* [linux-next:master 2984/3632] drivers/iommu/intel/iommu.c:1344:7: warning: variable 'level_pfn' is used uninitialized whenever 'if' condition is true
@ 2021-11-26 1:34 kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2021-11-26 1:34 UTC (permalink / raw)
To: Alex Williamson
Cc: llvm, kbuild-all, Linux Memory Management List, Joerg Roedel, Lu Baolu
tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head: f81e94e91878bded599cc60f2881cfd50991aeb9
commit: edad96db58d2f0b666ddd0a3e0f179e586f5f66a [2984/3632] iommu/vt-d: Fix unmap_pages support
config: x86_64-buildonly-randconfig-r004-20211126 (https://download.01.org/0day-ci/archive/20211126/202111260939.DmjPLz34-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 0332d105b9ad7f1f0ffca7e78b71de8b3a48f158)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=edad96db58d2f0b666ddd0a3e0f179e586f5f66a
git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git fetch --no-tags linux-next master
git checkout edad96db58d2f0b666ddd0a3e0f179e586f5f66a
# save the config file to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> drivers/iommu/intel/iommu.c:1344:7: warning: variable 'level_pfn' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!dma_pte_present(pte))
^~~~~~~~~~~~~~~~~~~~~
drivers/iommu/intel/iommu.c:1369:9: note: uninitialized use occurs here
pfn = level_pfn + level_size(level);
^~~~~~~~~
drivers/iommu/intel/iommu.c:1344:3: note: remove the 'if' if its condition is always false
if (!dma_pte_present(pte))
^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/iommu/intel/iommu.c:1342:26: note: initialize the variable 'level_pfn' to silence this warning
unsigned long level_pfn;
^
= 0
drivers/iommu/intel/iommu.c:136:29: warning: unused function 'dma_to_mm_pfn' [-Wunused-function]
static inline unsigned long dma_to_mm_pfn(unsigned long dma_pfn)
^
2 warnings generated.
vim +1344 drivers/iommu/intel/iommu.c
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1329
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1330 static struct page *dma_pte_clear_level(struct dmar_domain *domain, int level,
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1331 struct dma_pte *pte, unsigned long pfn,
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1332 unsigned long start_pfn,
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1333 unsigned long last_pfn,
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1334 struct page *freelist)
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1335 {
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1336 struct dma_pte *first_pte = NULL, *last_pte = NULL;
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1337
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1338 pfn = max(start_pfn, pfn);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1339 pte = &pte[pfn_level_offset(pfn, level)];
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1340
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1341 do {
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1342 unsigned long level_pfn;
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1343
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 @1344 if (!dma_pte_present(pte))
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1345 goto next;
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1346
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1347 level_pfn = pfn & level_mask(level);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1348
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1349 /* If range covers entire pagetable, free it */
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1350 if (start_pfn <= level_pfn &&
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1351 last_pfn >= level_pfn + level_size(level) - 1) {
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1352 /* These suborbinate page tables are going away entirely. Don't
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1353 bother to clear them; we're just going to *free* them. */
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1354 if (level > 1 && !dma_pte_superpage(pte))
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1355 freelist = dma_pte_list_pagetables(domain, level - 1, pte, freelist);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1356
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1357 dma_clear_pte(pte);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1358 if (!first_pte)
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1359 first_pte = pte;
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1360 last_pte = pte;
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1361 } else if (level > 1) {
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1362 /* Recurse down into a level that isn't *entirely* obsolete */
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1363 freelist = dma_pte_clear_level(domain, level - 1,
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1364 phys_to_virt(dma_pte_addr(pte)),
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1365 level_pfn, start_pfn, last_pfn,
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1366 freelist);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1367 }
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1368 next:
edad96db58d2f0b drivers/iommu/intel/iommu.c Alex Williamson 2021-11-22 1369 pfn = level_pfn + level_size(level);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1370 } while (!first_pte_in_page(++pte) && pfn <= last_pfn);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1371
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1372 if (first_pte)
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1373 domain_flush_cache(domain, first_pte,
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1374 (void *)++last_pte - (void *)first_pte);
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1375
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1376 return freelist;
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1377 }
ea8ea460c9ace60 drivers/iommu/intel-iommu.c David Woodhouse 2014-03-05 1378
:::::: The code at line 1344 was first introduced by commit
:::::: ea8ea460c9ace60bbb5ac6e5521d637d5c15293d iommu/vt-d: Clean up and fix page table clear/free behaviour
:::::: TO: David Woodhouse <David.Woodhouse@intel.com>
:::::: CC: David Woodhouse <David.Woodhouse@intel.com>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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2021-11-26 1:34 [linux-next:master 2984/3632] drivers/iommu/intel/iommu.c:1344:7: warning: variable 'level_pfn' is used uninitialized whenever 'if' condition is true kernel test robot
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