From: Dan Carpenter <dan.carpenter@linaro.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: gfs2@lists.linux.dev
Subject: Re: [bug report] gfs2: Convert gfs2_jhead_process_page() to use a folio
Date: Fri, 13 Oct 2023 09:28:32 +0300 [thread overview]
Message-ID: <efb41d72-c254-46b6-8de5-dcd9d3ef8887@kadam.mountain> (raw)
In-Reply-To: <ZSgQe27OCfUpmsbS@casper.infradead.org>
On Thu, Oct 12, 2023 at 04:27:55PM +0100, Matthew Wilcox wrote:
> On Thu, Oct 12, 2023 at 12:43:34PM +0300, Dan Carpenter wrote:
> > Hello Matthew Wilcox (Oracle),
> >
> > The patch 240159077d00: "gfs2: Convert gfs2_jhead_process_page() to
> > use a folio" from May 13, 2022 (linux-next), leads to the following
> > Smatch static checker warning:
> >
> > fs/gfs2/lops.c:485 gfs2_jhead_process_page()
> > error: 'folio' dereferencing possible ERR_PTR()
> >
> > fs/gfs2/lops.c
> > 469 static void gfs2_jhead_process_page(struct gfs2_jdesc *jd, unsigned long index,
> > 470 struct gfs2_log_header_host *head,
> > 471 bool *done)
> > 472 {
> > 473 struct folio *folio;
> > 474
> > 475 folio = filemap_get_folio(jd->jd_inode->i_mapping, index);
> >
> > Does filemap_get_folio() need to be checked for errors?
>
> In this specific case, we know that the folio is there and will always
> be returned. See the comment on line 484. Can I annotate this call so
> that the tool knows this is a special case and doesn't warn about it?
>
Thanks for looking at this. There is no annotation. In the kernel we
are very good at fixing static checker warnings so everything old is a
false positive.
This one is from May but I recently changed how dereferences were
handled so it's the first time I had seen the warning.
regards,
dan carpenter
prev parent reply other threads:[~2023-10-13 6:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-12 9:43 [bug report] gfs2: Convert gfs2_jhead_process_page() to use a folio Dan Carpenter
2023-10-12 15:27 ` Matthew Wilcox
2023-10-13 6:28 ` Dan Carpenter [this message]
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