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powercap: intel_rapl: Fix kernel panic during PMU unbind

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rapl_package_add_pmu() fails internally at perf_pmu_register(),
and rapl_pmu_update() leaves the global rapl_pmu.pmu structure
zero-initialized via memset and returns an error. But any
previously probed packages retain has_pmu = true.

When the driver is subsequently unbound or removed,
rapl_package_remove_pmu_locked() sees has_pmu == true and
unconditionally calls perf_pmu_unregister(&rapl_pmu.pmu) on the
zeroed-out structure. This attempts a list_del_rcu() on a NULL
list head, immediately causing a kernel panic.

Fix this by checking if the PMU is actually registered before
attempting to unregister it.

Signed-off-by: Sumeet Pawnikar <sumeet4linux@gmail.com>
Reviewed-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
[ rjw: Added empty line after the new conditional ]
Link: https://patch.msgid.link/20260822094657.12489-1-sumeet4linux@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Sumeet Pawnikar 2026-08-22 15:16:57 +05:30 committed by Rafael J. Wysocki
parent a8b842366f
commit 916b61abba
1 changed files with 3 additions and 1 deletions
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4
drivers/powercap/intel_rapl_common.c
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@ -1661,7 +1661,9 @@ void rapl_package_remove_pmu_locked(struct rapl_package *rp)
return;
}
perf_pmu_unregister(&rapl_pmu.pmu);
if (rapl_pmu.registered)
perf_pmu_unregister(&rapl_pmu.pmu);
memset(&rapl_pmu, 0, sizeof(struct rapl_pmu));
}
EXPORT_SYMBOL_NS_GPL(rapl_package_remove_pmu_locked, "INTEL_RAPL");