rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10492 ticks this GP) idle=70f4/1/0x4000000000000000 softirq=18427/18534 fqs=3894
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1225984        300            0
rcu: 	cputime:    31455      21023           41   ==> 52480(ms)
rcu: 	(t=10500 jiffies g=11257 q=36411 ncpus=2)
CPU: 1 UID: 0 PID: 6355 Comm: syz.3.58 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:unwind_next_frame+0x1315/0x2390
Code: 83 e0 fe 4c 8d 3c 45 00 00 00 00 49 01 ef 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 07 <4c> 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 8d 47 fc 48 0f 47 d8
RSP: 0018:ffffc900001e0678 EFLAGS: 00000246
RAX: fffffffff1b2e13c RBX: ffffffff8fb6b7ac RCX: dffffc0000000000
RDX: ffffffff8fb6b7ac RSI: ffffffff90325d2e RDI: ffffffff8be332a0
RBP: ffffffff8fb6b7ac R08: 0000000000000001 R09: ffffffff8172c195
R10: dffffc0000000000 R11: fffffbfff1f47007 R12: ffffffff816999c3
R13: ffffffff8fb6b7ac R14: ffffc900001e07a8 R15: ffffffff8fb6b7ac
FS:  00007f0c1c7f66c0(0000) GS:ffff8881a3c1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005640ddd0f950 CR3: 00000000387ce000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __unwind_start+0x5b9/0x760
 arch_stack_walk+0xe4/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kfree+0x18e/0x440
 slab_free_after_rcu_debug+0x60/0x2a0
 rcu_core+0xcab/0x1770
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:ptlock_free+0x0/0x60
Code: 06 12 b4 ff 4d 85 f6 0f 95 c0 5b 41 5e e9 88 81 70 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <66> 0f 1f 00 53 48 89 fb e8 d3 11 b4 ff 48 83 c3 28 48 89 d8 48 c1
RSP: 0018:ffffc90003816bd8 EFLAGS: 00000293
RAX: ffffffff81748239 RBX: ffffea00045aa400 RCX: ffff888109a43980
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00045aa400
RBP: ffffc90003816c90 R08: ffffffff8dfab283 R09: 1ffffffff1bf5650
R10: dffffc0000000000 R11: fffffbfff1bf5651 R12: ffff888109a43ed8
R13: 1ffff92000702d7c R14: ffff888109a43980 R15: dffffc0000000000
 pagetable_dtor_free+0x81/0x3b0
 __mmdrop+0xb5/0x580
 finish_task_switch+0x3ee/0x950
 __schedule+0x17a0/0x4cc0
 preempt_schedule_common+0x83/0xd0
 preempt_schedule+0xae/0xc0
 preempt_schedule_thunk+0x16/0x30
 _raw_spin_unlock_irqrestore+0xfd/0x110
 rcu_preempt_deferred_qs_irqrestore+0x8bd/0xce0
 rcu_read_unlock_special+0x475/0x5e0
 __rcu_read_unlock+0x84/0xe0
 unwind_next_frame+0x19ae/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 __alloc_skb+0x112/0x2d0
 netlink_sendmsg+0x5c6/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0c1e58ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0c1c7f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0c1e7b5fa0 RCX: 00007f0c1e58ebe9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 000000000000000f
RBP: 00007f0c1e611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0c1e7b6038 R14: 00007f0c1e7b5fa0 R15: 00007ffdf8db3e18
 </TASK>
