No idea on the problem itself because I don't understand it, just:

quoted text
> Given that, we either need to address the const requirement
> for userspace, alter userspace's usage, or find another way to address
> the deadlock.  Any ideas?

In the worst case you can always disable the vsyscall gtod() and
thus the need for a user space safe seqlock_t, but it will
hurt some workloads significantly. 

-Andi

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