From: Dev Jain <dev.jain@arm.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: jroedel@suse.de, akpm@linux-foundation.org, ryan.roberts@arm.com,
david@redhat.com, hch@lst.de, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] mm: Update mask post pxd_clear_bad()
Date: Fri, 14 Mar 2025 18:27:43 +0530 [thread overview]
Message-ID: <acba6a71-4ee8-445a-aae9-822f88079cb3@arm.com> (raw)
In-Reply-To: <Z9NDkFzSj-vnvGOy@casper.infradead.org>
On 14/03/25 2:14 am, Matthew Wilcox wrote:
> On Thu, Mar 13, 2025 at 11:44:14PM +0530, Dev Jain wrote:
>> Since pxd_clear_bad() is an operation changing the state of the page tables,
>> we should call arch_sync_kernel_mappings() post this.
>
> Could you explain why? What effect does not calling
> arch_sync_kernel_mappings() have in this case?
Apologies, I again forgot to explain the userspace effect.
I just found this by code inspection, using the logic the fixes commit
uses: we should sync when we change the pxd.
The question I have been pondering on is, what is the use of the
pxd_bad() macros, when do we actually hit a bad state, and why don't we
just trigger a BUG when we hit pxd_bad()?
prev parent reply other threads:[~2025-03-14 12:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-13 18:14 Dev Jain
2025-03-13 18:28 ` Dev Jain
2025-03-14 14:27 ` Yeo Reum Yun
2025-03-17 7:03 ` Dev Jain
2025-03-13 20:44 ` Matthew Wilcox
2025-03-14 12:57 ` Dev Jain [this message]
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