[....] 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[?25l[?1c7[ ok 8[?25h[?0c.
[   84.667680][   T27] kauditd_printk_skb: 4 callbacks suppressed
[   84.667692][   T27] audit: type=1800 audit(1581065990.244:29): pid=9786 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0
[   84.694605][   T27] audit: type=1800 audit(1581065990.244:30): pid=9786 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0

Debian GNU/Linux 7 syzkaller ttyS0

Warning: Permanently added '10.128.0.68' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   96.328388][ T9942] IPVS: ftp: loaded support on port[0] = 21
[   96.413350][    C1] 
[   96.415697][    C1] ================================
[   96.420792][    C1] WARNING: inconsistent lock state
[   96.425952][    C1] 5.5.0-syzkaller #0 Not tainted
[   96.430926][    C1] --------------------------------
[   96.436058][    C1] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   96.442896][    C1] swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[   96.448985][    C1] ffff8880a44069c8 (&(&local->client_conns_lock)->rlock){+.?.}, at: rxrpc_put_client_conn+0x6ed/0xc90
[   96.459936][    C1] {SOFTIRQ-ON-W} state was registered at:
[   96.465670][    C1]   lock_acquire+0x190/0x410
[   96.470316][    C1]   _raw_spin_lock+0x2f/0x40
[   96.474896][    C1]   rxrpc_connect_call+0x358/0x4e30
[   96.480089][    C1]   rxrpc_new_client_call+0x9c0/0x1ad0
[   96.485529][    C1]   rxrpc_do_sendmsg+0xffa/0x1d5f
[   96.490534][    C1]   rxrpc_sendmsg+0x4d6/0x5f0
[   96.495193][    C1]   sock_sendmsg+0xd7/0x130
[   96.499688][    C1]   ____sys_sendmsg+0x358/0x880
[   96.504516][    C1]   ___sys_sendmsg+0x100/0x170
[   96.509256][    C1]   __sys_sendmmsg+0x1bf/0x4d0
[   96.513997][    C1]   __x64_sys_sendmmsg+0x9d/0x100
[   96.519537][    C1]   do_syscall_64+0xfa/0x790
[   96.524276][    C1]   entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   96.530233][    C1] irq event stamp: 175864
[   96.534559][    C1] hardirqs last  enabled at (175864): [<ffffffff87ecc126>] _raw_spin_unlock_irqrestore+0x66/0xe0
[   96.545131][    C1] hardirqs last disabled at (175863): [<ffffffff87ecc49f>] _raw_spin_lock_irqsave+0x6f/0xcd
[   96.555175][    C1] softirqs last  enabled at (175788): [<ffffffff8147568c>] _local_bh_enable+0x1c/0x30
[   96.564689][    C1] softirqs last disabled at (175789): [<ffffffff8147808b>] irq_exit+0x19b/0x1e0
[   96.573747][    C1] 
[   96.573747][    C1] other info that might help us debug this:
[   96.581881][    C1]  Possible unsafe locking scenario:
[   96.581881][    C1] 
[   96.589428][    C1]        CPU0
[   96.592746][    C1]        ----
[   96.596520][    C1]   lock(&(&local->client_conns_lock)->rlock);
[   96.602760][    C1]   <Interrupt>
[   96.606209][    C1]     lock(&(&local->client_conns_lock)->rlock);
[   96.612619][    C1] 
[   96.612619][    C1]  *** DEADLOCK ***
[   96.612619][    C1] 
[   96.620880][    C1] 1 lock held by swapper/1/0:
[   96.625531][    C1]  #0: ffffffff89bac140 (rcu_callback){....}, at: rcu_core+0x562/0x1390
[   96.633899][    C1] 
[   96.633899][    C1] stack backtrace:
[   96.639861][    C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.5.0-syzkaller #0
[   96.647387][    C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   96.657474][    C1] Call Trace:
[   96.660747][    C1]  <IRQ>
[   96.663588][    C1]  dump_stack+0x197/0x210
[   96.667971][    C1]  print_usage_bug.cold+0x327/0x378
[   96.673192][    C1]  mark_lock+0xbb4/0x1220
[   96.677524][    C1]  ? kfree+0x10a/0x2c0
[   96.681614][    C1]  ? check_usage_backwards+0x330/0x330
[   96.687145][    C1]  ? __nf_hook_entries_free+0x31/0x40
[   96.692515][    C1]  __lock_acquire+0x1e8e/0x4a00
[   96.697362][    C1]  ? find_held_lock+0x35/0x130
[   96.702161][    C1]  ? __kasan_check_read+0x11/0x20
[   96.707284][    C1]  ? mark_lock+0xc2/0x1220
[   96.711736][    C1]  ? mark_held_locks+0xf0/0xf0
[   96.716497][    C1]  ? _raw_spin_unlock_irqrestore+0x66/0xe0
[   96.722308][    C1]  lock_acquire+0x190/0x410
[   96.726887][    C1]  ? rxrpc_put_client_conn+0x6ed/0xc90
[   96.732577][    C1]  _raw_spin_lock+0x2f/0x40
[   96.737083][    C1]  ? rxrpc_put_client_conn+0x6ed/0xc90
[   96.742593][    C1]  rxrpc_put_client_conn+0x6ed/0xc90
[   96.747874][    C1]  ? rxrpc_rcu_destroy_call+0xbd/0x200
[   96.753317][    C1]  rxrpc_rcu_destroy_call+0xbd/0x200
[   96.758603][    C1]  rcu_core+0x5e1/0x1390
[   96.762898][    C1]  ? __rcu_read_unlock+0x700/0x700
[   96.768008][    C1]  ? rcu_read_lock_sched_held+0x9c/0xd0
[   96.773553][    C1]  ? rcu_read_lock_any_held.part.0+0x50/0x50
[   96.779649][    C1]  ? run_rebalance_domains+0x227/0x2d0
[   96.785186][    C1]  rcu_core_si+0x9/0x10
[   96.789322][    C1]  __do_softirq+0x262/0x98c
[   96.793837][    C1]  ? sched_clock_cpu+0x1b/0x1b0
[   96.798861][    C1]  irq_exit+0x19b/0x1e0
[   96.803002][    C1]  smp_apic_timer_interrupt+0x1a3/0x610
[   96.808559][    C1]  apic_timer_interrupt+0xf/0x20
[   96.813487][    C1]  </IRQ>
[   96.816420][    C1] RIP: 0010:native_safe_halt+0xe/0x10
[   96.821812][    C1] Code: 48 70 c7 f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 44 d3 5b 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 34 d3 5b 00 fb f4 <c3> cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 7e 2f 76 f9 e8 19
[   96.841417][    C1] RSP: 0018:ffffc90000d3fd68 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
[   96.850049][    C1] RAX: 1ffffffff1367612 RBX: ffff8880a99fc340 RCX: 0000000000000000
[   96.858115][    C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a99fcbd4
[   96.866082][    C1] RBP: ffffc90000d3fd98 R08: ffff8880a99fc340 R09: 0000000000000000
[   96.874263][    C1] R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
[   96.882278][    C1] R13: ffffffff8aa522c0 R14: 0000000000000000 R15: 0000000000000001
[   96.890271][    C1]  ? default_idle+0x4e/0x360
[   96.894987][    C1]  arch_cpu_idle+0xa/0x10
[   96.899361][    C1]  default_idle_call+0x84/0xb0
[   96.904208][    C1]  do_idle+0x3c8/0x6e0
[   96.908269][    C1]  ? arch_cpu_idle_exit+0x80/0x80
[   96.913716][    C