syzbot

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!atomic_long_inc_not_zero(&event->refcount)
WARNING: kernel/events/core.c:10447 at __perf_event_overflow+0xb9e/0xec0 kernel/events/core.c:10447, CPU#1: syz.0.113/6382
Modules linked in:
CPU: 1 UID: 0 PID: 6382 Comm: syz.0.113 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__perf_event_overflow+0xb9e/0xec0 kernel/events/core.c:10447
Code: 90 36 00 4d 89 3e 4c 8b 7c 24 10 e9 c2 fc ff ff e8 27 43 ce ff 49 bd 00 00 00 00 00 fc ff df e9 08 fe ff ff e8 13 43 ce ff 90 <0f> 0b 90 e9 21 ff ff ff e8 05 43 ce ff 48 c7 c7 e0 11 b7 8b e8 f9
RSP: 0018:ffffc900049ff840 EFLAGS: 00010293
RAX: ffffffff81f6343d RBX: ffff88807b3ea6b0 RCX: ffff88802b2abd00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900049ff950 R08: ffff88807b3ea807 R09: 1ffff1100f67d500
R10: dffffc0000000000 R11: ffffed100f67d501 R12: ffff88807b3ea5b0
R13: dffffc0000000000 R14: ffff88807b3ea800 R15: 0000000000000000
FS:  00007fbae32da6c0(0000) GS:ffff8881257f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000076cce000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 perf_swevent_overflow kernel/events/core.c:10545 [inline]
 perf_swevent_event+0x323/0x650 kernel/events/core.c:-1
 do_perf_sw_event kernel/events/core.c:10685 [inline]
 ___perf_sw_event+0x4a6/0x730 kernel/events/core.c:10712
 __perf_sw_event+0xf9/0x1a0 kernel/events/core.c:10724
 perf_sw_event include/linux/perf_event.h:1596 [inline]
 do_user_addr_fault+0x12c4/0x1360 arch/x86/mm/fault.c:1281
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:__put_user_4+0xd/0x20 arch/x86/lib/putuser.S:94
Code: 66 89 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb <89> 01 31 c9 0f 01 ca e9 87 72 03 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900049ffe50 EFLAGS: 00050246
RAX: 0000000000000007 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8df3426e RDI: ffffffff8c073980
RBP: 0000000000000007 R08: ffffffff8213945f R09: ffff8880336e4cc0
R10: ffffc900049ffa08 R11: fffff5200093ff43 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000005
 __sys_socketpair+0xb7/0x560 net/socket.c:1797
 __do_sys_socketpair net/socket.c:1863 [inline]
 __se_sys_socketpair net/socket.c:1860 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1860
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbae239aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbae32da028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007fbae2615fa0 RCX: 00007fbae239aeb9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007fbae2408c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbae2616038 R14: 00007fbae2615fa0 R15: 00007ffcc4b9d3c8
 </TASK>
----------------
Code disassembly (best guess):
   0:	66 89 01             	mov    %ax,(%rcx)
   3:	31 c9                	xor    %ecx,%ecx
   5:	0f 01 ca             	clac
   8:	c3                   	ret
   9:	cc                   	int3
   a:	cc                   	int3
   b:	cc                   	int3
   c:	cc                   	int3
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	48 89 cb             	mov    %rcx,%rbx
  20:	48 c1 fb 3f          	sar    $0x3f,%rbx
  24:	48 09 d9             	or     %rbx,%rcx
  27:	0f 01 cb             	stac
* 2a:	89 01                	mov    %eax,(%rcx) <-- trapping instruction
  2c:	31 c9                	xor    %ecx,%ecx
  2e:	0f 01 ca             	clac
  31:	e9 87 72 03 00       	jmp    0x372bd
  36:	90                   	nop
  37:	90                   	nop
  38:	90                   	nop
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop