rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=8de/1/0x4000000000000000 softirq=33780/33781 fqs=33
(detected by 0, t=10502 jiffies, g=53693, q=155)
============================================
WARNING: possible recursive locking detected
5.10.0-rc5-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.4/16718 is trying to acquire lock:
ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: rcu_dump_cpu_stacks+0x9c/0x21e kernel/rcu/tree_stall.h:328
but task is already holding lock:
ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:487 [inline]
ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:646 [inline]
ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3694 [inline]
ffffffff8b33f958 (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 syz-executor.4/16718:
#0: ffff888011753728 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:56 [inline]
#0: ffff888011753728 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x25c/0xb40 arch/x86/mm/fault.c:1313
#1: ffff8880111f0978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
#1: ffff8880111f0978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: wp_page_copy+0x61d/0x23b0 mm/memory.c:2869
#2: ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: print_other_cpu_stall kernel/rcu/tree_stall.h:487 [inline]
#2: ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: check_cpu_stall kernel/rcu/tree_stall.h:646 [inline]
#2: ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: rcu_pending kernel/rcu/tree.c:3694 [inline]
#2: ffffffff8b33f958 (rcu_node_0){-.-.}-{2:2}, at: rcu_sched_clock_irq.cold+0xbc/0xee8 kernel/rcu/tree.c:2567
stack backtrace:
CPU: 0 PID: 16718 Comm: syz-executor.4 Not tainted 5.10.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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:rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline]
RIP: 0010:cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline]
RIP: 0010:csd_lock_wait kernel/smp.c:227 [inline]
RIP: 0010:smp_call_function_single+0x1a9/0x4b0 kernel/smp.c:512
Code: 38 0b 00 48 8b 44 24 10 8b 7c 24 1c 48 8d 74 24 40 48 89 44 24 50 48 8b 44 24 08 48 89 44 24 58 e8 0c fb ff ff 41 89 c5 eb 07 42 38 0b 00 f3 90 44 8b 64 24 48 31 ff 41 83 e4 01 44 89 e6 e8
RSP: 0000:ffffc900019ef9a0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 1ffff9200033df38 RCX: ffffffff8164dc63
RDX: 0000000000000001 RSI: ffff8880152d9a40 RDI: 0000000000000005
RBP: ffffc900019efa80 R08: 0000000000000001 R09: ffffffff8ebb0677
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000008
smp_call_function_many_cond+0x25f/0x9d0 kernel/smp.c:648
on_each_cpu_cond_mask+0x50/0x160 kernel/smp.c:899
__flush_tlb_others arch/x86/include/asm/paravirt.h:74 [inline]
flush_tlb_others arch/x86/mm/tlb.c:823 [inline]
flush_tlb_mm_range+0x2ac/0x3d0 arch/x86/mm/tlb.c:910
flush_tlb_page arch/x86/include/asm/tlbflush.h:235 [inline]
ptep_clear_flush+0x12b/0x160 mm/pgtable-generic.c:97
wp_page_copy+0x8e8/0x23b0 mm/memory.c:2890
do_wp_page+0x3fe/0x1930 mm/memory.c:3134
handle_pte_fault mm/memory.c:4392 [inline]
__handle_mm_fault mm/memory.c:4509 [inline]
handle_mm_fault+0x2f98/0x55d0 mm/memory.c:4607
do_user_addr_fault+0x55b/0xb40 arch/x86/mm/fault.c:1372
handle_page_fault arch/x86/mm/fault.c:1429 [inline]
exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1485
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:583
RIP: 0033:0x412b80
Code: 83 c3 01 e8 82 0d ff ff 39 dd 77 ee 48 8b 44 24 08 89 28 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 0f 1f 84 00 00 00 00 00 <89> 3c b5 00 00 76 00 eb 87 0f 1f 80 00 00 00 00 b8 00 00 00 80 48
RSP: 002b:00007fff83f19c30 EFLAGS: 00010246
RAX: 000000008175d4c7 RBX: 000000006cd0f47b RCX: 0000001b2f320000
RDX: 0000000000000000 RSI: 00000000000014c7 RDI: ffffffff8175d4c7
RBP: 0000000000000000 R08: 000000008175d4c7 R09: 000000008175d4cb
R10: 00007fff83f19d90 R11: 0000000000000246 R12: 000000000118bfa8
R13: 00007f61ab095008 R14: 00007f61ab095000 R15: 0000000000000000