On Wed, Dec 16, 2020 at 03:49:20PM +0200, Jarkko Sakkinen wrote: > Add synchronize_srcu_expedited() to sgx_encl_release() to catch a grace > period initiated by sgx_mmu_notifier_release(). > > A trivial example of a failing sequence with tasks A and B: > > 1. A: -> sgx_release() > 2. B: -> sgx_mmu_notifier_release() > 3. B: -> list_del_rcu() > 3. A: -> sgx_encl_release() > 4. A: -> cleanup_srcu_struct() > > The loop in sgx_release() observes an empty list because B has removed its > entry in the middle, and calls cleanup_srcu_struct() before B has a chance > to calls synchronize_srcu(). Leading to what? NULL ptr? https://lkml.kernel.org/r/X9e2jOWz1hfXVpQ5@xxxxxxxxxx already suggested that you should explain the bug better and add the splat but I'm still missing that explanation. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
