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From: Matthew Wilcox <willy@infradead.org>
To: Theodore Tso <tytso@mit.edu>
Cc: Deepanshu Kartikey <kartikey406@gmail.com>,
	Zhang Yi <yi.zhang@huaweicloud.com>,
	linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzbot+b0a0670332b6b3230a0a@syzkaller.appspotmail.com,
	adilger.kernel@dilger.ca, djwong@kernel.org
Subject: Re: [PATCH v2] ext4: check folio uptodate state in ext4_page_mkwrite()
Date: Wed, 3 Dec 2025 21:54:53 +0000	[thread overview]
Message-ID: <aTCxrXtrtB0x9C8X@casper.infradead.org> (raw)
In-Reply-To: <20251203154657.GC93777@macsyma.lan>

On Wed, Dec 03, 2025 at 10:46:57AM -0500, Theodore Tso wrote:
> Matthew, as the page cache maintainer, do we actually need this extra
> rigamarole.  Or can we just skip taking the lock before checking to
> see if the folio is uptodate in ext4_page_mkwrite()?

Oh, this triggered a memory.  Looks like you missed my reply in that
thread.  This patch is bogus.  You need to prevent !uptodate folios from
being referenced by the page tables.

https://groups.google.com/g/syzkaller-bugs/c/kjaCOwdrWVg/m/6Li1dROPBQAJ

      parent reply	other threads:[~2025-12-03 21:54 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-22  1:57 [PATCH v2] ext4: check folio uptodate state in ext4_page_mkwrite() Deepanshu Kartikey
2025-11-30  2:06 ` Deepanshu Kartikey
2025-12-02 12:24   ` Zhang Yi
2025-12-03  1:37     ` Deepanshu Kartikey
2025-12-03  6:52       ` Zhang Yi
2025-12-03  7:43         ` Deepanshu Kartikey
2025-12-03 15:46           ` Theodore Tso
2025-12-03 17:04             ` Deepanshu Kartikey
2025-12-03 18:40             ` Theodore Tso
2025-12-03 21:35             ` Matthew Wilcox
2025-12-03 22:33               ` Theodore Tso
2025-12-04  9:54                 ` Deepanshu Kartikey
2025-12-05  2:18                   ` Theodore Tso
2025-12-05  3:31                     ` Deepanshu Kartikey
2025-12-05  3:33                     ` Matthew Wilcox
2025-12-05 13:37                       ` Theodore Tso
2025-12-05 14:28                         ` Deepanshu Kartikey
2026-01-05  2:08                           ` Deepanshu Kartikey
2025-12-03 21:54             ` Matthew Wilcox [this message]

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