perf/x86: Guard intel_pmu_cpu_dead() against invalid hybrid PMU casts

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In failure paths, cpuc->pmu can still point to the global static pmu
instead of an embedded x86_hybrid_pmu::pmu. Calling hybrid_pmu() on
that pointer causes an invalid container conversion and may lead to
out-of-bounds access.

This can happen in at least two cases:
- init_hybrid_pmu() fails check_hw_exists() and leaves cpuc->pmu as-is.
- CPU hotplug fails between CPUHP_PERF_X86_PREPARE and
CPUHP_AP_PERF_X86_STARTING, and rollback invokes intel_pmu_cpu_dead().

Fix both paths by:
- Clear cpuc->pmu to NULL when check_hw_exists() fails.
- Validat that cpuc->pmu is not the global static pmu before calling
  hybrid_pmu() in intel_pmu_cpu_dead().

A new helper x86_get_static_pmu() is added to get the global static pmu.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Reviewed-by: Zide Chen <zide.chen@intel.com>
Link: https://patch.msgid.link/20260717080342.1879573-4-dapeng1.mi@linux.intel.com

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Dapeng Mi 2026-07-17 16:03:37 +08:00 • committed by Peter Zijlstra

parent 96746e731e

commit 278a3731c9

3 changed files with 11 additions and 2 deletions

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5

arch/x86/events/core.c

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7

arch/x86/events/intel/core.c

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1

arch/x86/events/perf_event.h

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