? copy_msghdr_from_user+0x580/0x580 [ 30.358639] ? graph_lock+0x170/0x170 [ 30.362468] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.368000] ? __fget_light+0x2f7/0x440 [ 30.371968] ? fget_raw+0x20/0x20 [ 30.375416] ? lock_downgrade+0x8f0/0x8f0 [ 30.379558] ? handle_mm_fault+0x8c4/0xc80 [ 30.383857] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 30.389390] ? sockfd_lookup_light+0xc5/0x160 [ 30.393878] __sys_sendmsg+0x11d/0x290 [ 30.397760] ? __ia32_sys_shutdown+0x80/0x80 [ 30.402200] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.407732] ? __do_page_fault+0x449/0xe50 [ 30.411962] __x64_sys_sendmsg+0x78/0xb0 [ 30.416018] do_syscall_64+0x1b9/0x820 [ 30.419901] ? syscall_return_slowpath+0x5e0/0x5e0 [ 30.424844] ? syscall_return_slowpath+0x31d/0x5e0 [ 30.429770] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.435331] ? retint_user+0x18/0x18 [ 30.439039] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 30.443929] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 30.449114] RIP: 0033:0x4400e9 [ 30.452318] 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 [ 30.471217] RSP: 002b:00007ffdce0ac358 EFLAGS: 00000213 ORIG_RAX: 000000000000002e [ 30.478970] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400e9 [ 30.486235] RDX: