[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [ 82.998530][ T9728] sshd (9728) used greatest stack depth: 22696 bytes left [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 83.316354][ T27] kauditd_printk_skb: 2 callbacks suppressed [ 83.316366][ T27] audit: type=1800 audit(1581156736.917:29): pid=9661 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 [ 83.343812][ T27] audit: type=1800 audit(1581156736.917:30): pid=9661 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 '10.128.0.24' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 98.813021][ T9814] IPVS: ftp: loaded support on port[0] = 21 [ 98.871927][ C1] [ 98.874440][ C1] ================================ [ 98.879579][ C1] WARNING: inconsistent lock state [ 98.884673][ C1] 5.5.0-syzkaller #0 Not tainted [ 98.889690][ C1] -------------------------------- [ 98.894951][ C1] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 98.901812][ C1] swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes: [ 98.907877][ C1] ffff8880a03119c8 (&(&local->client_conns_lock)->rlock){+.?.}, at: rxrpc_put_client_conn+0x6ed/0xc90 [ 98.919083][ C1] {SOFTIRQ-ON-W} state was registered at: [ 98.925459][ C1] lock_acquire+0x190/0x410 [ 98.930306][ C1] _raw_spin_lock+0x2f/0x40 [ 98.934892][ C1] rxrpc_connect_call+0x358/0x4e30 [ 98.940083][ C1] rxrpc_new_client_call+0x9c0/0x1ad0 [ 98.945653][ C1] rxrpc_do_sendmsg+0xffa/0x1d5f [ 98.950778][ C1] rxrpc_sendmsg+0x4d6/0x5f0 [ 98.955452][ C1] sock_sendmsg+0xd7/0x130 [ 98.960028][ C1] ____sys_sendmsg+0x358/0x880 [ 98.964960][ C1] ___sys_sendmsg+0x100/0x170 [ 98.970091][ C1] __sys_sendmmsg+0x1bf/0x4d0 [ 98.974858][ C1] __x64_sys_sendmmsg+0x9d/0x100 [ 98.979920][ C1] do_syscall_64+0xfa/0x790 [ 98.984517][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 98.990479][ C1] irq event stamp: 158354 [ 98.994845][ C1] hardirqs last enabled at (158354): [] _raw_spin_unlock_irqrestore+0x66/0xe0 [ 99.005531][ C1] hardirqs last disabled at (158353): [] _raw_spin_lock_irqsave+0x6f/0xcd [ 99.015864][ C1] softirqs last enabled at (158278): [] _local_bh_enable+0x1c/0x30 [ 99.025400][ C1] softirqs last disabled at (158279): [] irq_exit+0x19b/0x1e0 [ 99.034397][ C1] [ 99.034397][ C1] other info that might help us debug this: [ 99.042546][ C1] Possible unsafe locking scenario: [ 99.042546][ C1] [ 99.050020][ C1] CPU0 [ 99.053283][ C1] ---- [ 99.056552][ C1] lock(&(&local->client_conns_lock)->rlock); [ 99.063169][ C1] [ 99.066793][ C1] lock(&(&local->client_conns_lock)->rlock); [ 99.073109][ C1] [ 99.073109][ C1] *** DEADLOCK *** [ 99.073109][ C1] [ 99.082343][ C1] 1 lock held by swapper/1/0: [ 99.087006][ C1] #0: ffffffff89bac140 (rcu_callback){....}, at: rcu_core+0x562/0x1390 [ 99.095331][ C1] [ 99.095331][ C1] stack backtrace: [ 99.101306][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.5.0-syzkaller #0 [ 99.108869][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 99.118927][ C1] Call Trace: [ 99.122204][ C1] [ 99.125052][ C1] dump_stack+0x197/0x210 [ 99.129376][ C1] print_usage_bug.cold+0x327/0x378 [ 99.134567][ C1] mark_lock+0xbb4/0x1220 [ 99.138883][ C1] ? kfree+0x10a/0x2c0 [ 99.142941][ C1] ? check_usage_backwards+0x330/0x330 [ 99.148388][ C1] ? __nf_hook_entries_free+0x31/0x40 [ 99.153745][ C1] __lock_acquire+0x1e8e/0x4a00 [ 99.158821][ C1] ? find_held_lock+0x35/0x130 [ 99.163583][ C1] ? __kasan_check_read+0x11/0x20 [ 99.168592][ C1] ? mark_lock+0xc2/0x1220 [ 99.173097][ C1] ? mark_held_locks+0xf0/0xf0 [ 99.177853][ C1] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 99.183692][ C1] lock_acquire+0x190/0x410 [ 99.188244][ C1] ? rxrpc_put_client_conn+0x6ed/0xc90 [ 99.194070][ C1] _raw_spin_lock+0x2f/0x40 [ 99.198610][ C1] ? rxrpc_put_client_conn+0x6ed/0xc90 [ 99.204057][ C1] rxrpc_put_client_conn+0x6ed/0xc90 [ 99.209408][ C1] ? rxrpc_rcu_destroy_call+0xbd/0x200 [ 99.214875][ C1] rxrpc_rcu_destroy_call+0xbd/0x200 [ 99.220358][ C1] rcu_core+0x5e1/0x1390 [ 99.224608][ C1] ? __rcu_read_unlock+0x700/0x700 [ 99.229712][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 99.235339][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 99.241316][ C1] ? run_rebalance_domains+0x227/0x2d0 [ 99.246904][ C1] rcu_core_si+0x9/0x10 [ 99.251044][ C1] __do_softirq+0x262/0x98c [ 99.255639][ C1] ? sched_clock_cpu+0x1b/0x1b0 [ 99.260628][ C1] irq_exit+0x19b/0x1e0 [ 99.264835][ C1] smp_apic_timer_interrupt+0x1a3/0x610 [ 99.270523][ C1] apic_timer_interrupt+0xf/0x20 [ 99.275447][ C1] [ 99.278383][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 99.283863][ 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 cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 7e 2f 76 f9 e8 19 [ 99.303731][ C1] RSP: 0018:ffffc90000d3fd68 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 [ 99.312333][ C1] RAX: 1ffffffff1367612 RBX: ffff8880a99fc340 RCX: 0000000000000000 [ 99.320481][ C1] RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a99fcbd4 [ 99.328572][ C1] RBP: ffffc90000d3fd98 R08: ffff8880a99fc340 R09: 0000000000000000 [ 99.336538][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 [ 99.344539][ C1] R13: ffffffff8aa52400 R14: 0000000000000000 R15: 0000000000000001 [ 99.352607][ C1] ? default_idle+0x4e/0x360 [ 99.357195][ C1] arch_cpu_idle+0xa/0x10 [ 99.361510][ C1] default_idle_call+0x84/0xb0 [ 99.366495][ C1] do_idle+0x3c8/0x6e0 [ 99.370589][ C1] ? arch_cpu_idle_exit