On Wed, Aug 2, 2023 at 9:35 AM Dan Carpenter <dan.carpen...@linaro.org> wrote:
> Hello Andreas Gruenbacher,
>
> The patch 8f18190e3173: "gfs2: Use mapping->gfp_mask for metadata
> inodes" from Jul 26, 2023 (linux-next), leads to the following Smatch
> static checker warning:
>
> fs/gfs2/inode.c:286 gfs2_lookup_simple()
> error: 'inode' dereferencing possible ERR_PTR()
>
> fs/gfs2/inode.c
> 268 struct inode *gfs2_lookup_simple(struct inode *dip, const char *name)
> 269 {
> 270 struct qstr qstr;
> 271 struct inode *inode;
> 272 gfs2_str2qstr(&qstr, name);
> 273 inode = gfs2_lookupi(dip, &qstr, 1);
> 274 /* gfs2_lookupi has inconsistent callers: vfs
> 275 * related routines expect NULL for no entry found,
> 276 * gfs2_lookup_simple callers expect ENOENT
> 277 * and do not check for NULL.
>
> This comment is ancient. I think how gfs2_lookupi() works is that if
> there is an error it returns an error code, but if the file does not
> exist it returns NULL. (This is just based on vague assumptions about
> how mixed error pointer/NULL functions work).
>
> 278 */
> 279 if (inode == NULL)
> 280 return ERR_PTR(-ENOENT);
> 281
> 282 /*
> 283 * Must not call back into the filesystem when allocating
> 284 * pages in the metadata inode's address space.
> 285 */
> --> 286 mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
> ^^^^^^^^^^^^^^^^
> error pointer dereference
Ah, right, thanks for pointing this out. I've pushed a fix.
Andreas
> 287
> 288 return inode;
> 289 }
>
> regards,
> dan carpenter
