On Fri, Jun 24, 2016 at 10:40 AM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, Jun 24, 2016 at 10:21 AM, Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >> >> But as mentioned, I must have missed something. There were a number of >> places where the code used the task_stack_page() and >> task_thread_info() interchangably, which used to work and is no longer >> true. There might simply be cases I missed. > > .. and immediately as I wrote that, I went "Duh". > > One place I missed was free_thread_info(), which should now free the > stack, not the ti pointer. But it does > > struct page *page = virt_to_page(ti); > > and frees that, which is bogus. It turns out that we do do > > free_thread_info(tsk->stack); > > which is bogus too, and undoes it, but I think I have a few new places > to look at.. Try patching in this thing, which cleans up a bunch of that core crap: https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/commit/?h=x86/vmap_stack&id=7ca9fb6bbf2838cc94b2af41e94854d02649c58c It might not apply without the rest of my series, though. FWIW, your patch is much more lenient than my approach: I was planning prohibiting architectures from supplying their own struct thread_info if they put it in task_struct. To make that work, I have patches to remove everything but cpu, flags, and task from x86's thread_info first. I'm planning on tidying them up and sending them out after the vmap stack stuff lands in -tip -- I don't want to have big series that depend on each other flying around by email at the same time, because everyone will go nuts trying to figure out what applies where. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
