rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (1 GPs behind) idle=85a/1/0x4000000000000002 softirq=81173/81174 fqs=5239
(detected by 1, t=10502 jiffies, g=157289, q=210756)
============================================
WARNING: possible recursive locking detected
5.10.0-rc5-syzkaller #0 Not tainted
--------------------------------------------
kworker/u4:5/1042 is trying to acquire lock:
ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: rcu_dump_cpu_stacks+0x9c/0x21e kernel/rcu/tree_stall.h:328
but task is already holding lock:
ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:487 [inline]
ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:646 [inline]
ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3694 [inline]
ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: rcu_sched_clock_irq.cold+0xbc/0xee8 kernel/rcu/tree.c:2567
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(rcu_node_0);
lock(rcu_node_0);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by kworker/u4:5/1042:
#0: ffff888147026138 ((wq_completion)krdsd){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888147026138 ((wq_completion)krdsd){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff888147026138 ((wq_completion)krdsd){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff888147026138 ((wq_completion)krdsd){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff888147026138 ((wq_completion)krdsd){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff888147026138 ((wq_completion)krdsd){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243
#1: ffffc90003d1fda8 ((work_completion)(&cp->cp_down_w)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247
#2: ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:487 [inline]
#2: ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:646 [inline]
#2: ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3694 [inline]
#2: ffffffff8b33f998 (rcu_node_0){-.-.}-{2:2}, at: rcu_sched_clock_irq.cold+0xbc/0xee8 kernel/rcu/tree.c:2567
stack backtrace:
CPU: 1 PID: 1042 Comm: kworker/u4:5 Not tainted 5.10.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_shutdown_worker
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x107/0x163 lib/dump_stack.c:118
print_deadlock_bug kernel/locking/lockdep.c:2761 [inline]
check_deadlock kernel/locking/lockdep.c:2804 [inline]
validate_chain kernel/locking/lockdep.c:3595 [inline]
__lock_acquire.cold+0x15e/0x3b0 kernel/locking/lockdep.c:4832
lock_acquire kernel/locking/lockdep.c:5437 [inline]
lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159
rcu_dump_cpu_stacks+0x9c/0x21e kernel/rcu/tree_stall.h:328
print_other_cpu_stall kernel/rcu/tree_stall.h:504 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:646 [inline]
rcu_pending kernel/rcu/tree.c:3694 [inline]
rcu_sched_clock_irq.cold+0x6c8/0xee8 kernel/rcu/tree.c:2567
update_process_times+0x77/0xd0 kernel/time/timer.c:1709
tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328
__run_hrtimer kernel/time/hrtimer.c:1519 [inline]
__hrtimer_run_queues+0x1ce/0xea0 kernel/time/hrtimer.c:1583
hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1645
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
__sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1097
asm_call_irq_on_stack+0xf/0x20
__run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
sysvec_apic_timer_interrupt+0xbd/0x100 arch/x86/kernel/apic/apic.c:1091
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x25/0x50 kernel/locking/spinlock.c:191
Code: f8 5d c3 66 90 55 48 89 fd 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 2a 3b 6e f8 48 89 ef e8 b2 ef 6e f8 f6 c7 02 75 1a 53 9d 01 00 00 00 e8 b1 5b 63 f8 65 8b 05 ba 05 1a 77 85 c0 74 0a 5b
RSP: 0018:ffffc90003d1f9e8 EFLAGS: 00000206
RAX: 00000000023653e7 RBX: 0000000000000206 RCX: ffffffff8155a947
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffffff8f15f100 R08: 0000000000000001 R09: ffffffff8ebad767
R10: fffffbfff1d75aec R11: 0000000000000000 R12: dffffc0000000000
R13: ffffffff894cb520 R14: 1ffff920007a3f44 R15: ffff888072187728
debug_object_active_state lib/debugobjects.c:940 [inline]
debug_object_active_state+0x260/0x350 lib/debugobjects.c:909
debug_rcu_head_queue kernel/rcu/rcu.h:177 [inline]
__call_rcu kernel/rcu/tree.c:2939 [inline]
call_rcu+0x45/0x700 kernel/rcu/tree.c:3027
destroy_inode+0x129/0x1b0 fs/inode.c:289
iput_final fs/inode.c:1654 [inline]
iput.part.0+0x3fe/0x820 fs/inode.c:1680
iput+0x58/0x70 fs/inode.c:1670
__sock_release net/socket.c:608 [inline]
sock_release+0x15a/0x1b0 net/socket.c:624
rds_tcp_conn_path_shutdown+0x1e5/0x3f0 net/rds/tcp_connect.c:216
rds_conn_shutdown+0x23e/0x930 net/rds/connection.c:386
process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
kthread+0x3b1/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296