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	Thu, 02 May 2024 22:42:50 +0000
Date: Thu, 2 May 2024 23:42:50 +0100
From: Al Viro <viro@zeniv.linux.org.uk>
To: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
	linux-fsdevel@vger.kernel.org, Zack Rusin <zack.rusin@broadcom.com>,
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Subject: Re: [PATCH 5/5] fs: Convert struct file::f_count to refcount_long_t
Message-ID: <20240502224250.GM2118490@ZenIV>
References: <20240502222252.work.690-kees@kernel.org>
 <20240502223341.1835070-5-keescook@chromium.org>
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Thu, May 02, 2024 at 03:33:40PM -0700, Kees Cook wrote:
> Underflow of f_count needs to be more carefully detected than it
> currently is. The results of get_file() should be checked, but the
> first step is detection. Redefine f_count from atomic_long_t to
> refcount_long_t.

	It is used on fairly hot paths.  What's more, it's not
at all obvious what the hell would right semantics be.

NAKed-by: Al Viro <viro@zeniv.linux.org.uk>