On Mon, Mar 13 2017 at 12:08pm -0400, Mike Snitzer <[email protected]> wrote:
> On Mon, Mar 13 2017 at 10:19am -0400, > Dan Carpenter <[email protected]> wrote: > > > Hello Milan Broz, > > > > This is a semi-automatic email about new static checker warnings. > > > > The patch 858516b7881e: "dm crypt: add cryptographic data integrity > > protection (authenticated encryption)" from Jan 4, 2017, leads to the > > following Smatch complaint: > > > > drivers/md/dm-crypt.c:1390 crypt_alloc_buffer() > > error: we previously assumed 'clone' could be null (see line 1362) > > > > drivers/md/dm-crypt.c > > 1361 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); > > 1362 if (!clone) > > ^^^^^^ > > We can be NULL on this path. > > > > 1363 goto return_clone; > > 1364 > > 1365 clone_init(io, clone); > > 1366 > > 1367 remaining_size = size; > > 1368 > > 1369 for (i = 0; i < nr_iovecs; i++) { > > 1370 page = mempool_alloc(cc->page_pool, gfp_mask); > > 1371 if (!page) { > > 1372 crypt_free_buffer_pages(cc, clone); > > 1373 bio_put(clone); > > 1374 gfp_mask |= __GFP_DIRECT_RECLAIM; > > 1375 goto retry; > > 1376 } > > 1377 > > 1378 len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE > > : remaining_size; > > 1379 > > 1380 bio_add_page(clone, page, len, 0); > > 1381 > > 1382 remaining_size -= len; > > 1383 } > > 1384 > > 1385 return_clone: > > 1386 if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) > > 1387 mutex_unlock(&cc->bio_alloc_lock); > > 1388 > > 1389 /* Allocate space for integrity tags */ > > 1390 if (dm_crypt_integrity_io_alloc(io, clone)) { > > ^^^^^ > > Oops inside new function call. > > > > 1391 crypt_free_buffer_pages(cc, clone); > > 1392 bio_put(clone); > > Thanks for the report. This code makes no sense as is. > > Milan, please help me understand why you're allocating memory needed for > integrity tags in this 'return_clone' error path. I folded in a fix for this, Milan please review crypt_alloc_buffer() changes in this revised commit: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.12&id=8896496efaef45ca1a734782a8d7f9082299fa5d -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
