On Tue, May 14, 2019 at 07:21:33AM +0000, Nadav Amit wrote: > > On May 14, 2019, at 12:15 AM, Jan Stancek <jstancek@xxxxxxxxxx> wrote: > > Replacing fullmm with need_flush_all, brings the problem back / reproducer hangs. > > Maybe setting need_flush_all does not have the right effect, but setting > fullmm and then calling __tlb_reset_range() when the PTEs were already > zapped seems strange. > > fullmm is described as: > > /* > * we are in the middle of an operation to clear > * a full mm and can make some optimizations > */ > > And this not the case. Correct; starting with fullmm would be wrong. For instance tlb_start_vma() would do the wrong thing because it assumes the whole mm is going away. But we're at tlb_finish_mmu() time and there the difference doesn't matter anymore. But yes, that's a wee abuse.
