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 <sva...@linux.vnet.ibm.com>
Fixes: c5e29ea ("cpufreq: powernv: Fix bugs in powernv_cpufreq_{init/exit}")
Signed-off-by: Oliver O'Halloran <ooh...@gmail.com>

This sounds like it needs to go to stable.


--
Andrew Donnellan              OzLabs, ADL Canberra
a...@linux.ibm.com             IBM Australia Limited

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