[....] Starting OpenBSD Secure Shell server: sshd[ 20.917993] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.868214] random: sshd: uninitialized urandom read (32 bytes read) [ 24.216671] sshd (4370) used greatest stack depth: 17096 bytes left [ 24.239279] random: sshd: uninitialized urandom read (32 bytes read) [ 24.804396] random: sshd: uninitialized urandom read (32 bytes read) [ 24.976705] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.29' (ECDSA) to the list of known hosts. [ 30.567477] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 30.662699] netlink: 'syz-executor487': attribute type 4 has an invalid length. [ 30.671306] [ 30.672948] ============================================ [ 30.678527] WARNING: possible recursive locking detected [ 30.684056] 4.18.0-rc8+ #181 Not tainted [ 30.688194] -------------------------------------------- [ 30.693635] syz-executor487/4386 is trying to acquire lock: [ 30.699446] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.710616] [ 30.710616] but task is already holding lock: [ 30.716642] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.726414] [ 30.726414] other info that might help us debug this: [ 30.733074] Possible unsafe locking scenario: [ 30.733074] [ 30.739139] CPU0 [ 30.741713] ---- [ 30.744289] lock(&(&tlocks[i])->rlock); [ 30.748429] lock(&(&tlocks[i])->rlock); [ 30.752631] [ 30.752631] *** DEADLOCK *** [ 30.752631] [ 30.758871] May be due to missing lock nesting notation [ 30.758871] [ 30.765954] 3 locks held by syz-executor487/4386: [ 30.770806] #0: (____ptrval____) (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 30.777738] #1: (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.787739] #2: (____ptrval____) (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.798609] [ 30.798609] stack backtrace: [ 30.803280] CPU: 1 PID: 4386 Comm: syz-executor487 Not tainted 4.18.0-rc8+ #181 [ 30.810727] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.820144] Call Trace: [ 30.822815] dump_stack+0x1c9/0x2b4 [ 30.826730] ? dump_stack_print_info.cold.2+0x52/0x52 [ 30.831920] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.837280] ? vprintk_func+0x81/0xe7 [ 30.841090] __lock_acquire.cold.65+0x1fb/0x486 [ 30.845760] ? __lock_acquire+0x7fc/0x5020 [ 30.850052] ? trace_hardirqs_on+0x10/0x10 [ 30.854307] ? trace_hardirqs_on+0x10/0x10 [ 30.858627] ? __lock_acquire+0x7fc/0x5020 [ 30.862914] ? rcu_is_watching+0x8c/0x150 [ 30.867067] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.871489] ? trace_hardirqs_on+0x10/0x10 [ 30.875719] ? __kernel_text_address+0xd/0x40 [ 30.880271] ? unwind_get_return_address+0x61/0xa0 [ 30.885324] ? __save_stack_trace+0x8d/0xf0 [ 30.889708] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 30.894815] ? trace_hardirqs_off+0x10/0x10 [ 30.899135] ? save_stack_trace+0x1a/0x20 [ 30.903346] ? save_trace+0xe0/0x290 [ 30.907072] ? kasan_check_read+0x11/0x20 [ 30.911238] ? __lock_acquire+0x28d9/0x5020 [ 30.915559] lock_acquire+0x1e4/0x540 [ 30.919426] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.926097] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.932810] ? lock_release+0xa30/0xa30 [ 30.936814] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.942008] _raw_spin_lock_bh+0x31/0x40 [ 30.946090] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.952787] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.959281] ? kasan_check_read+0x11/0x20 [ 30.963496] ? rcu_is_watching+0x8c/0x150 [ 30.967645] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.972065] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 30.978831] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 30.985554] ? parse_nl_config.isra.13+0x550/0x550 [ 30.990486] ? lock_acquire+0x1e4/0x540 [ 30.994615] ? lock_release+0xa30/0xa30 [ 30.998586] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 31.004440] ? ila_init_saved_csum+0x9b/0x330 [ 31.008992] ? kasan_check_write+0x14/0x20 [ 31.013232] ? do_raw_spin_lock+0xc1/0x200 [ 31.017489] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 31.022728] ? wake_up_klogd+0x110/0x110 [ 31.026812] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 31.033020] ? mark_held_locks+0xc9/0x160 [ 31.037176] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 31.041755] ? vprintk_default+0x28/0x30 [ 31.045839] ? vprintk_func+0x81/0xe7 [ 31.049698] ? printk+0xa7/0xcf [ 31.052975] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 31.057729] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 31.062917] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 31.068054] ? validate_nla+0x2d9/0x7b0 [ 31.072187] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.077719] ? nla_parse+0x32b/0x4e0 [ 31.081433] ? __netlink_ns_capable+0x100/0x130 [ 31.086110] genl_family_rcv_msg+0x8a3/0x1140 [ 31.090885] ? genl_unregister_family+0x8b0/0x8b0 [ 31.095727] ? lock_downgrade+0x8f0/0x8f0 [ 31.099932] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 31.105019] ? kasan_check_read+0x11/0x20 [ 31.109179] ? lock_acquire+0x1e4/0x540 [ 31.113149] ? genl_rcv+0x19/0x40 [ 31.116600] ? radix_tree_lookup+0x21/0x30 [ 31.120884] genl_rcv_msg+0xc6/0x168 [ 31.124658] netlink_rcv_skb+0x172/0x440 [ 31.128805] ? genl_family_rcv_msg+0x1140/0x1140 [ 31.133735] ? netlink_ack+0xbe0/0xbe0 [ 31.137677] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 31.142091] genl_rcv+0x28/0x40 [ 31.145373] netlink_unicast+0x5a0/0x760 [ 31.149430] ? netlink_attachskb+0x9a0/0x9a0 [ 31.153839] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.159461] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 31.164475] netlink_sendmsg+0xa18/0xfc0 [ 31.168738] ? netlink_unicast+0x760/0x760 [ 31.173093] ? move_addr_to_kernel.part.18+0x100/0x100 [ 31.178370] ? security_socket_sendmsg+0x94/0xc0 [ 31.183129] ? netlink_unicast+0x760/0x760 [ 31.187581] sock_sendmsg+0xd5/0x120 [ 31.191382] ___sys_sendmsg+0x7fd/0x930 [ 31.195356] ? copy_msghdr_from_user+0x580/0x580 [ 31.200189] ? graph_lock+0x170/0x170 [ 31.204061] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.209608] ? __fget_light+0x2f7/0x440 [ 31.213634] ? fget_raw+0x20/0x20 [ 31.217206] ? lock_downgrade+0x8f0/0x8f0 [ 31.221356] ? handle_mm_fault+0x8c4/0xc80 [ 31.225588] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 31.231128] ? sockfd_lookup_light+0xc5/0x160 [ 31.235818] __sys_sendmsg+0x11d/0x290 [ 31.239822] ? __ia32_sys_shutdown+0x80/0x80 [ 31.244297] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.249842] ? __do_page_fault+0x449/0xe50 [ 31.254087] __x64_sys_sendmsg+0x78/0xb0 [ 31.258153] do_syscall_64+0x1b9/0x820 [ 31.262108] ? syscall_slow_exit_work+0x500/0x500 [ 31.266949] ? syscall_return_slowpath+0x5e0/0x5e0 [ 31.271935] ? syscall_return_slowpath+0x31d/0x5e0 [ 31.276863] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.282608] ? retint_user+0x18/0x18 [ 31.286324] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.291308] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.296551] RIP: 0033:0x440169 [ 31.299731] 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 f