rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=af74/1/0x4000000000000000 softirq=15364/15364 fqs=0
rcu: 	(detected by 0, t=10506 jiffies, g=7409, q=464 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6044 Comm: syz.1.39 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:hrtimer_try_to_cancel+0x7d/0x420
Code: 1b 12 00 48 8b 5c 24 08 48 8b 44 24 10 42 80 3c 30 00 74 08 48 89 df e8 81 c2 75 00 4c 8b 3b 49 8d 5f 10 49 89 dc 49 c1 ec 03 <43> 0f b6 04 34 84 c0 0f 85 bf 00 00 00 8b 2b 89 ee 83 e6 01 31 ff
RSP: 0018:ffffc900001e04e8 EFLAGS: 00000802
RAX: 1ffff110244aa28b RBX: ffff888136627b10 RCX: 1ffff110244aa28c
RDX: 0000000000010100 RSI: 0000000000000004 RDI: ffff888122551428
RBP: 00000000ffffffff R08: ffff888136627a83 R09: 1ffff11026cc4f50
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: 1ffff11026cc4f62
R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff888136627b00
FS:  00007f7d124e16c0(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001205b6000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 hrtimer_cancel+0x3b/0x50
 cpu_clock_event_stop+0xd9/0x130
 __perf_event_overflow+0x580/0xe40
 perf_swevent_hrtimer+0x3c5/0x550
 __hrtimer_run_queues+0x4e0/0xc60
 hrtimer_interrupt+0x45b/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0x52/0xc0
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 1a 71 20 f6 48 89 df e8 72 08 21 f6 e8 0d 5b 4a f6 fb bf 01 00 00 00 <e8> 42 00 13 f6 65 8b 05 cb c0 23 07 85 c0 74 07 5b c3 cc cc cc cc
RSP: 0018:ffffc900001e0c90 EFLAGS: 00000286
RAX: 3fac7d691007fe00 RBX: ffff888136625900 RCX: 3fac7d691007fe00
RDX: 0000000000000002 RSI: ffffffff8d9ba4c8 RDI: 0000000000000001
RBP: ffffc900001e0e10 R08: ffffffff8fa3ab37 R09: 1ffffffff1f47566
R10: dffffc0000000000 R11: fffffbfff1f47567 R12: dffffc0000000000
R13: ffff888136625948 R14: 0000000000000000 R15: 0000000000000000
 __run_timer_base+0x1ad/0x860
 run_timer_softirq+0xb7/0x180
 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:unwind_next_frame+0x214/0x2390
Code: ef 08 8b 15 1e 5f 4b 0c 8d 42 ff 44 39 f8 0f 86 65 18 00 00 44 89 f8 4c 8d 2c 85 9c 5a e0 90 4c 89 e8 48 c1 e8 03 0f b6 04 28 <84> c0 48 89 eb 0f 85 1c 1c 00 00 45 8b 6d 00 44 89 f8 ff c0 48 8d
RSP: 0018:ffffc900043f77d8 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 3fac7d691007fe00
RDX: 00000000000a7e45 RSI: ffffffff8be33e60 RDI: ffffffff8be33e20
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172d195
R10: ffffc900043f78f8 R11: ffffffff81ac4d00 R12: ffffffff82232f7d
R13: ffffffff90e4e758 R14: ffffc900043f78a8 R15: 000000000001232f
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x27a/0x4f0
 cgroup_mkdir+0x277/0xe60
 kernfs_iop_mkdir+0x211/0x350
 vfs_mkdir+0x306/0x510
 do_mkdirat+0x247/0x590
 __x64_sys_mkdirat+0x87/0xa0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7d1158eba9
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:00007f7d124e1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f7d117d5fa0 RCX: 00007f7d1158eba9
RDX: 00000000000001ff RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007f7d11611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7d117d6038 R14: 00007f7d117d5fa0 R15: 00007ffcf90bb348
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g7409 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3065
rcu: rcu_preempt kthread starved for 10506 jiffies! g7409 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x12b/0x270
 rcu_gp_fqs_loop+0x301/0x1540
 rcu_gp_kthread+0x99/0x390
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
