[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.353143] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 23.400740] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.813308] random: sshd: uninitialized urandom read (32 bytes read) [ 24.325212] random: sshd: uninitialized urandom read (32 bytes read) [ 24.502553] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.4' (ECDSA) to the list of known hosts. [ 30.033244] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 30.131270] netlink: 'syz-executor200': attribute type 8 has an invalid length. [ 30.139418] [ 30.141049] ============================================ [ 30.146474] WARNING: possible recursive locking detected [ 30.151902] 4.18.0-rc8+ #180 Not tainted [ 30.155935] -------------------------------------------- [ 30.161367] syz-executor200/4445 is trying to acquire lock: [ 30.167055] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.177889] [ 30.177889] but task is already holding lock: [ 30.183839] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.193364] [ 30.193364] other info that might help us debug this: [ 30.200007] Possible unsafe locking scenario: [ 30.200007] [ 30.206057] CPU0 [ 30.208618] ---- [ 30.211177] lock(&(&tlocks[i])->rlock); [ 30.215303] lock(&(&tlocks[i])->rlock); [ 30.219431] [ 30.219431] *** DEADLOCK *** [ 30.219431] [ 30.225465] May be due to missing lock nesting notation [ 30.225465] [ 30.232377] 3 locks held by syz-executor200/4445: [ 30.237201] #0: (____ptrval____) (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 30.244118] #1: (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.254074] #2: (____ptrval____) (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.264724] [ 30.264724] stack backtrace: [ 30.269204] CPU: 0 PID: 4445 Comm: syz-executor200 Not tainted 4.18.0-rc8+ #180 [ 30.276625] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.285956] Call Trace: [ 30.288528] dump_stack+0x1c9/0x2b4 [ 30.292136] ? dump_stack_print_info.cold.2+0x52/0x52 [ 30.297326] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.302671] ? vprintk_func+0x81/0xe7 [ 30.306472] __lock_acquire.cold.65+0x1fb/0x486 [ 30.311142] ? __lock_acquire+0x7fc/0x5020 [ 30.315362] ? trace_hardirqs_on+0x10/0x10 [ 30.319593] ? trace_hardirqs_on+0x10/0x10 [ 30.323807] ? __lock_acquire+0x7fc/0x5020 [ 30.328026] ? rcu_is_watching+0x8c/0x150 [ 30.332166] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.336563] ? trace_hardirqs_on+0x10/0x10 [ 30.340787] ? __kernel_text_address+0xd/0x40 [ 30.345283] ? unwind_get_return_address+0x61/0xa0 [ 30.350194] ? __save_stack_trace+0x8d/0xf0 [ 30.354517] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 30.359514] ? trace_hardirqs_off+0x10/0x10 [ 30.363817] ? save_stack_trace+0x1a/0x20 [ 30.367946] ? save_trace+0xe0/0x290 [ 30.371641] ? kasan_check_read+0x11/0x20 [ 30.375771] ? __lock_acquire+0x28d9/0x5020 [ 30.380076] lock_acquire+0x1e4/0x540 [ 30.383874] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.390526] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.397195] ? lock_release+0xa30/0xa30 [ 30.401155] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.406347] _raw_spin_lock_bh+0x31/0x40 [ 30.410404] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.417065] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.423550] ? kasan_check_read+0x11/0x20 [ 30.427680] ? rcu_is_watching+0x8c/0x150 [ 30.431811] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.436209] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 30.442950] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 30.449599] ? parse_nl_config.isra.13+0x550/0x550 [ 30.454510] ? lock_acquire+0x1e4/0x540 [ 30.458489] ? lock_release+0xa30/0xa30 [ 30.462450] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 30.467966] ? ila_init_saved_csum+0x9b/0x330 [ 30.472444] ? kasan_check_write+0x14/0x20 [ 30.476681] ? do_raw_spin_lock+0xc1/0x200 [ 30.480922] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 30.486097] ? wake_up_klogd+0x110/0x110 [ 30.490141] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 30.496269] ? mark_held_locks+0xc9/0x160 [ 30.500402] ? do_raw_spin_trylock+0x1c0/0x1c0 [ 30.504966] ? vprintk_default+0x28/0x30 [ 30.509011] ? vprintk_func+0x81/0xe7 [ 30.512803] ? printk+0xa7/0xcf [ 30.516064] ? kmsg_dump_rewind_nolock+0xe4/0xe4 [ 30.520802] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.525974] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.531084] ? validate_nla+0x2d9/0x7b0 [ 30.535053] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.540579] ? nla_parse+0x32b/0x4e0 [ 30.544281] ? __netlink_ns_capable+0x100/0x130 [ 30.548931] genl_family_rcv_msg+0x8a3/0x1140 [ 30.553420] ? genl_unregister_family+0x8b0/0x8b0 [ 30.558245] ? lock_downgrade+0x8f0/0x8f0 [ 30.562493] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.567491] ? kasan_check_read+0x11/0x20 [ 30.571622] ? lock_acquire+0x1e4/0x540 [ 30.575576] ? genl_rcv+0x19/0x40 [ 30.579024] ? radix_tree_lookup+0x21/0x30 [ 30.583248] genl_rcv_msg+0xc6/0x168 [ 30.586943] netlink_rcv_skb+0x172/0x440 [ 30.590988] ? genl_family_rcv_msg+0x1140/0x1140 [ 30.595730] ? netlink_ack+0xbe0/0xbe0 [ 30.599603] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.603999] genl_rcv+0x28/0x40 [ 30.607273] netlink_unicast+0x5a0/0x760 [ 30.611316] ? netlink_attachskb+0x9a0/0x9a0 [ 30.615709] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.621232] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.626239] netlink_sendmsg+0xa18/0xfc0 [ 30.630320] ? netlink_unicast+0x760/0x760 [ 30.634549] ? move_addr_to_kernel.part.18+0x100/0x100 [ 30.639817] ? security_socket_sendmsg+0x94/0xc0 [ 30.644561] ? netlink_unicast+0x760/0x760 [ 30.648793] sock_sendmsg+0xd5/0x120 [ 30.652502] ___sys_sendmsg+0x7fd/0x930 [ 30.656466] ? copy_msghdr_from_user+0x580/0x580 [ 30.661213] ? graph_lock+0x170/0x170 [ 30.665010] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.670548] ? __fget_light+0x2f7/0x440 [ 30.674511] ? fget_raw+0x20/0x20 [ 30.677957] ? lock_downgrade+0x8f0/0x8f0 [ 30.682100] ? handle_mm_fault+0x8c4/0xc80 [ 30.686325] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 30.691859] ? sockfd_lookup_light+0xc5/0x160 [ 30.696347] __sys_sendmsg+0x11d/0x290 [ 30.700242] ? __ia32_sys_shutdown+0x80/0x80 [ 30.704642] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.710172] ? __do_page_fault+0x449/0xe50 [ 30.714468] __x64_sys_sendmsg+0x78/0xb0 [ 30.718525] do_syscall_64+0x1b9/0x820 [ 30.722411] ? syscall_return_slowpath+0x5e0/0x5e0 [ 30.727331] ? syscall_return_slowpath+0x31d/0x5e0 [ 30.732271] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.737849] ? retint_user+0x18/0x18 [ 30.741570] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 30.746411] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 30.751591] RIP: 0033:0x4400e9 [ 30.754765] 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 [ 30.773883] RSP: 002b:00007ffe37d55918 EFLAGS: 00000213 ORIG_RAX: 000000000000002e [ 30.781588] RAX: fffffffff