Re: [PATCH RESEND] powercap: intel_rapl: Fix kernel panic during PMU unbind

[Rafael J. Wysocki (Intel)]

On Mon, Aug 24, 2026 at 9:35 AM Abel Vesa <abel.vesa@xxxxxxxxxxxxxxxx> wrote:
>
> On 26-08-22 15:16:57, Sumeet Pawnikar wrote:
> > From: Sumeet Pawnikar <sumeet4linux@xxxxxxxxx>
> >
> > 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@xxxxxxxxx>
>
> Looks OK to me, so:
>
> Reviewed-by: Abel Vesa <abel.vesa@xxxxxxxxxxxxxxxx>

Applied as 7.3-rc material, thanks!