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From: asmadeus@codewreck.org
To: Christian Schoenebeck <linux_oss@crudebyte.com>
Cc: Eric Van Hensbergen <ericvh@kernel.org>,
	Latchesar Ionkov <lucho@ionkov.net>,
	Chris Arges <carges@cloudflare.com>,
	v9fs@lists.linux.dev, linux-kernel@vger.kernel.org,
	David Howells <dhowells@redhat.com>,
	Matthew Wilcox <willy@infradead.org>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] 9p/virtio: restrict page pinning to user_backed_iter() iovec
Date: Thu, 18 Dec 2025 06:49:04 +0900	[thread overview]
Message-ID: <aUMlUDBnBs8Bdqg0@codewreck.org> (raw)
In-Reply-To: <2332946.iZASKD2KPV@weasel>

Christian Schoenebeck wrote on Wed, Dec 17, 2025 at 02:41:31PM +0100:
> Something's seriously messed up with 9p cache right now. With today's git 
> master I do get data corruption in any 9p cache mode, including cache=mmap, 
> only cache=none behaves clean.

Ugh...

> With this patch applied though it gets even worse as I can't even boot due to 
> immediate 9p data corruption. Could be coincidence, as I get corruption 
> without this patch in any cache mode as well, but at least I have to try much 
> harder to trigger it.

As said before don't bother with this patch, it's definitely wrong --
we can't just use data->kvec->iov_base for bvec or folioq iters, so
there *will* be corruptions with this patch.

I'll try to see if I can produce anything wrong with master...
-- 
Dominique

      reply	other threads:[~2025-12-17 21:49 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-09 21:04 [PATCH] 9p/virtio: restrict page pinning to user_backed_iter() iovec Dominique Martinet via B4 Relay
2025-12-10  4:21 ` Matthew Wilcox
2025-12-10  6:04 ` Christoph Hellwig
2025-12-10  7:38   ` asmadeus
2025-12-10  8:32     ` Christoph Hellwig
2025-12-13 13:28       ` asmadeus
2025-12-15  5:55         ` Christoph Hellwig
2025-12-15  7:34           ` Dominique Martinet
2025-12-15 11:16             ` Christian Schoenebeck
2025-12-15 14:37             ` Christoph Hellwig
2025-12-10 13:33   ` Christian Schoenebeck
2025-12-17 13:41 ` Christian Schoenebeck
2025-12-17 21:49   ` asmadeus [this message]

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