rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (8349 ticks this GP) idle=4164/1/0x4000000000000000 softirq=42998/43005 fqs=5248
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1286697         22            0
rcu: 	cputime:    30789      21710           78   ==> 52510(ms)
rcu: 	(t=10502 jiffies g=32709 q=3782 ncpus=2)
CPU: 1 UID: 0 PID: 8795 Comm: syz.9.717 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:rcu_read_unlock_special+0x87/0x4b0
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 92 be f9 10 41 f7 c6 00 00 f0 00 74 49 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001e0620 EFLAGS: 00000206
RAX: 40b77f3df3027000 RBX: 1ffff9200003c0c8 RCX: 40b77f3df3027000
RDX: 0000000000000002 RSI: ffffffff8d9baef1 RDI: ffffffff8be34480
RBP: ffffc900001e06f8 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffffffff8e13f401
R13: dffffc0000000000 R14: 0000000000000246 R15: ffff8880208a0000
FS:  00007f1d8ea7b6c0(0000) GS:ffff8881a3c11000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dbd8158448 CR3: 000000010e51e000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __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_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 slab_free_after_rcu_debug+0x129/0x2a0
 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:finish_task_switch+0x26b/0x950
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 9f 70 ec 09 e8 ea 41 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 18 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90004faf338 EFLAGS: 00000282
RAX: 40b77f3df3027000 RBX: 0000000000000000 RCX: 40b77f3df3027000
RDX: 0000000000000006 RSI: ffffffff8d9baef1 RDI: ffffffff8be34480
RBP: ffffc90004faf390 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff8880208a0000
R13: dffffc0000000000 R14: ffff88810959b980 R15: ffff88813663ab58
 __schedule+0x17a0/0x4cc0
 preempt_schedule_irq+0xb5/0x150
 irqentry_exit+0x6f/0x90
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:rep_movs_alternative+0x57/0x90
Code: 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 73 e8 eb c5 eb 05 c3 cc cc cc cc 48 8b 06 48 89 07 <48> 8d 47 08 48 83 e0 f8 48 29 f8 48 01 c7 48 01 c6 48 29 c1 48 89
RSP: 0018:ffffc90004faf738 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffff88802d2a0000 RCX: 0000000000008000
RDX: 0000000000000001 RSI: 0000200000170140 RDI: ffff88802d2a0000
RBP: ffffc90004faf8b0 R08: ffff88802d2a7fff R09: 1ffff11005a54fff
R10: dffffc0000000000 R11: ffffed1005a55000 R12: 1ffff920009f5f77
R13: 0000200000170140 R14: ffffc90004fafbc8 R15: 0000000000008000
 _copy_from_iter+0x24f/0x1790
 kcm_sendmsg+0xf00/0x2ad0
 __sock_sendmsg+0x21c/0x270
 sock_write_iter+0x258/0x330
 vfs_write+0x5c9/0xb30
 ksys_write+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1d8db8ec29
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:00007f1d8ea7b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1d8ddd5fa0 RCX: 00007f1d8db8ec29
RDX: 00000000fffffdef RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007f1d8dc11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1d8ddd6038 R14: 00007f1d8ddd5fa0 R15: 00007fffe9d6d5e8
 </TASK>
sched: DL replenish lagged too much
