[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.358047] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.225036] random: sshd: uninitialized urandom read (32 bytes read) [ 26.412500] random: sshd: uninitialized urandom read (32 bytes read) [ 26.925971] random: sshd: uninitialized urandom read (32 bytes read) [ 27.749351] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.46' (ECDSA) to the list of known hosts. [ 33.283751] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 33.394757] netlink: 'syz-executor622': attribute type 4 has an invalid length. [ 33.402786] [ 33.404406] ============================================ [ 33.409894] WARNING: possible recursive locking detected [ 33.415343] 4.18.0-rc8-next-20180810+ #36 Not tainted [ 33.420503] -------------------------------------------- [ 33.425938] syz-executor622/4389 is trying to acquire lock: [ 33.431628] 00000000d6911ccb (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.442463] [ 33.442463] but task is already holding lock: [ 33.448417] 00000000e9555915 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 33.457944] [ 33.457944] other info that might help us debug this: [ 33.464593] Possible unsafe locking scenario: [ 33.464593] [ 33.470631] CPU0 [ 33.473187] ---- [ 33.475741] lock(&(&tlocks[i])->rlock); [ 33.479868] lock(&(&tlocks[i])->rlock); [ 33.483994] [ 33.483994] *** DEADLOCK *** [ 33.483994] [ 33.490080] May be due to missing lock nesting notation [ 33.490080] [ 33.496999] 3 locks held by syz-executor622/4389: [ 33.501816] #0: 00000000a86ea17f (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 33.508737] #1: 00000000e9555915 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 33.518700] #2: 000000004f1b152f (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 33.529357] [ 33.529357] stack backtrace: [ 33.533835] CPU: 0 PID: 4389 Comm: syz-executor622 Not tainted 4.18.0-rc8-next-20180810+ #36 [ 33.542391] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.551731] Call Trace: [ 33.554313] dump_stack+0x1c9/0x2b4 [ 33.557930] ? dump_stack_print_info.cold.2+0x52/0x52 [ 33.563155] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 33.568514] ? vprintk_func+0x81/0x117 [ 33.572389] __lock_acquire.cold.65+0x1fb/0x486 [ 33.577052] ? __lock_acquire+0x7fc/0x5020 [ 33.581273] ? trace_hardirqs_on+0x10/0x10 [ 33.585493] ? trace_hardirqs_on+0x10/0x10 [ 33.589710] ? __lock_acquire+0x7fc/0x5020 [ 33.593976] ? rcu_is_watching+0x8c/0x150 [ 33.598112] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 33.602763] ? trace_hardirqs_on+0x10/0x10 [ 33.606976] ? __kernel_text_address+0xd/0x40 [ 33.611456] ? unwind_get_return_address+0x61/0xa0 [ 33.616369] ? __save_stack_trace+0x8d/0xf0 [ 33.620679] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 33.625675] ? trace_hardirqs_off+0x10/0x10 [ 33.629984] ? save_stack_trace+0x1a/0x20 [ 33.634124] ? save_trace+0xe0/0x290 [ 33.637820] ? kasan_check_read+0x11/0x20 [ 33.641944] ? __lock_acquire+0x28d9/0x5020 [ 33.646261] lock_acquire+0x1e4/0x540 [ 33.650046] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.656692] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 33.663342] ? lock_release+0xa30/0xa30 [ 33.667351] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 33.672627] _raw_spin_lock_bh+0x31/0x40 [ 33.676672] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.683323] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 33.689799] ? kasan_check_read+0x11/0x20 [ 33.693928] ? rcu_is_watching+0x8c/0x150 [ 33.698054] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 33.702713] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 33.709447] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 33.716175] ? parse_nl_config.isra.13+0x550/0x550 [ 33.721104] ? lock_acquire+0x1e4/0x540 [ 33.725065] ? lock_release+0xa30/0xa30 [ 33.729025] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 33.734545] ? ila_init_saved_csum+0x9b/0x330 [ 33.739025] ? kasan_check_write+0x14/0x20 [ 33.743302] ? do_raw_spin_lock+0xc1/0x200 [ 33.747535] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 33.752709] ? wake_up_klogd+0x110/0x110 [ 33.756756] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 33.762892] ? mark_held_locks+0xc9/0x160 [ 33.767033] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 33.771598] ? vprintk_default+0x28/0x30 [ 33.775638] ? vprintk_func+0x81/0x117 [ 33.779568] ? printk+0xa7/0xcf [ 33.782841] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 33.787583] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 33.792766] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 33.797772] ? validate_nla+0x2d9/0x7b0 [ 33.801938] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 33.807463] ? nla_parse+0x32b/0x4e0 [ 33.811161] ? __netlink_ns_capable+0x100/0x130 [ 33.815811] genl_family_rcv_msg+0x8a3/0x1140 [ 33.820290] ? genl_unregister_family+0x8b0/0x8b0 [ 33.825120] ? lock_downgrade+0x8f0/0x8f0 [ 33.829250] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 33.834250] ? kasan_check_read+0x11/0x20 [ 33.838376] ? lock_acquire+0x1e4/0x540 [ 33.842327] ? genl_rcv+0x19/0x40 [ 33.845772] ? radix_tree_lookup+0x21/0x30 [ 33.850102] genl_rcv_msg+0xc6/0x168 [ 33.854016] netlink_rcv_skb+0x172/0x440 [ 33.858058] ? genl_family_rcv_msg+0x1140/0x1140 [ 33.862793] ? netlink_ack+0xbe0/0xbe0 [ 33.866662] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 33.871319] genl_rcv+0x28/0x40 [ 33.874577] netlink_unicast+0x5a0/0x760 [ 33.878624] ? netlink_attachskb+0x9a0/0x9a0 [ 33.883020] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 33.888547] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 33.893559] netlink_sendmsg+0xa18/0xfc0 [ 33.897610] ? netlink_unicast+0x760/0x760 [ 33.901835] ? move_addr_to_kernel.part.18+0x100/0x100 [ 33.907102] ? security_socket_sendmsg+0x94/0xc0 [ 33.911840] ? netlink_unicast+0x760/0x760 [ 33.916062] sock_sendmsg+0xd5/0x120 [ 33.919761] ___sys_sendmsg+0x7fd/0x930 [ 33.923717] ? copy_msghdr_from_user+0x580/0x580 [ 33.928460] ? graph_lock+0x170/0x170 [ 33.932245] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 33.937817] ? __fget_light+0x2f7/0x440 [ 33.941782] ? fget_raw+0x20/0x20 [ 33.945222] ? lock_downgrade+0x8f0/0x8f0 [ 33.949347] ? handle_mm_fault+0x8c4/0xc80 [ 33.953576] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 33.959099] ? sockfd_lookup_light+0xc5/0x160 [ 33.963587] __sys_sendmsg+0x11d/0x290 [ 33.967461] ? __ia32_sys_shutdown+0x80/0x80 [ 33.971852] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 33.977372] ? __do_page_fault+0x449/0xe50 [ 33.981596] __x64_sys_sendmsg+0x78/0xb0 [ 33.985642] do_syscall_64+0x1b9/0x820 [ 33.989509] ? syscall_return_slowpath+0x5e0/0x5e0 [ 33.994420] ? syscall_return_slowpath+0x31d/0x5e0 [ 33.999333] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.004910] ? retint_user+0x18/0x18 [ 34.008625] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 34.013448] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.018672] RIP: 0033:0x440169 [ 34.021903] 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 [ 34.040865] RSP: 002b:00007ffe66c23798 EFLAGS: 00000213 ORIG_RAX: 0000000000