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Date: Thu, 2 May 2024 17:41:23 -0700
From: Kees Cook <keescook@chromium.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
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Subject: Re: [PATCH 5/5] fs: Convert struct file::f_count to refcount_long_t
Message-ID: <202405021736.574A688@keescook>
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On Fri, May 03, 2024 at 01:14:45AM +0100, Al Viro wrote:
> On Thu, May 02, 2024 at 05:10:18PM -0700, Kees Cook wrote:
> 
> > But anyway, there needs to be a general "oops I hit 0"-aware form of
> > get_file(), and it seems like it should just be get_file() itself...
> 
> ... which brings back the question of what's the sane damage mitigation
> for that.  Adding arseloads of never-exercised failure exits is generally
> a bad idea - it's asking for bitrot and making the thing harder to review
> in future.

Linus seems to prefer best-effort error recovery to sprinkling BUG()s
around.  But if that's really the solution, then how about get_file()
switching to to use inc_not_zero and BUG on 0?

-- 
Kees Cook