[PATCH 1/2] cpufreq/powernv: Fix use-after-free

[Michael Ellerman]

Andrew Donnellan <ajd at linux.ibm.com> writes:
> On 6/2/20 5:26 pm, Oliver O'Halloran wrote:
>> The cpufreq driver has a use-after-free that we can hit if:
>> 
>> a) There's an OCC message pending when the notifier is registered, and
>> b) The cpufreq driver fails to register with the core.
>> 
>> When a) occurs the notifier schedules a workqueue item to handle the
>> message. The backing work_struct is located on chips[].throttle and when b)
>> happens we clean up by freeing the array. Once we get to the (now free)
>> queued item and the kernel crashes.
>> 
>> Cc: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
>> Fixes: c5e29ea ("cpufreq: powernv: Fix bugs in powernv_cpufreq_{init/exit}")
>> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
>
> This sounds like it needs to go to stable.

I tagged it for stable when applying.

cheers