Hi Dan.
The updated patch has landed in mainline, as per :
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=86dc40c7ea9c22f64571e0e45f695de73a0e2644
On Mon, Nov 29, 2021 at 2:00 PM Dan Carpenter <dan.carpen...@oracle.com> wrote:
>
> Hello Alex Williamson,
>
> The patch edad96db58d2: "iommu/vt-d: Fix unmap_pages support" from
> Nov 22, 2021, leads to the following Smatch static checker warning:
>
> drivers/iommu/intel/iommu.c:1369 dma_pte_clear_level()
> error: uninitialized symbol 'level_pfn'.
>
> drivers/iommu/intel/iommu.c
> 1330 static struct page *dma_pte_clear_level(struct dmar_domain *domain,
> int level,
> 1331 struct dma_pte *pte,
> unsigned long pfn,
> 1332 unsigned long start_pfn,
> 1333 unsigned long last_pfn,
> 1334 struct page *freelist)
> 1335 {
> 1336 struct dma_pte *first_pte = NULL, *last_pte = NULL;
> 1337
> 1338 pfn = max(start_pfn, pfn);
> 1339 pte = &pte[pfn_level_offset(pfn, level)];
> 1340
> 1341 do {
> 1342 unsigned long level_pfn;
> 1343
> 1344 if (!dma_pte_present(pte))
> 1345 goto next;
> ^^^^^^^^^^
>
> If we ever hit this goto then there is going to be a bug.
>
> 1346
> 1347 level_pfn = pfn & level_mask(level);
> 1348
> 1349 /* If range covers entire pagetable, free it */
> 1350 if (start_pfn <= level_pfn &&
> 1351 last_pfn >= level_pfn + level_size(level) - 1) {
> 1352 /* These suborbinate page tables are going
> away entirely. Don't
> 1353 bother to clear them; we're just going to
> *free* them. */
> 1354 if (level > 1 && !dma_pte_superpage(pte))
> 1355 freelist =
> dma_pte_list_pagetables(domain, level - 1, pte, freelist);
> 1356
> 1357 dma_clear_pte(pte);
> 1358 if (!first_pte)
> 1359 first_pte = pte;
> 1360 last_pte = pte;
> 1361 } else if (level > 1) {
> 1362 /* Recurse down into a level that isn't
> *entirely* obsolete */
> 1363 freelist = dma_pte_clear_level(domain, level
> - 1,
> 1364
> phys_to_virt(dma_pte_addr(pte)),
> 1365 level_pfn,
> start_pfn, last_pfn,
> 1366 freelist);
> 1367 }
> 1368 next:
> --> 1369 pfn = level_pfn + level_size(level);
> ^^^^^^^^^
>
> 1370 } while (!first_pte_in_page(++pte) && pfn <= last_pfn);
> 1371
> 1372 if (first_pte)
> 1373 domain_flush_cache(domain, first_pte,
> 1374 (void *)++last_pte - (void
> *)first_pte);
> 1375
> 1376 return freelist;
> 1377 }
>
> regards,
> dan carpenter
> _______________________________________________
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> iommu@lists.linux-foundation.org
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