------------[ cut here ]------------
failed to allocate ring buffer on CPU 3
WARNING: kernel/trace/ring_buffer.c:8094 at trace_rb_cpu_prepare+0x463/0x520 kernel/trace/ring_buffer.c:8094, CPU#0: syz.0.398/6963
Modules linked in:
CPU: 0 UID: 0 PID: 6963 Comm: syz.0.398 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:trace_rb_cpu_prepare+0x465/0x520 kernel/trace/ring_buffer.c:8094
Code: 48 c1 ea 03 80 3c 02 00 0f 84 bc fc ff ff 48 8b 3c 24 e8 ae f1 74 00 e9 ae fc ff ff e8 84 80 fb ff 48 8d 3d bd 66 5c 10 89 ee <67> 48 0f b9 3a bb f4 ff ff ff e9 d3 fd ff ff 4c 89 ef e8 84 f1 74
RSP: 0000:ffffc90020cdf8b8 EFLAGS: 00010246
RAX: 0000000000080000 RBX: ffff8880512d14b8 RCX: ffffc90007881000
RDX: 0000000000080000 RSI: 0000000000000003 RDI: ffffffff926ebec0
RBP: 0000000000000003 R08: ffff8880282f2018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000003
R13: ffff8880512d1410 R14: 0000000000000162 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888095279000(0063) knlGS:00000000f53c6b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f71895d0 CR3: 000000004cb53000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 cpuhp_invoke_callback+0x205/0x9a0 kernel/cpu.c:204
 cpuhp_issue_call+0x1b8/0x970 kernel/cpu.c:2354
 __cpuhp_state_add_instance_cpuslocked+0x2d7/0x400 kernel/cpu.c:2423
 __cpuhp_state_add_instance+0xd5/0x2d0 kernel/cpu.c:2444
 cpuhp_state_add_instance include/linux/cpuhotplug.h:377 [inline]
 alloc_buffer+0x53b/0x1610 kernel/trace/ring_buffer.c:2922
 __ring_buffer_alloc+0x2d/0x40 kernel/trace/ring_buffer.c:2964
 allocate_trace_buffer+0x150/0xa30 kernel/trace/trace.c:8535
 allocate_trace_buffers kernel/trace/trace.c:8568 [inline]
 trace_array_create_systems+0x582/0xc30 kernel/trace/trace.c:8746
 trace_array_create kernel/trace/trace.c:8789 [inline]
 instance_mkdir+0xca/0x140 kernel/trace/trace.c:8804
 tracefs_syscall_mkdir+0x10e/0x180 fs/tracefs/inode.c:121
 vfs_mkdir+0x36d/0x8a0 fs/namei.c:5428
 filename_mkdirat+0x4c4/0x630 fs/namei.c:5461
 __do_sys_mkdirat fs/namei.c:5482 [inline]
 __se_sys_mkdirat fs/namei.c:5479 [inline]
 __ia32_sys_mkdirat+0x88/0xc0 fs/namei.c:5479
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x14b/0x8c0 arch/x86/entry/syscall_32.c:282
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:307
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf73aefbc
Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 58 b8
RSP: 002b:00000000f53c650c EFLAGS: 00000292 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000080000180
RDX: 00000000000001ff RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	48 c1 ea 03          	shr    $0x3,%rdx
   4:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   8:	0f 84 bc fc ff ff    	je     0xfffffcca
   e:	48 8b 3c 24          	mov    (%rsp),%rdi
  12:	e8 ae f1 74 00       	call   0x74f1c5
  17:	e9 ae fc ff ff       	jmp    0xfffffcca
  1c:	e8 84 80 fb ff       	call   0xfffb80a5
  21:	48 8d 3d bd 66 5c 10 	lea    0x105c66bd(%rip),%rdi        # 0x105c66e5
  28:	89 ee                	mov    %ebp,%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	bb f4 ff ff ff       	mov    $0xfffffff4,%ebx
  34:	e9 d3 fd ff ff       	jmp    0xfffffe0c
  39:	4c 89 ef             	mov    %r13,%rdi
  3c:	e8                   	.byte 0xe8
  3d:	84 f1                	test   %dh,%cl
  3f:	74                   	.byte 0x74