Re: [PATCH v4] rust: cpufreq: reject NULL from cpufreq_cpu_get()

[Viresh Kumar]

On 01-10-26, 13:19, Mehmet Koseoglu wrote:
> cpufreq_cpu_get() returns either a referenced policy or NULL.
> PolicyCpu::from_cpu() passed its return value to from_err_ptr(), which
> rejects ERR_PTR values but accepts NULL.
> 
> If the lookup fails, Policy::from_raw_mut() therefore constructs a mutable
> reference from NULL. Dropping the resulting PolicyCpu then passes the
> invalid pointer to cpufreq_cpu_put(), causing an oops in kobject_put().
> 
> Reject NULL with NonNull before constructing the Policy reference. Return
> ENODEV instead.
> 
> A KUnit negative-control run reproduced the oops with the original
> conversion. The same test passed with this change. The reproducer is
> available on request.
> 
> Fixes: 6ebdd7c93177 ("rust: cpufreq: Extend abstractions for policy and driver ops")
> Cc: stable@xxxxxxxxxxxxxxx
> Assisted-by: LLM
> Signed-off-by: Mehmet Koseoglu <mehmet.mkoseoglu@xxxxxxxxx>
> Reviewed-by: Onur Özkan <work@xxxxxxxxxxxxx>
> Reviewed-by: spidermana <xuyiwen14@xxxxxxxxx>

Applied. Thanks.

-- 
viresh