Re: [PATCH] gfs2: Fix error pointer dereference
Matthew Wilcox <[email protected]>
| Newsgroups | dev.linux.lists.gfs2,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On Wed, Feb 18, 2026 at 02:06:45PM -0600, Ethan Tidmore wrote:
> The function __filemap_get_folio() can return an error pointer and is
> not checked for one. Add check for error pointer.
Can you explain how __filemap_get_folio() would fail, given the
presence of __GFP_NOFAIL in the GFP flags?
> Detected by Smatch:
> fs/gfs2/meta_io.c:147 gfs2_getbuf() error:
> 'folio' dereferencing possible ERR_PTR()
>
> Fixes: 0eb751791df86 ("gfs2: convert gfs2_getbuf() to folios")
> Signed-off-by: Ethan Tidmore <[email protected]>
> ---
> fs/gfs2/meta_io.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
> index 3c8e4553102d..9c0ba4c3cb29 100644
> --- a/fs/gfs2/meta_io.c
> +++ b/fs/gfs2/meta_io.c
> @@ -144,6 +144,8 @@ struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
> folio = __filemap_get_folio(mapping, index,
> FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
> mapping_gfp_mask(mapping) | __GFP_NOFAIL);
> + if (IS_ERR(folio))
> + return NULL;
> bh = folio_buffers(folio);
> if (!bh)
> bh = create_empty_buffers(folio,
> --
> 2.53.0
>