[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.235470] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.664974] random: sshd: uninitialized urandom read (32 bytes read) [ 25.930609] random: sshd: uninitialized urandom read (32 bytes read) [ 26.497861] random: sshd: uninitialized urandom read (32 bytes read) [ 26.676262] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.35' (ECDSA) to the list of known hosts. [ 32.243218] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 32.346183] [ 32.347833] ============================================ [ 32.353267] WARNING: possible recursive locking detected [ 32.358746] 4.18.0-next-20180816+ #41 Not tainted [ 32.363569] -------------------------------------------- [ 32.369009] syz-executor116/4436 is trying to acquire lock: [ 32.374755] 00000000be1329bb (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.385603] [ 32.385603] but task is already holding lock: [ 32.391617] 0000000045d8e26c (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 32.401217] [ 32.401217] other info that might help us debug this: [ 32.407868] Possible unsafe locking scenario: [ 32.407868] [ 32.413911] CPU0 [ 32.416479] ---- [ 32.419045] lock(&(&tlocks[i])->rlock); [ 32.423179] lock(&(&tlocks[i])->rlock); [ 32.427311] [ 32.427311] *** DEADLOCK *** [ 32.427311] [ 32.433380] May be due to missing lock nesting notation [ 32.433380] [ 32.440296] 3 locks held by syz-executor116/4436: [ 32.445140] #0: 0000000003194020 (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 32.452071] #1: 0000000045d8e26c (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 32.462042] #2: 000000000e93fe95 (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 32.472712] [ 32.472712] stack backtrace: [ 32.477204] CPU: 0 PID: 4436 Comm: syz-executor116 Not tainted 4.18.0-next-20180816+ #41 [ 32.485419] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.494864] Call Trace: [ 32.497447] dump_stack+0x1c9/0x2b4 [ 32.501067] ? dump_stack_print_info.cold.2+0x52/0x52 [ 32.506483] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 32.511855] ? vprintk_func+0x81/0x117 [ 32.515759] __lock_acquire.cold.62+0x1fb/0x486 [ 32.520433] ? __lock_acquire+0x7fc/0x5020 [ 32.524749] ? mark_held_locks+0x160/0x160 [ 32.528977] ? mark_held_locks+0x160/0x160 [ 32.533202] ? __lock_acquire+0x7fc/0x5020 [ 32.537428] ? rcu_is_watching+0x8c/0x150 [ 32.541569] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 32.546230] ? mark_held_locks+0x160/0x160 [ 32.550459] ? __kernel_text_address+0xd/0x40 [ 32.554946] ? unwind_get_return_address+0x61/0xa0 [ 32.559870] ? __save_stack_trace+0x8d/0xf0 [ 32.564183] ? add_lock_to_list.isra.27+0x1ec/0x4b0 [ 32.569193] ? save_trace+0x290/0x290 [ 32.572990] ? save_stack_trace+0x1a/0x20 [ 32.577130] ? save_trace+0xe0/0x290 [ 32.580844] ? kasan_check_read+0x11/0x20 [ 32.585071] ? __lock_acquire+0x28d9/0x5020 [ 32.589433] lock_acquire+0x1e4/0x4f0 [ 32.593229] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.599888] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 32.606544] ? lock_release+0x9f0/0x9f0 [ 32.610512] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 32.615695] _raw_spin_lock_bh+0x31/0x40 [ 32.619748] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.626410] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.632892] ? kasan_check_read+0x11/0x20 [ 32.637031] ? rcu_is_watching+0x8c/0x150 [ 32.641170] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 32.645840] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 32.652593] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 32.659248] ? parse_nl_config.isra.13+0x550/0x550 [ 32.664166] ? lock_acquire+0x1e4/0x4f0 [ 32.668130] ? do_csum+0x345/0x410 [ 32.671660] ? lock_release+0x9f0/0x9f0 [ 32.675626] ? csum_partial+0x21/0x30 [ 32.679423] ? ila_init_saved_csum+0x9b/0x330 [ 32.683967] ? kasan_check_write+0x14/0x20 [ 32.688205] ? do_raw_spin_lock+0xc1/0x200 [ 32.692481] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 32.697664] ? depot_save_stack+0x291/0x470 [ 32.701980] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 32.708114] ? __kmalloc+0x14e/0x720 [ 32.711831] ? genl_rcv_msg+0xc6/0x168 [ 32.715716] ? netlink_rcv_skb+0x172/0x440 [ 32.719940] ? genl_rcv+0x28/0x40 [ 32.723424] ? netlink_unicast+0x5a0/0x760 [ 32.727649] ? netlink_sendmsg+0xa18/0xfc0 [ 32.731872] ? sock_sendmsg+0xd5/0x120 [ 32.735748] ? ___sys_sendmsg+0x7fd/0x930 [ 32.739949] ? __sys_sendmsg+0x11d/0x290 [ 32.743999] ? __x64_sys_sendmsg+0x78/0xb0 [ 32.748225] ? do_syscall_64+0x1b9/0x820 [ 32.752340] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.757734] ? find_held_lock+0x36/0x1c0 [ 32.761795] ? graph_lock+0x170/0x170 [ 32.765603] ? mark_held_locks+0xc9/0x160 [ 32.769740] ? __kmalloc+0x272/0x720 [ 32.773447] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 32.778669] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 32.783676] ? validate_nla+0x2d9/0x7b0 [ 32.787640] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.793209] ? nla_parse+0x32b/0x4e0 [ 32.796916] ? __netlink_ns_capable+0x100/0x130 [ 32.801575] genl_family_rcv_msg+0x8a3/0x1140 [ 32.806109] ? genl_unregister_family+0x8b0/0x8b0 [ 32.810940] ? lock_downgrade+0x8f0/0x8f0 [ 32.815080] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 32.820130] ? kasan_check_read+0x11/0x20 [ 32.824268] ? lock_acquire+0x1e4/0x4f0 [ 32.828231] ? genl_rcv+0x19/0x40 [ 32.831682] ? radix_tree_lookup+0x21/0x30 [ 32.835905] genl_rcv_msg+0xc6/0x168 [ 32.839613] netlink_rcv_skb+0x172/0x440 [ 32.843664] ? genl_family_rcv_msg+0x1140/0x1140 [ 32.848410] ? netlink_ack+0xbe0/0xbe0 [ 32.852286] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 32.856944] genl_rcv+0x28/0x40 [ 32.860212] netlink_unicast+0x5a0/0x760 [ 32.864262] ? netlink_attachskb+0x9a0/0x9a0 [ 32.868663] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.874240] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 32.879246] netlink_sendmsg+0xa18/0xfc0 [ 32.883358] ? netlink_unicast+0x760/0x760 [ 32.887590] ? move_addr_to_kernel.part.18+0x100/0x100 [ 32.892860] ? security_socket_sendmsg+0x94/0xc0 [ 32.897649] ? netlink_unicast+0x760/0x760 [ 32.901874] sock_sendmsg+0xd5/0x120 [ 32.905582] ___sys_sendmsg+0x7fd/0x930 [ 32.909599] ? copy_msghdr_from_user+0x580/0x580 [ 32.914366] ? graph_lock+0x170/0x170 [ 32.918166] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.923693] ? __fget_light+0x2f7/0x440 [ 32.927657] ? fget_raw+0x20/0x20 [ 32.931104] ? __do_page_fault+0x620/0xe50 [ 32.935379] ? lock_downgrade+0x8f0/0x8f0 [ 32.939531] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 32.945061] ? sockfd_lookup_light+0xc5/0x160 [ 32.949547] __sys_sendmsg+0x11d/0x290 [ 32.953423] ? __ia32_sys_shutdown+0x80/0x80 [ 32.957832] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.963364] ? __do_page_fault+0x449/0xe50 [ 32.967594] ? do_syscall_64+0x9a/0x820 [ 32.971558] ? do_syscall_64+0x9a/0x820 [ 32.975532] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 32.980629] __x64_sys_sendmsg+0x78/0xb0 [ 32.984682] do_syscall_64+0x1b9/0x820 [ 32.988563] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 32.993972] ? syscall_return_slowpath+0x5e0/0x5e0 [ 32.998896] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 33.003727] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 33.008737] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 33.014266] ? prepare_exit_to_usermode+0x291/0x3b0 [ 33.019274] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 33.024110] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.029287] RIP: 0033:0x4400f9 [ 33.032471] 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