[....] Starting OpenBSD Secure Shell server: sshd[ 23.858770] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 29.483041] random: sshd: uninitialized urandom read (32 bytes read) [ 29.823902] sshd (4450) used greatest stack depth: 16872 bytes left [ 29.843914] random: sshd: uninitialized urandom read (32 bytes read) [ 30.390853] random: sshd: uninitialized urandom read (32 bytes read) [ 30.569071] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.46' (ECDSA) to the list of known hosts. [ 36.101841] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 36.200310] netlink: 'syz-executor650': attribute type 4 has an invalid length. [ 36.208490] [ 36.210108] ============================================ [ 36.215536] WARNING: possible recursive locking detected [ 36.220977] 4.18.0-next-20180815+ #40 Not tainted [ 36.225796] -------------------------------------------- [ 36.231225] syz-executor650/4466 is trying to acquire lock: [ 36.236925] 000000005d458661 (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 36.247858] [ 36.247858] but task is already holding lock: [ 36.253814] 0000000075f79012 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 36.263339] [ 36.263339] other info that might help us debug this: [ 36.270017] Possible unsafe locking scenario: [ 36.270017] [ 36.276058] CPU0 [ 36.278618] ---- [ 36.281178] lock(&(&tlocks[i])->rlock); [ 36.285306] lock(&(&tlocks[i])->rlock); [ 36.289432] [ 36.289432] *** DEADLOCK *** [ 36.289432] [ 36.295481] May be due to missing lock nesting notation [ 36.295481] [ 36.302389] 3 locks held by syz-executor650/4466: [ 36.307204] #0: 0000000017287de4 (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 36.314131] #1: 0000000075f79012 (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 36.324093] #2: 000000008df9fa24 (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 36.334793] [ 36.334793] stack backtrace: [ 36.339280] CPU: 0 PID: 4466 Comm: syz-executor650 Not tainted 4.18.0-next-20180815+ #40 [ 36.347489] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 36.356829] Call Trace: [ 36.359400] dump_stack+0x1c9/0x2b4 [ 36.363010] ? dump_stack_print_info.cold.2+0x52/0x52 [ 36.368224] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 36.373664] ? vprintk_func+0x81/0x117 [ 36.377541] __lock_acquire.cold.62+0x1fb/0x486 [ 36.382198] ? __lock_acquire+0x7fc/0x5020 [ 36.386417] ? mark_held_locks+0x160/0x160 [ 36.390635] ? mark_held_locks+0x160/0x160 [ 36.394893] ? __lock_acquire+0x7fc/0x5020 [ 36.399173] ? rcu_is_watching+0x8c/0x150 [ 36.403312] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.407966] ? mark_held_locks+0x160/0x160 [ 36.412187] ? __kernel_text_address+0xd/0x40 [ 36.416669] ? unwind_get_return_address+0x61/0xa0 [ 36.421581] ? __save_stack_trace+0x8d/0xf0 [ 36.425894] ? add_lock_to_list.isra.27+0x1ec/0x4b0 [ 36.430929] ? save_trace+0x290/0x290 [ 36.434723] ? save_stack_trace+0x1a/0x20 [ 36.438860] ? save_trace+0xe0/0x290 [ 36.442561] ? kasan_check_read+0x11/0x20 [ 36.446692] ? __lock_acquire+0x28d9/0x5020 [ 36.450996] lock_acquire+0x1e4/0x4f0 [ 36.454784] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 36.461433] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 36.468091] ? lock_release+0x9f0/0x9f0 [ 36.472053] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 36.477228] _raw_spin_lock_bh+0x31/0x40 [ 36.481273] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 36.488021] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 36.494499] ? kasan_check_read+0x11/0x20 [ 36.498631] ? rcu_is_watching+0x8c/0x150 [ 36.502763] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.507418] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 36.514154] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 36.520963] ? parse_nl_config.isra.13+0x550/0x550 [ 36.525879] ? lock_acquire+0x1e4/0x4f0 [ 36.529838] ? lock_release+0x9f0/0x9f0 [ 36.533799] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.539318] ? ila_init_saved_csum+0x9b/0x330 [ 36.543794] ? kasan_check_write+0x14/0x20 [ 36.548011] ? do_raw_spin_lock+0xc1/0x200 [ 36.552229] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 36.557401] ? wake_up_klogd+0x110/0x110 [ 36.561447] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 36.567588] ? lockdep_hardirqs_on+0x421/0x5c0 [ 36.572169] ? trace_hardirqs_on+0xbd/0x2c0 [ 36.576482] ? kasan_check_read+0x11/0x20 [ 36.580660] ? ___ratelimit+0x36f/0x655 [ 36.584626] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.589712] ? do_raw_spin_lock+0x200/0x200 [ 36.594018] ? vprintk_default+0x28/0x30 [ 36.598060] ? vprintk_func+0x81/0x117 [ 36.601929] ? printk+0xa7/0xcf [ 36.605199] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 36.609973] ? __kmalloc+0x272/0x720 [ 36.613689] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 36.618888] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 36.623889] ? validate_nla+0x2d9/0x7b0 [ 36.627851] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.633373] ? nla_parse+0x32b/0x4e0 [ 36.637134] ? __netlink_ns_capable+0x100/0x130 [ 36.641798] genl_family_rcv_msg+0x8a3/0x1140 [ 36.646282] ? genl_unregister_family+0x8b0/0x8b0 [ 36.651108] ? lock_downgrade+0x8f0/0x8f0 [ 36.655244] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 36.660248] ? kasan_check_read+0x11/0x20 [ 36.664384] ? lock_acquire+0x1e4/0x4f0 [ 36.668341] ? genl_rcv+0x19/0x40 [ 36.671780] ? radix_tree_lookup+0x21/0x30 [ 36.675998] genl_rcv_msg+0xc6/0x168 [ 36.679700] netlink_rcv_skb+0x172/0x440 [ 36.683751] ? genl_family_rcv_msg+0x1140/0x1140 [ 36.688492] ? netlink_ack+0xbe0/0xbe0 [ 36.692364] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.697016] genl_rcv+0x28/0x40 [ 36.700284] netlink_unicast+0x5a0/0x760 [ 36.704332] ? netlink_attachskb+0x9a0/0x9a0 [ 36.708727] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.714256] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 36.719262] netlink_sendmsg+0xa18/0xfc0 [ 36.723309] ? netlink_unicast+0x760/0x760 [ 36.727527] ? move_addr_to_kernel.part.18+0x100/0x100 [ 36.732801] ? security_socket_sendmsg+0x94/0xc0 [ 36.737553] ? netlink_unicast+0x760/0x760 [ 36.741769] sock_sendmsg+0xd5/0x120 [ 36.745474] ___sys_sendmsg+0x7fd/0x930 [ 36.749435] ? copy_msghdr_from_user+0x580/0x580 [ 36.754180] ? graph_lock+0x170/0x170 [ 36.757969] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.763494] ? __fget_light+0x2f7/0x440 [ 36.767452] ? fget_raw+0x20/0x20 [ 36.771138] ? __do_page_fault+0x620/0xe50 [ 36.775423] ? lock_downgrade+0x8f0/0x8f0 [ 36.779588] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.785124] ? sockfd_lookup_light+0xc5/0x160 [ 36.789604] __sys_sendmsg+0x11d/0x290 [ 36.793478] ? __ia32_sys_shutdown+0x80/0x80 [ 36.797873] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.803437] ? __do_page_fault+0x449/0xe50 [ 36.807676] ? do_syscall_64+0x9a/0x820 [ 36.811640] ? do_syscall_64+0x9a/0x820 [ 36.815632] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.820785] __x64_sys_sendmsg+0x78/0xb0 [ 36.824836] do_syscall_64+0x1b9/0x820 [ 36.828709] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 36.834055] ? syscall_return_slowpath+0x5e0/0x5e0 [ 36.838965] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 36.843786] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 36.848783] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 36.853784] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.859341] ? prepare_exit_to_usermode+0x291/0x3b0 [ 36.864346] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 36.869178] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 36.874348] RIP: 0033:0x440169 [ 36.877525] 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 [ 36.896418] RSP: 002b:00007ffdeca73298 EFLAGS: 00000213 ORIG_RAX: 0000000000000