Re: KCSAN: data-race in __jbd2_journal_file_buffer / jbd2_journal_dirty_metadata

From: Jan Kara
Date: Tue Apr 06 2021 - 12:12:54 EST


On Tue 06-04-21 11:01:39, Theodore Ts'o wrote:
> On Tue, Apr 06, 2021 at 02:32:33PM +0200, Jan Kara wrote:
> > And the comment explains, why we do this unreliable check. Again, if we
> > wanted to silence KCSAN, we could use data_race() macro but AFAIU Ted isn't
> > very fond of that annotation.
>
> I'm not fond of the data_race macro, but I like bogus KCSAN reports
> even less. My main complaint is if we're going to have to put the
> data_race() macro in place, we're going to need to annotate each
> location with an explanation of why it's there (suppress a KCSAN false
> positive), and why's it's safe. If it's only one or two places, it'll
> probably be fine. If it's dozens, then I would say that KCSAN is
> becoming a net negative in terms of making the Linux kernel code
> maintainable.

OK, I'll send you patches for the two I've seen in the last month. We'll
see how many accumulate over time.

Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR