On Tue, Aug 27, 2019 at 06:03:46AM -0700, Maksim Yevmenkin wrote: > > > Hmm... interesting.... > > > > > > I only took a brief look at it. I suppose I can ensure user space address is wired and then copyout() can be called with mutex held > > > > >No, you cannot do this, at least without making the kernel to panic. > > User might unmap the wired mapping at any time still. > > Kostik, > > i was thinking along the lines of vslock/vsunlock and copyout_nofault. > basically similar to the sysctl code. do you think this would not > work? This would probably work, but at least causes fragmentation of userspace vm_map entries. If it is supposed to be used on high-frequency data path, then it would cause significant blow up of the VM structures used to keep user data map.Received on Tue Aug 27 2019 - 11:38:22 UTC
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