On Tue, May 09, 2023 at 10:37:12AM -0700, Linus Torvalds wrote:
> In fs/btrfs/extent_io.c, we have
> 
>     while (index <= end_index) {
>         folio = filemap_get_folio(mapping, index);
>         filemap_dirty_folio(mapping, folio);
> 

I have re-worked the Smatch check for warnings about dereferencing
error pointer so now it warns about that:

fs/btrfs/extent_io.c:224 extent_range_redirty_for_io() error: 'folio' dereferencing possible ERR_PTR()

I've also made a list of functions which don't necessarily need to be
checked so it's easy to silence false positives now.
https://github.com/error27/smatch/blob/master/check_err_ptr_deref.c

regards,
dan carpenter