Hello.
We are Ubisectech Sirius Team, the vulnerability lab of China ValiantSec. Recently, our team has discovered a issue in Linux kernel 6.11.0-rc2-g6a0e38264012. Attached to the email were a PoC file of the issue.

Stack dump:

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WARNING: CPU: 0 PID: 13222 at arch/x86/events/intel/lbr.c:957 intel_pmu_lbr_counters_reorder.isra.0+0x61f/0x750 arch/x86/events/intel/lbr.c:957
Modules linked in:
CPU: 0 UID: 0 PID: 13222 Comm: syz.3.335 Not tainted 6.11.0-rc2-g6a0e38264012 #49
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:intel_pmu_lbr_counters_reorder.isra.0+0x61f/0x750 arch/x86/events/intel/lbr.c:957
Code: 00 48 8d bb 20 01 00 00 48 89 f8 48 c1 e8 03 42 80 3c 20 00 0f 84 26 ff ff ff e8 ac 96 df 00 e9 1c ff ff ff e8 22 cd 83 00 90 <0f> 0b 90 e9 80 fb ff ff 48 c7 c7 60 87 6c 8d e8 0d c0 8e 03 e9 79
RSP: 0000:ffffc90001d77910 EFLAGS: 00010046
RAX: 0000000080110000 RBX: ffff888000155070 RCX: ffffffff8105486e
RDX: ffff888043692500 RSI: ffffffff81054cee RDI: 0000000000000005
RBP: ffff888000155070 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff88802c622bb8 R15: 0000000000000000
FS:  00007f3f01bc8640(0000) GS:ffff88802c600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002001d000 CR3: 000000005c572000 CR4: 0000000000750ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
PKRU: 55555554
Call Trace:
 <TASK>
 intel_pmu_lbr_save_brstack+0x1ef/0x3b0 arch/x86/events/intel/lbr.c:976
 handle_pmi_common+0x744/0xbd0 arch/x86/events/intel/core.c:3118
 intel_pmu_handle_irq+0x2b7/0x10b0 arch/x86/events/intel/core.c:3181
 perf_event_nmi_handler arch/x86/events/core.c:1747 [inline]
 perf_event_nmi_handler+0x4c/0x70 arch/x86/events/core.c:1733
 nmi_handle+0x1a6/0x5b0 arch/x86/kernel/nmi.c:151
 default_do_nmi+0x88/0x220 arch/x86/kernel/nmi.c:351
 exc_nmi+0x262/0x310 arch/x86/kernel/nmi.c:545
 asm_exc_nmi+0xb8/0x101 arch/x86/entry/entry_64.S:1192
RIP: 0033:0x7f3f00c4a51a
Code: 00 00 00 ff 89 81 90 00 00 00 75 04 85 c0 74 1c 48 63 44 24 18 48 8d 14 80 48 8d 14 50 48 8d 05 6c 16 25 00 48 83 7c d0 28 00 <74> 0f 48 8b 44 24 08 c7 80 90 00 00 00 16 00 00 00 48 8b 54 24 08
RSP: 002b:00007f3f01bc7fc0 EFLAGS: 00000246
RAX: 00007f3f00e9bb80 RBX: 00007f3f00f35f80 RCX: 00007f3f00f35f80
RDX: 0000000000007a81 RSI: 0000000000000000 RDI: 0000000020000300
RBP: 00007f3f00e1bd8a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3f00f35f80 R15: 00007f3f01ba8000
 </TASK>

Thank you for taking the time to read this email and we look forward to working with you further.