Re: [PATCH 11/12] mm: make userland page table freeing RCU-safe
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Date: 2026-09-01 14:03:58
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On Tue, Sep 01, 2026 at 02:33:14PM +0100, Kiryl Shutsemau wrote:
On Tue, Sep 01, 2026 at 12:01:31PM +0100, Lorenzo Stoakes (ARM) wrote:quoted
With this change in place the kernel policy is now that all page tables ares/all/userspace/ as subject implies?
Right yeah :) I hoped that the summary line would clarify that but can edit that also.
BTW, what is your take on kernel page tables? Do we want the same policy there. pagetable_free_kernel() is not RCU-safe as it is.
Yeah I think so too. I may follow up with a series to that effect also!
quoted
freed after an RCU grace period, and thus it is now safe to unconditionally perform page table walks under RCU, safe in the knowledge that page tables will not be freed underneath the walker.-- Kiryl Shutsemau / Kirill A. Shutemov
-- Cheers, Lorenzo