[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v3 01/16] perf: Ensure perf_guest_cbs aren't reloaded between !NULL check and deref



On 11/4/21 15:18, Sean Christopherson wrote:
If I'm interpeting Paolo's suggestion
correctly, he's pointing out that oustanding stores to the function pointers in
@cbs need to complete before assigning a non-NULL pointer to perf_guest_cbs,
otherwise a perf event handler may see a valid pointer with half-baked 
callbacks.

I think smp_store_release() with a comment would be appropriate, assuming my
above interpretation is correct.


Yes, exactly. It should even be rcu_assign_pointer(), matching the synchronize_rcu() in patch 1 (and the change can be done in patch 1, too).

Paolo




 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.