[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.607429] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.541544] random: sshd: uninitialized urandom read (32 bytes read) [ 23.767482] random: sshd: uninitialized urandom read (32 bytes read) [ 24.296796] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.23' (ECDSA) to the list of known hosts. [ 30.067215] urandom_read: 1 callbacks suppressed [ 30.067221] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 30.163778] [ 30.165421] ============================================ [ 30.170843] WARNING: possible recursive locking detected [ 30.176269] 4.18.0-rc8+ #182 Not tainted [ 30.180301] -------------------------------------------- [ 30.185729] syz-executor096/4371 is trying to acquire lock: [ 30.191415] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.202241] [ 30.202241] but task is already holding lock: [ 30.208190] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.217708] [ 30.217708] other info that might help us debug this: [ 30.224347] Possible unsafe locking scenario: [ 30.224347] [ 30.230378] CPU0 [ 30.232941] ---- [ 30.235546] lock(&(&tlocks[i])->rlock); [ 30.239672] lock(&(&tlocks[i])->rlock); [ 30.243806] [ 30.243806] *** DEADLOCK *** [ 30.243806] [ 30.249840] May be due to missing lock nesting notation [ 30.249840] [ 30.256745] 3 locks held by syz-executor096/4371: [ 30.261562] #0: (____ptrval____) (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 30.268495] #1: (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.278454] #2: (____ptrval____) (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.289114] [ 30.289114] stack backtrace: [ 30.293609] CPU: 1 PID: 4371 Comm: syz-executor096 Not tainted 4.18.0-rc8+ #182 [ 30.301039] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.310957] Call Trace: [ 30.313531] dump_stack+0x1c9/0x2b4 [ 30.317140] ? dump_stack_print_info.cold.2+0x52/0x52 [ 30.322310] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 30.327654] ? vprintk_func+0x81/0xe7 [ 30.331436] __lock_acquire.cold.65+0x1fb/0x486 [ 30.336088] ? __lock_acquire+0x7fc/0x5020 [ 30.340305] ? trace_hardirqs_on+0x10/0x10 [ 30.344615] ? trace_hardirqs_on+0x10/0x10 [ 30.348829] ? __lock_acquire+0x7fc/0x5020 [ 30.353048] ? rcu_is_watching+0x8c/0x150 [ 30.357181] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.361572] ? trace_hardirqs_on+0x10/0x10 [ 30.365787] ? __kernel_text_address+0xd/0x40 [ 30.370264] ? unwind_get_return_address+0x61/0xa0 [ 30.375177] ? __save_stack_trace+0x8d/0xf0 [ 30.379581] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 30.384576] ? trace_hardirqs_off+0x10/0x10 [ 30.388876] ? save_stack_trace+0x1a/0x20 [ 30.393010] ? save_trace+0xe0/0x290 [ 30.396718] ? kasan_check_read+0x11/0x20 [ 30.400846] ? __lock_acquire+0x28d9/0x5020 [ 30.405150] lock_acquire+0x1e4/0x540 [ 30.408933] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.415577] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 30.422226] ? lock_release+0xa30/0xa30 [ 30.426182] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.431406] _raw_spin_lock_bh+0x31/0x40 [ 30.435452] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.442100] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 30.448575] ? kasan_check_read+0x11/0x20 [ 30.452703] ? rcu_is_watching+0x8c/0x150 [ 30.456832] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.461221] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 30.467958] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 30.474605] ? parse_nl_config.isra.13+0x550/0x550 [ 30.479517] ? lock_acquire+0x1e4/0x540 [ 30.483470] ? do_csum+0x345/0x410 [ 30.486992] ? lock_release+0xa30/0xa30 [ 30.490948] ? csum_partial+0x21/0x30 [ 30.494729] ? ila_init_saved_csum+0x9b/0x330 [ 30.499208] ? kasan_check_write+0x14/0x20 [ 30.503424] ? do_raw_spin_lock+0xc1/0x200 [ 30.507639] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 30.512812] ? depot_save_stack+0x291/0x470 [ 30.517115] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 30.523236] ? __kmalloc+0x14e/0x760 [ 30.526927] ? genl_rcv_msg+0xc6/0x168 [ 30.530825] ? netlink_rcv_skb+0x172/0x440 [ 30.535046] ? genl_rcv+0x28/0x40 [ 30.538480] ? netlink_unicast+0x5a0/0x760 [ 30.542692] ? netlink_sendmsg+0xa18/0xfc0 [ 30.546911] ? sock_sendmsg+0xd5/0x120 [ 30.550777] ? ___sys_sendmsg+0x7fd/0x930 [ 30.554908] ? __sys_sendmsg+0x11d/0x290 [ 30.558948] ? __x64_sys_sendmsg+0x78/0xb0 [ 30.563164] ? do_syscall_64+0x1b9/0x820 [ 30.567205] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 30.572552] ? find_held_lock+0x36/0x1c0 [ 30.576595] ? print_usage_bug+0xc0/0xc0 [ 30.580639] ? graph_lock+0x170/0x170 [ 30.584421] ? __lock_is_held+0xb5/0x140 [ 30.588468] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 30.593637] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.598631] ? validate_nla+0x2d9/0x7b0 [ 30.602585] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.608102] ? nla_parse+0x32b/0x4e0 [ 30.611799] ? __netlink_ns_capable+0x100/0x130 [ 30.616451] genl_family_rcv_msg+0x8a3/0x1140 [ 30.620941] ? genl_unregister_family+0x8b0/0x8b0 [ 30.625764] ? lock_downgrade+0x8f0/0x8f0 [ 30.630473] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.635472] ? kasan_check_read+0x11/0x20 [ 30.639601] ? lock_acquire+0x1e4/0x540 [ 30.643555] ? genl_rcv+0x19/0x40 [ 30.646989] ? radix_tree_lookup+0x21/0x30 [ 30.651210] genl_rcv_msg+0xc6/0x168 [ 30.654908] netlink_rcv_skb+0x172/0x440 [ 30.658979] ? genl_family_rcv_msg+0x1140/0x1140 [ 30.663716] ? netlink_ack+0xbe0/0xbe0 [ 30.667580] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 30.671969] genl_rcv+0x28/0x40 [ 30.675230] netlink_unicast+0x5a0/0x760 [ 30.679273] ? netlink_attachskb+0x9a0/0x9a0 [ 30.683661] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.689179] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 30.694176] netlink_sendmsg+0xa18/0xfc0 [ 30.698220] ? netlink_unicast+0x760/0x760 [ 30.702437] ? move_addr_to_kernel.part.18+0x100/0x100 [ 30.707698] ? security_socket_sendmsg+0x94/0xc0 [ 30.712434] ? netlink_unicast+0x760/0x760 [ 30.716651] sock_sendmsg+0xd5/0x120 [ 30.720348] ___sys_sendmsg+0x7fd/0x930 [ 30.724305] ? copy_msghdr_from_user+0x580/0x580 [ 30.729047] ? graph_lock+0x170/0x170 [ 30.732835] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.738351] ? __fget_light+0x2f7/0x440 [ 30.742306] ? fget_raw+0x20/0x20 [ 30.745744] ? lock_downgrade+0x8f0/0x8f0 [ 30.749871] ? handle_mm_fault+0x8c4/0xc80 [ 30.754089] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 30.759607] ? sockfd_lookup_light+0xc5/0x160 [ 30.764082] __sys_sendmsg+0x11d/0x290 [ 30.767953] ? __ia32_sys_shutdown+0x80/0x80 [ 30.772342] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.777860] ? __do_page_fault+0x449/0xe50 [ 30.782079] __x64_sys_sendmsg+0x78/0xb0 [ 30.786124] do_syscall_64+0x1b9/0x820 [ 30.789993] ? syscall_slow_exit_work+0x500/0x500 [ 30.794824] ? syscall_return_slowpath+0x5e0/0x5e0 [ 30.799731] ? syscall_return_slowpath+0x31d/0x5e0 [ 30.804641] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.810158] ? retint_user+0x18/0x18 [ 30.813852] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 30.818675] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 30.823871] RIP: 0033:0x4400f9 [ 30.827057] 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 [ 30.846143] RSP: 002b:00007ffe798ca6e8 EFLAGS: 00000213 ORIG_RAX: 000000000000002e [ 30.853938] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400f9 [ 30.861201] RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0