On Tue, Sep 22, 2015 at 11:37 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > kinds of mess. > > I don't think that anyone really wants to move #PF to IST, which means > that we simply cannot handle vmalloc faults that happen when switching > stacks after SYSCALL, no matter what fanciness we shove into the > page_fault asm. But that's fine. The kernel stack is special. So yes, we want to make sure that the kernel stack is always mapped in the thread whose stack it is. But that's not a big and onerous guarantee to make. Not when the *real* problem is "random vmalloc allocations made by other processes that we are not in the least interested in, and we don't want to add synchronization for". Linus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>