Re: [RFC][PATCH] x86/mm: Sync all vmalloc mappings before text_poke()

Steven Rostedt
2020-05-01T01:13:13Z

[ Joerg, sending again this time not just to you. (hit reply to sender
and not reply to all). Feel free to resend what you wrote before to this ]

On Thu, 30 Apr 2020 21:14:34 +0200
Joerg Roedel <jroedel@suse.de> wrote:

> And alloc_percpu() calls down into pcpu_alloc(), which allocates new
> percpu chunks using vmalloc() on x86. And there we are again in the
> vmalloc area.

So after a vmalloc() is made, should the page tables be synced?

This is a rather subtle bug, and I don't think it should be the caller of
percpu_alloc() that needs to call vmalloc_sync_mappings().

What's your suggestion for a fix?

-- Steve