[....] 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[ 23.581497] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.941032] random: sshd: uninitialized urandom read (32 bytes read) [ 27.220401] random: sshd: uninitialized urandom read (32 bytes read) [ 27.758891] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.2' (ECDSA) to the list of known hosts. [ 33.560399] urandom_read: 1 callbacks suppressed [ 33.560405] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 33.663212] [ 33.664858] ============================================ [ 33.670280] WARNING: possible recursive locking detected [ 33.675707] 4.18.0-next-20180814+ #39 Not tainted [ 33.680523] -------------------------------------------- [ 33.685948] syz-executor426/4462 is trying to acquire lock: [ 33.691633] 00000000a9a8d571 (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.702486] [ 33.702486] but task is already holding lock: [ 33.708438] 0000000041a0e935 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 33.717966] [ 33.717966] other info that might help us debug this: [ 33.724616] Possible unsafe locking scenario: [ 33.724616] [ 33.730651] CPU0 [ 33.733231] ---- [ 33.735796] lock(&(&tlocks[i])->rlock); [ 33.739926] lock(&(&tlocks[i])->rlock); [ 33.744052] [ 33.744052] *** DEADLOCK *** [ 33.744052] [ 33.750089] May be due to missing lock nesting notation [ 33.750089] [ 33.756999] 3 locks held by syz-executor426/4462: [ 33.761815] #0: 00000000b2c5ff71 (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 33.768748] #1: 0000000041a0e935 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 33.778721] #2: 0000000092297a7e (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 33.789375] [ 33.789375] stack backtrace: [ 33.793854] CPU: 0 PID: 4462 Comm: syz-executor426 Not tainted 4.18.0-next-20180814+ #39 [ 33.802151] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.811479] Call Trace: [ 33.814066] dump_stack+0x1c9/0x2b4 [ 33.817678] ? dump_stack_print_info.cold.2+0x52/0x52 [ 33.823105] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 33.828451] ? vprintk_func+0x81/0x117 [ 33.832322] __lock_acquire.cold.62+0x1fb/0x486 [ 33.836969] ? __lock_acquire+0x7fc/0x5020 [ 33.841186] ? mark_held_locks+0x160/0x160 [ 33.845402] ? mark_held_locks+0x160/0x160 [ 33.849621] ? __lock_acquire+0x7fc/0x5020 [ 33.853840] ? rcu_is_watching+0x8c/0x150 [ 33.857967] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 33.862640] ? mark_held_locks+0x160/0x160 [ 33.866858] ? __kernel_text_address+0xd/0x40 [ 33.871347] ? unwind_get_return_address+0x61/0xa0 [ 33.876258] ? __save_stack_trace+0x8d/0xf0 [ 33.880562] ? add_lock_to_list.isra.27+0x1ec/0x4b0 [ 33.885562] ? save_trace+0x290/0x290 [ 33.889344] ? save_stack_trace+0x1a/0x20 [ 33.893474] ? save_trace+0xe0/0x290 [ 33.897181] ? kasan_check_read+0x11/0x20 [ 33.901306] ? __lock_acquire+0x28d9/0x5020 [ 33.905628] lock_acquire+0x1e4/0x4f0 [ 33.909410] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.916065] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 33.922712] ? lock_release+0x9f0/0x9f0 [ 33.926720] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 33.931900] _raw_spin_lock_bh+0x31/0x40 [ 33.935950] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.942612] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.949087] ? kasan_check_read+0x11/0x20 [ 33.953218] ? rcu_is_watching+0x8c/0x150 [ 33.957352] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 33.962002] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 33.968737] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 33.975399] ? parse_nl_config.isra.13+0x550/0x550 [ 33.980307] ? lock_acquire+0x1e4/0x4f0 [ 33.984259] ? lock_release+0x9f0/0x9f0 [ 33.988219] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 33.993739] ? ila_init_saved_csum+0x9b/0x330 [ 33.998218] ? kasan_check_write+0x14/0x20 [ 34.002435] ? do_raw_spin_lock+0xc1/0x200 [ 34.006682] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 34.011853] ? depot_save_stack+0x291/0x470 [ 34.016174] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 34.022302] ? __kmalloc+0x14e/0x720 [ 34.025999] ? genl_rcv_msg+0xc6/0x168 [ 34.029867] ? netlink_rcv_skb+0x172/0x440 [ 34.034084] ? genl_rcv+0x28/0x40 [ 34.037521] ? netlink_unicast+0x5a0/0x760 [ 34.041735] ? netlink_sendmsg+0xa18/0xfc0 [ 34.045981] ? sock_sendmsg+0xd5/0x120 [ 34.049848] ? ___sys_sendmsg+0x7fd/0x930 [ 34.053973] ? __sys_sendmsg+0x11d/0x290 [ 34.058013] ? __x64_sys_sendmsg+0x78/0xb0 [ 34.062231] ? do_syscall_64+0x1b9/0x820 [ 34.066276] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.071636] ? find_held_lock+0x36/0x1c0 [ 34.075689] ? graph_lock+0x170/0x170 [ 34.079488] ? mark_held_locks+0xc9/0x160 [ 34.083646] ? __kmalloc+0x272/0x720 [ 34.087354] ? __lock_is_held+0xb5/0x140 [ 34.091400] ? memset+0x31/0x40 [ 34.094664] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.100185] ? nla_parse+0x32b/0x4e0 [ 34.103895] ? __netlink_ns_capable+0x100/0x130 [ 34.108548] genl_family_rcv_msg+0x8a3/0x1140 [ 34.113027] ? genl_unregister_family+0x8b0/0x8b0 [ 34.117850] ? lock_downgrade+0x8f0/0x8f0 [ 34.121996] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 34.126998] ? kasan_check_read+0x11/0x20 [ 34.131149] ? lock_acquire+0x1e4/0x4f0 [ 34.135124] ? genl_rcv+0x19/0x40 [ 34.138558] ? radix_tree_lookup+0x21/0x30 [ 34.142774] genl_rcv_msg+0xc6/0x168 [ 34.146467] netlink_rcv_skb+0x172/0x440 [ 34.150509] ? genl_family_rcv_msg+0x1140/0x1140 [ 34.155244] ? netlink_ack+0xbe0/0xbe0 [ 34.159124] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 34.163775] genl_rcv+0x28/0x40 [ 34.167042] netlink_unicast+0x5a0/0x760 [ 34.171088] ? netlink_attachskb+0x9a0/0x9a0 [ 34.175482] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.181028] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 34.186051] netlink_sendmsg+0xa18/0xfc0 [ 34.190095] ? netlink_unicast+0x760/0x760 [ 34.194317] ? move_addr_to_kernel.part.18+0x100/0x100 [ 34.199578] ? security_socket_sendmsg+0x94/0xc0 [ 34.204337] ? netlink_unicast+0x760/0x760 [ 34.208551] sock_sendmsg+0xd5/0x120 [ 34.212246] ___sys_sendmsg+0x7fd/0x930 [ 34.216203] ? copy_msghdr_from_user+0x580/0x580 [ 34.220955] ? graph_lock+0x170/0x170 [ 34.224754] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.230272] ? __fget_light+0x2f7/0x440 [ 34.234223] ? fget_raw+0x20/0x20 [ 34.237659] ? __do_page_fault+0x620/0xe50 [ 34.241875] ? lock_downgrade+0x8f0/0x8f0 [ 34.246008] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 34.251524] ? sockfd_lookup_light+0xc5/0x160 [ 34.256001] __sys_sendmsg+0x11d/0x290 [ 34.259893] ? __ia32_sys_shutdown+0x80/0x80 [ 34.264281] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.269803] ? __do_page_fault+0x449/0xe50 [ 34.274024] ? do_syscall_64+0x9a/0x820 [ 34.277980] ? do_syscall_64+0x9a/0x820 [ 34.281953] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 34.287039] __x64_sys_sendmsg+0x78/0xb0 [ 34.291092] do_syscall_64+0x1b9/0x820 [ 34.294990] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 34.300348] ? syscall_return_slowpath+0x5e0/0x5e0 [ 34.305255] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 34.310088] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 34.315087] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 34.320097] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.325639] ? prepare_exit_to_usermode+0x291/0x3b0 [ 34.330638] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 34.335462] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.340643] RIP: 0033:0x4400c9 [ 34.343836] 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 [ 34.362730] RSP: 002b:00007ffc2bc19398 E