[....] 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[ 19.280714] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.140159] random: sshd: uninitialized urandom read (32 bytes read) [ 24.376104] random: sshd: uninitialized urandom read (32 bytes read) [ 24.880560] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.14' (ECDSA) to the list of known hosts. [ 30.558367] urandom_read: 1 callbacks suppressed [ 30.558372] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 30.657397] [ 30.659045] ============================================ [ 30.664465] WARNING: possible recursive locking detected [ 30.669891] 4.18.0-rc8+ #183 Not tainted [ 30.673925] -------------------------------------------- [ 30.679348] syz-executor821/4372 is trying to acquire lock: [ 30.685074] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.695919] [ 30.695919] but task is already holding lock: [ 30.701866] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.711502] [ 30.711502] other info that might help us debug this: [ 30.718143] Possible unsafe locking scenario: [ 30.718143] [ 30.724176] CPU0 [ 30.726732] ---- [ 30.729288] lock(&(&tlocks[i])->rlock); [ 30.733415] lock(&(&tlocks[i])->rlock); [ 30.737593] [ 30.737593] *** DEADLOCK *** [ 30.737593] [ 30.743636] May be due to missing lock nesting notation [ 30.743636] [ 30.750539] 3 locks held by syz-executor821/4372: [ 30.755351] #0: (____ptrval____) (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 30.762268] #1: (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.772240] #2: (____ptrval____) (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.782947] [ 30.782947] stack backtrace: [ 30.787429] CPU: 1 PID: 4372 Comm: syz-executor821 Not tainted 4.18.0-rc8+ #183 [ 30.794852] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.804182] Call Trace: [ 30.806749] dump_stack+0x1c9/0x2b4 [ 30.810360] ? dump_stack_print_info.cold.2+0x52/0x52 [ 30.815530] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.820874] ? vprintk_func+0x81/0xe7 [ 30.824655] __lock_acquire.cold.65+0x1fb/0x486 [ 30.829367] ? __lock_acquire+0x7fc/0x5020 [ 30.833657] ? trace_hardirqs_on+0x10/0x10 [ 30.837894] ? trace_hardirqs_on+0x10/0x10 [ 30.842129] ? __lock_acquire+0x7fc/0x5020 [ 30.846342] ? rcu_is_watching+0x8c/0x150 [ 30.850466] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.854855] ? trace_hardirqs_on+0x10/0x10 [ 30.859071] ? __kernel_text_address+0xd/0x40 [ 30.863544] ? unwind_get_return_address+0x61/0xa0 [ 30.868464] ? __save_stack_trace+0x8d/0xf0 [ 30.872762] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 30.877919] ? trace_hardirqs_off+0x10/0x10 [ 30.882239] ? save_stack_trace+0x1a/0x20 [ 30.886364] ? save_trace+0xe0/0x290 [ 30.890161] ? kasan_check_read+0x11/0x20 [ 30.894303] ? __lock_acquire+0x28d9/0x5020 [ 30.898609] lock_acquire+0x1e4/0x540 [ 30.902404] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.909044] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.915686] ? lock_release+0xa30/0xa30 [ 30.919639] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.924822] _raw_spin_lock_bh+0x31/0x40 [ 30.928869] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.935516] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.941984] ? kasan_check_read+0x11/0x20 [ 30.946110] ? rcu_is_watching+0x8c/0x150 [ 30.950232] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.954615] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 30.961346] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 30.967992] ? parse_nl_config.isra.13+0x550/0x550 [ 30.972910] ? lock_acquire+0x1e4/0x540 [ 30.976859] ? do_csum+0x345/0x410 [ 30.980373] ? lock_release+0xa30/0xa30 [ 30.984350] ? csum_partial+0x21/0x30 [ 30.988124] ? ila_init_saved_csum+0x9b/0x330 [ 30.992593] ? kasan_check_write+0x14/0x20 [ 30.996871] ? do_raw_spin_lock+0xc1/0x200 [ 31.001087] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 31.006280] ? depot_save_stack+0x291/0x470 [ 31.010583] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 31.016701] ? __kmalloc+0x14e/0x760 [ 31.020391] ? genl_rcv_msg+0xc6/0x168 [ 31.024254] ? netlink_rcv_skb+0x172/0x440 [ 31.028469] ? genl_rcv+0x28/0x40 [ 31.031898] ? netlink_unicast+0x5a0/0x760 [ 31.036106] ? netlink_sendmsg+0xa18/0xfc0 [ 31.040332] ? sock_sendmsg+0xd5/0x120 [ 31.044193] ? ___sys_sendmsg+0x7fd/0x930 [ 31.048357] ? __sys_sendmsg+0x11d/0x290 [ 31.052397] ? __x64_sys_sendmsg+0x78/0xb0 [ 31.056608] ? do_syscall_64+0x1b9/0x820 [ 31.060649] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.065994] ? find_held_lock+0x36/0x1c0 [ 31.070048] ? print_usage_bug+0xc0/0xc0 [ 31.074089] ? graph_lock+0x170/0x170 [ 31.077866] ? __lock_is_held+0xb5/0x140 [ 31.081909] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 31.087601] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 31.092604] ? validate_nla+0x2d9/0x7b0 [ 31.096557] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.102068] ? nla_parse+0x32b/0x4e0 [ 31.105762] ? __netlink_ns_capable+0x100/0x130 [ 31.110407] genl_family_rcv_msg+0x8a3/0x1140 [ 31.114880] ? genl_unregister_family+0x8b0/0x8b0 [ 31.119700] ? lock_downgrade+0x8f0/0x8f0 [ 31.123824] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 31.128819] ? kasan_check_read+0x11/0x20 [ 31.132946] ? lock_acquire+0x1e4/0x540 [ 31.136894] ? genl_rcv+0x19/0x40 [ 31.140324] ? radix_tree_lookup+0x21/0x30 [ 31.144535] genl_rcv_msg+0xc6/0x168 [ 31.148225] netlink_rcv_skb+0x172/0x440 [ 31.152263] ? genl_family_rcv_msg+0x1140/0x1140 [ 31.157047] ? netlink_ack+0xbe0/0xbe0 [ 31.160917] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 31.165308] genl_rcv+0x28/0x40 [ 31.168562] netlink_unicast+0x5a0/0x760 [ 31.172600] ? netlink_attachskb+0x9a0/0x9a0 [ 31.176989] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.182512] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 31.187502] netlink_sendmsg+0xa18/0xfc0 [ 31.191538] ? netlink_unicast+0x760/0x760 [ 31.195781] ? move_addr_to_kernel.part.18+0x100/0x100 [ 31.201035] ? security_socket_sendmsg+0x94/0xc0 [ 31.205768] ? netlink_unicast+0x760/0x760 [ 31.209982] sock_sendmsg+0xd5/0x120 [ 31.213683] ___sys_sendmsg+0x7fd/0x930 [ 31.217634] ? copy_msghdr_from_user+0x580/0x580 [ 31.222371] ? graph_lock+0x170/0x170 [ 31.226161] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.231681] ? __fget_light+0x2f7/0x440 [ 31.235635] ? fget_raw+0x20/0x20 [ 31.239072] ? lock_downgrade+0x8f0/0x8f0 [ 31.243198] ? handle_mm_fault+0x8c4/0xc80 [ 31.247414] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 31.252952] ? sockfd_lookup_light+0xc5/0x160 [ 31.257423] __sys_sendmsg+0x11d/0x290 [ 31.261290] ? __ia32_sys_shutdown+0x80/0x80 [ 31.265675] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.271443] ? __do_page_fault+0x449/0xe50 [ 31.275669] __x64_sys_sendmsg+0x78/0xb0 [ 31.279705] do_syscall_64+0x1b9/0x820 [ 31.283595] ? syscall_slow_exit_work+0x500/0x500 [ 31.288416] ? syscall_return_slowpath+0x5e0/0x5e0 [ 31.293325] ? syscall_return_slowpath+0x31d/0x5e0 [ 31.298234] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.303750] ? retint_user+0x18/0x18 [ 31.307439] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.312271] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.317432] RIP: 0033:0x4400f9 [ 31.320591] 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 [ 31.339751] RSP: 002b:00007fff2e3faf88 EFLAGS: 00000213 ORIG_RAX: 000000000000002e [ 31.347436] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400f9 [ 31.354679] RDX: 0000000000000000 RSI: 0000000020000080 RDI: