[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.607085] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.259819] random: sshd: uninitialized urandom read (32 bytes read) [ 25.796397] random: sshd: uninitialized urandom read (32 bytes read) [ 26.307815] random: sshd: uninitialized urandom read (32 bytes read) [ 26.479825] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.13' (ECDSA) to the list of known hosts. [ 32.021984] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 32.118229] [ 32.119886] ============================================ [ 32.125322] WARNING: possible recursive locking detected [ 32.130762] 4.18.0-rc8+ #180 Not tainted [ 32.134811] -------------------------------------------- [ 32.140253] syz-executor384/4444 is trying to acquire lock: [ 32.145951] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.156986] [ 32.156986] but task is already holding lock: [ 32.162953] (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 32.172493] [ 32.172493] other info that might help us debug this: [ 32.179157] Possible unsafe locking scenario: [ 32.179157] [ 32.185205] CPU0 [ 32.187784] ---- [ 32.190353] lock(&(&tlocks[i])->rlock); [ 32.194660] lock(&(&tlocks[i])->rlock); [ 32.198927] [ 32.198927] *** DEADLOCK *** [ 32.198927] [ 32.205129] May be due to missing lock nesting notation [ 32.205129] [ 32.212054] 3 locks held by syz-executor384/4444: [ 32.216886] #0: (____ptrval____) (cb_lock){++++}, at: genl_rcv+0x19/0x40 [ 32.223819] #1: (____ptrval____) (&(&tlocks[i])->rlock){+.+.}, at: ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 32.233882] #2: (____ptrval____) (rcu_read_lock){....}, at: rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 32.244726] [ 32.244726] stack backtrace: [ 32.249337] CPU: 1 PID: 4444 Comm: syz-executor384 Not tainted 4.18.0-rc8+ #180 [ 32.257143] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.267118] Call Trace: [ 32.269941] dump_stack+0x1c9/0x2b4 [ 32.273700] ? dump_stack_print_info.cold.2+0x52/0x52 [ 32.279324] ? ila_xlat_nl_cmd_add_mapping+0x6bb/0x17e0 [ 32.284684] ? vprintk_func+0x81/0xe7 [ 32.288534] __lock_acquire.cold.65+0x1fb/0x486 [ 32.293432] ? __lock_acquire+0x7fc/0x5020 [ 32.297674] ? trace_hardirqs_on+0x10/0x10 [ 32.302047] ? trace_hardirqs_on+0x10/0x10 [ 32.306295] ? __lock_acquire+0x7fc/0x5020 [ 32.310525] ? rcu_is_watching+0x8c/0x150 [ 32.314677] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 32.319081] ? trace_hardirqs_on+0x10/0x10 [ 32.323311] ? __kernel_text_address+0xd/0x40 [ 32.327976] ? unwind_get_return_address+0x61/0xa0 [ 32.332906] ? __save_stack_trace+0x8d/0xf0 [ 32.337225] ? add_lock_to_list.isra.30+0x1ec/0x4b0 [ 32.342336] ? trace_hardirqs_off+0x10/0x10 [ 32.346673] ? save_stack_trace+0x1a/0x20 [ 32.350924] ? save_trace+0xe0/0x290 [ 32.354667] ? kasan_check_read+0x11/0x20 [ 32.358810] ? __lock_acquire+0x28d9/0x5020 [ 32.363129] lock_acquire+0x1e4/0x540 [ 32.366927] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.373588] ? rhashtable_lookup_insert_fast.constprop.26+0x1d7/0x13a0 [ 32.380648] ? lock_release+0xa30/0xa30 [ 32.384647] ? __sanitizer_cov_trace_switch+0x53/0x90 [ 32.389838] _raw_spin_lock_bh+0x31/0x40 [ 32.393998] ? rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.400826] rhashtable_lookup_insert_fast.constprop.26+0x436/0x13a0 [ 32.407453] ? kasan_check_read+0x11/0x20 [ 32.411596] ? rcu_is_watching+0x8c/0x150 [ 32.415765] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 32.420271] ? rhashtable_replace_fast.isra.20.constprop.24+0xb60/0xb60 [ 32.427129] ? rhashtable_lookup_fast.isra.18.constprop.30+0x5a3/0xa60 [ 32.433822] ? parse_nl_config.isra.13+0x550/0x550 [ 32.438752] ? lock_acquire+0x1e4/0x540 [ 32.442848] ? lock_release+0xa30/0xa30 [ 32.446828] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 32.452682] ? ila_init_saved_csum+0x9b/0x330 [ 32.457183] ? kasan_check_write+0x14/0x20 [ 32.461550] ? do_raw_spin_lock+0xc1/0x200 [ 32.465785] ila_xlat_nl_cmd_add_mapping+0xafe/0x17e0 [ 32.470976] ? depot_save_stack+0x291/0x470 [ 32.475297] ? __rhashtable_remove_fast.constprop.25+0xe30/0xe30 [ 32.481437] ? __kmalloc+0x14e/0x760 [ 32.485225] ? genl_rcv_msg+0xc6/0x168 [ 32.489112] ? netlink_rcv_skb+0x172/0x440 [ 32.493467] ? genl_rcv+0x28/0x40 [ 32.496914] ? netlink_unicast+0x5a0/0x760 [ 32.501426] ? netlink_sendmsg+0xa18/0xfc0 [ 32.505765] ? sock_sendmsg+0xd5/0x120 [ 32.509767] ? ___sys_sendmsg+0x7fd/0x930 [ 32.514056] ? __sys_sendmsg+0x11d/0x290 [ 32.518253] ? __x64_sys_sendmsg+0x78/0xb0 [ 32.522894] ? do_syscall_64+0x1b9/0x820 [ 32.526951] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.532452] ? find_held_lock+0x36/0x1c0 [ 32.536689] ? print_usage_bug+0xc0/0xc0 [ 32.540879] ? graph_lock+0x170/0x170 [ 32.544794] ? __lock_is_held+0xb5/0x140 [ 32.548853] ? __lock_is_held+0xb5/0x140 [ 32.553125] ? memset+0x31/0x40 [ 32.556531] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.562064] ? nla_parse+0x32b/0x4e0 [ 32.565931] ? __netlink_ns_capable+0x100/0x130 [ 32.570595] genl_family_rcv_msg+0x8a3/0x1140 [ 32.575274] ? genl_unregister_family+0x8b0/0x8b0 [ 32.580117] ? lock_downgrade+0x8f0/0x8f0 [ 32.584257] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 32.589390] ? kasan_check_read+0x11/0x20 [ 32.593667] ? lock_acquire+0x1e4/0x540 [ 32.597653] ? genl_rcv+0x19/0x40 [ 32.601243] ? radix_tree_lookup+0x21/0x30 [ 32.605472] genl_rcv_msg+0xc6/0x168 [ 32.609352] netlink_rcv_skb+0x172/0x440 [ 32.613543] ? genl_family_rcv_msg+0x1140/0x1140 [ 32.618386] ? netlink_ack+0xbe0/0xbe0 [ 32.622409] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 32.626933] genl_rcv+0x28/0x40 [ 32.630209] netlink_unicast+0x5a0/0x760 [ 32.634434] ? netlink_attachskb+0x9a0/0x9a0 [ 32.638924] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.644764] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 32.649880] netlink_sendmsg+0xa18/0xfc0 [ 32.654057] ? netlink_unicast+0x760/0x760 [ 32.658383] ? move_addr_to_kernel.part.18+0x100/0x100 [ 32.663893] ? security_socket_sendmsg+0x94/0xc0 [ 32.668773] ? netlink_unicast+0x760/0x760 [ 32.673012] sock_sendmsg+0xd5/0x120 [ 32.676738] ___sys_sendmsg+0x7fd/0x930 [ 32.680721] ? copy_msghdr_from_user+0x580/0x580 [ 32.685482] ? graph_lock+0x170/0x170 [ 32.689291] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.694992] ? __fget_light+0x2f7/0x440 [ 32.699516] ? fget_raw+0x20/0x20 [ 32.703302] ? lock_downgrade+0x8f0/0x8f0 [ 32.707466] ? handle_mm_fault+0x8c4/0xc80 [ 32.711731] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 32.717397] ? sockfd_lookup_light+0xc5/0x160 [ 32.722021] __sys_sendmsg+0x11d/0x290 [ 32.725914] ? __ia32_sys_shutdown+0x80/0x80 [ 32.730798] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.736587] ? __do_page_fault+0x449/0xe50 [ 32.740860] __x64_sys_sendmsg+0x78/0xb0 [ 32.744925] do_syscall_64+0x1b9/0x820 [ 32.748928] ? syscall_slow_exit_work+0x500/0x500 [ 32.753777] ? syscall_return_slowpath+0x5e0/0x5e0 [ 32.758713] ? syscall_return_slowpath+0x31d/0x5e0 [ 32.763668] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.769471] ? retint_user+0x18/0x18 [ 32.773187] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.778027] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.783379] RIP: 0033:0x4400c9 [ 32.786560] 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 [ 32.805946] RSP: 002b:00007fff502885b8 EFLAGS: 00000213 ORIG_RAX: 000000000000002e [ 32.813785] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400c9 [