Hi,

While testing the 6.16.0-rc2 kernel on an AArch64 QEMU environment on the, I
encountered a warning followed by a soft lockup that seems to be triggered by a
bad PMU index access and a circular locking dependency. This was observed during
perf_event_open() execution triggered by syzkaller.

Here's a summary of the issue:

---

WARNING: possible circular locking dependency detected

 Chain exists of:
   console_owner --> &rq->__lock --> &ctx->lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&ctx->lock);
                                lock(&rq->__lock);
                                lock(&ctx->lock);
   lock(console_owner);

---

And this happens while the system is handling a perf event overflow and trying to
update PMU counters or start/stop events.

Environment:
- Kernel: v6.16.0-rc2
- Platform: QEMU aarch64 (KVM enabled Radxa's Orion6 platform.)
- Arm64 PMU focused kernel fuzzing with perf_event_open, based on syzkaller
- No additional modules loaded

The issue is reproducible, and for detailed reproduction steps, please refer to
Link: https://lore.kernel.org/lkml/20250723104359.364547-5-ysk@kzalloc.com/

I’ve attached the original log from the lockup as well as the decoded version.

Best regards,
Yunseong Kim