[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.243805] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 28.195770] random: sshd: uninitialized urandom read (32 bytes read) [ 28.666687] random: sshd: uninitialized urandom read (32 bytes read) [ 29.191841] random: sshd: uninitialized urandom read (32 bytes read) [ 29.362591] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.63' (ECDSA) to the list of known hosts. [ 34.811146] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 34.909449] [ 34.911083] ============================================ [ 34.916516] WARNING: possible recursive locking detected [ 34.921964] 4.18.0-rc8-next-20180810+ #36 Not tainted [ 34.927256] -------------------------------------------- [ 34.932682] syz-executor388/4460 is trying to acquire lock: [ 34.938464] 00000000177c4370 (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 34.949297] [ 34.949297] but task is already holding lock: [ 34.955384] 00000000bcdd8ee9 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 34.964906] [ 34.964906] other info that might help us debug this: [ 34.971546] Possible unsafe locking scenario: [ 34.971546] [ 34.977582] CPU0 [ 34.980144] ---- [ 34.982705] lock(&(&tlocks[i])->rlock); [ 34.986831] lock(&(&tlocks[i])->rlock); [ 34.990954] [ 34.990954] *** DEADLOCK *** [ 34.990954] [ 34.996989] May be due to missing lock nesting notation [ 34.996989] [ 35.003905] 3 locks held by syz-executor388/4460: [ 35.008722] #0: 000000005b32d9c0 (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 35.015643] #1: 00000000bcdd8ee9 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 35.025596] #2: 00000000d035364c (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 35.036374] [ 35.036374] stack backtrace: [ 35.040855] CPU: 1 PID: 4460 Comm: syz-executor388 Not tainted 4.18.0-rc8-next-20180810+ #36 [ 35.049409] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.058768] Call Trace: [ 35.061362] dump_stack+0x1c9/0x2b4 [ 35.064973] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.070142] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 35.075488] ? vprintk_func+0x81/0x117 [ 35.079352] __lock_acquire.cold.65+0x1fb/0x486 [ 35.084000] ? __lock_acquire+0x7fc/0x5020 [ 35.088213] ? trace_hardirqs_on+0x10/0x10 [ 35.092421] ? trace_hardirqs_on+0x10/0x10 [ 35.096631] ? __lock_acquire+0x7fc/0x5020 [ 35.100893] ? rcu_is_watching+0x8c/0x150 [ 35.105034] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.109710] ? trace_hardirqs_on+0x10/0x10 [ 35.113926] ? __kernel_text_address+0xd/0x40 [ 35.118403] ? unwind_get_return_address+0x61/0xa0 [ 35.123316] ? __save_stack_trace+0x8d/0xf0 [ 35.127622] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 35.132622] ? trace_hardirqs_off+0x10/0x10 [ 35.136925] ? save_stack_trace+0x1a/0x20 [ 35.141052] ? save_trace+0xe0/0x290 [ 35.144749] ? kasan_check_read+0x11/0x20 [ 35.148877] ? __lock_acquire+0x28d9/0x5020 [ 35.153181] lock_acquire+0x1e4/0x540 [ 35.156965] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 35.163623] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 35.170270] ? lock_release+0xa30/0xa30 [ 35.174240] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 35.179419] _raw_spin_lock_bh+0x31/0x40 [ 35.183461] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 35.190130] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 35.196621] ? kasan_check_read+0x11/0x20 [ 35.200758] ? rcu_is_watching+0x8c/0x150 [ 35.204884] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.209616] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 35.216356] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 35.223002] ? parse_nl_config.isra.13+0x550/0x550 [ 35.227911] ? lock_acquire+0x1e4/0x540 [ 35.231879] ? do_csum+0x345/0x410 [ 35.235414] ? lock_release+0xa30/0xa30 [ 35.239365] ? csum_partial+0x21/0x30 [ 35.243143] ? ila_init_saved_csum+0x9b/0x330 [ 35.247615] ? kasan_check_write+0x14/0x20 [ 35.251916] ? do_raw_spin_lock+0xc1/0x200 [ 35.256138] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 35.261329] ? depot_save_stack+0x291/0x470 [ 35.265646] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 35.271772] ? __kmalloc+0x14e/0x760 [ 35.275472] ? genl_rcv_msg+0xc6/0x168 [ 35.279338] ? netlink_rcv_skb+0x172/0x440 [ 35.283549] ? genl_rcv+0x28/0x40 [ 35.286985] ? netlink_unicast+0x5a0/0x760 [ 35.291281] ? netlink_sendmsg+0xa18/0xfc0 [ 35.295515] ? sock_sendmsg+0xd5/0x120 [ 35.299382] ? ___sys_sendmsg+0x7fd/0x930 [ 35.303509] ? __sys_sendmsg+0x11d/0x290 [ 35.307558] ? __x64_sys_sendmsg+0x78/0xb0 [ 35.311769] ? do_syscall_64+0x1b9/0x820 [ 35.315823] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.321186] ? find_held_lock+0x36/0x1c0 [ 35.325226] ? print_usage_bug+0xc0/0xc0 [ 35.329265] ? graph_lock+0x170/0x170 [ 35.333052] ? __lock_is_held+0xb5/0x140 [ 35.337105] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 35.342299] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 35.347309] ? validate_nla+0x2d9/0x7b0 [ 35.351370] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.356888] ? nla_parse+0x32b/0x4e0 [ 35.360584] ? __netlink_ns_capable+0x100/0x130 [ 35.365233] genl_family_rcv_msg+0x8a3/0x1140 [ 35.369749] ? genl_unregister_family+0x8b0/0x8b0 [ 35.374602] ? lock_downgrade+0x8f0/0x8f0 [ 35.378731] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 35.383741] ? kasan_check_read+0x11/0x20 [ 35.387871] ? lock_acquire+0x1e4/0x540 [ 35.391828] ? genl_rcv+0x19/0x40 [ 35.395269] ? radix_tree_lookup+0x21/0x30 [ 35.399496] genl_rcv_msg+0xc6/0x168 [ 35.403189] netlink_rcv_skb+0x172/0x440 [ 35.407239] ? genl_family_rcv_msg+0x1140/0x1140 [ 35.411982] ? netlink_ack+0xbe0/0xbe0 [ 35.415851] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.420499] genl_rcv+0x28/0x40 [ 35.423757] netlink_unicast+0x5a0/0x760 [ 35.427798] ? netlink_attachskb+0x9a0/0x9a0 [ 35.432190] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.437708] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 35.442705] netlink_sendmsg+0xa18/0xfc0 [ 35.446746] ? netlink_unicast+0x760/0x760 [ 35.450991] ? move_addr_to_kernel.part.18+0x100/0x100 [ 35.456338] ? security_socket_sendmsg+0x94/0xc0 [ 35.461608] ? netlink_unicast+0x760/0x760 [ 35.465827] sock_sendmsg+0xd5/0x120 [ 35.469524] ___sys_sendmsg+0x7fd/0x930 [ 35.473482] ? copy_msghdr_from_user+0x580/0x580 [ 35.478226] ? graph_lock+0x170/0x170 [ 35.482013] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.487530] ? __fget_light+0x2f7/0x440 [ 35.491484] ? fget_raw+0x20/0x20 [ 35.494922] ? lock_downgrade+0x8f0/0x8f0 [ 35.499048] ? handle_mm_fault+0x8c4/0xc80 [ 35.503396] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 35.508915] ? sockfd_lookup_light+0xc5/0x160 [ 35.513395] __sys_sendmsg+0x11d/0x290 [ 35.517263] ? __ia32_sys_shutdown+0x80/0x80 [ 35.521661] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.527183] ? __do_page_fault+0x449/0xe50 [ 35.531403] __x64_sys_sendmsg+0x78/0xb0 [ 35.535449] do_syscall_64+0x1b9/0x820 [ 35.539322] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.544233] ? syscall_return_slowpath+0x31d/0x5e0 [ 35.549148] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.554670] ? retint_user+0x18/0x18 [ 35.558367] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.563192] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.568363] RIP: 0033:0x4400f9 [ 35.571539] 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 [ 35.590419] RSP: 002b:00007ffe9ef514f8 EFLAGS: 00000213 ORIG_RAX: 000000000000002e [ 35.598119] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400f9 [ 35.605379] RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003 [