* [linux-next:master 5970/6564] mm/huge_memory.c:2145:4: warning: Value stored to 'page' is never read [clang-analyzer-deadcode.DeadStores]
[not found] <202202220917.CFUvfxmY-lkp@intel.com>
@ 2022-02-22 9:05 ` kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2022-02-22 9:05 UTC (permalink / raw)
To: Hugh Dickins
Cc: llvm, kbuild-all, Linux Memory Management List, Andrew Morton,
Linux Memory Management List
tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head: 3c30cf91b5ecc7272b3d2942ae0505dd8320b81c
commit: c1879365d325d0f44337fedcfffe8bf200092f95 [5970/6564] mm/munlock: rmap call mlock_vma_page() munlock_vma_page()
config: x86_64-randconfig-c007-20220221 (https://download.01.org/0day-ci/archive/20220222/202202220917.CFUvfxmY-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
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=c1879365d325d0f44337fedcfffe8bf200092f95
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 c1879365d325d0f44337fedcfffe8bf200092f95
# save the config file to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 clang-analyzer
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <yujie.liu@intel.com>
clang-analyzer warnings: (new ones prefixed by >>)
>> mm/huge_memory.c:2145:4: warning: Value stored to 'page' is never read [clang-analyzer-deadcode.DeadStores]
page = pmd_page(*pmd);
^
vim +/page +2145 mm/huge_memory.c
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2119
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2120 void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
33f4751e99601b Naoya Horiguchi 2016-07-14 2121 unsigned long address, bool freeze, struct page *page)
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2122 {
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2123 spinlock_t *ptl;
ac46d4f3c43241 Jérôme Glisse 2018-12-28 2124 struct mmu_notifier_range range;
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2125
7269f999934b28 Jérôme Glisse 2019-05-13 2126 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
6f4f13e8d9e27c Jérôme Glisse 2019-05-13 2127 address & HPAGE_PMD_MASK,
ac46d4f3c43241 Jérôme Glisse 2018-12-28 2128 (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE);
ac46d4f3c43241 Jérôme Glisse 2018-12-28 2129 mmu_notifier_invalidate_range_start(&range);
ac46d4f3c43241 Jérôme Glisse 2018-12-28 2130 ptl = pmd_lock(vma->vm_mm, pmd);
33f4751e99601b Naoya Horiguchi 2016-07-14 2131
33f4751e99601b Naoya Horiguchi 2016-07-14 2132 /*
33f4751e99601b Naoya Horiguchi 2016-07-14 2133 * If caller asks to setup a migration entries, we need a page to check
33f4751e99601b Naoya Horiguchi 2016-07-14 2134 * pmd against. Otherwise we can end up replacing wrong page.
33f4751e99601b Naoya Horiguchi 2016-07-14 2135 */
33f4751e99601b Naoya Horiguchi 2016-07-14 2136 VM_BUG_ON(freeze && !page);
c444eb564fb166 Andrea Arcangeli 2020-05-27 2137 if (page) {
c444eb564fb166 Andrea Arcangeli 2020-05-27 2138 VM_WARN_ON_ONCE(!PageLocked(page));
c444eb564fb166 Andrea Arcangeli 2020-05-27 2139 if (page != pmd_page(*pmd))
33f4751e99601b Naoya Horiguchi 2016-07-14 2140 goto out;
c444eb564fb166 Andrea Arcangeli 2020-05-27 2141 }
33f4751e99601b Naoya Horiguchi 2016-07-14 2142
5c7fb56e5e3f70 Dan Williams 2016-01-15 2143 if (pmd_trans_huge(*pmd)) {
dbe67be3d9f30a David Hildenbrand 2022-02-16 2144 if (!page)
33f4751e99601b Naoya Horiguchi 2016-07-14 @2145 page = pmd_page(*pmd);
84c3fc4e9c563d Zi Yan 2017-09-08 2146 } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd)))
5c7fb56e5e3f70 Dan Williams 2016-01-15 2147 goto out;
ac46d4f3c43241 Jérôme Glisse 2018-12-28 2148 __split_huge_pmd_locked(vma, pmd, range.start, freeze);
e90309c9f7722d Kirill A. Shutemov 2016-01-15 2149 out:
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2150 spin_unlock(ptl);
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2151 /*
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2152 * No need to double call mmu_notifier->invalidate_range() callback.
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2153 * They are 3 cases to consider inside __split_huge_pmd_locked():
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2154 * 1) pmdp_huge_clear_flush_notify() call invalidate_range() obvious
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2155 * 2) __split_huge_zero_page_pmd() read only zero page and any write
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2156 * fault will trigger a flush_notify before pointing to a new page
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2157 * (it is fine if the secondary mmu keeps pointing to the old zero
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2158 * page in the meantime)
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2159 * 3) Split a huge pmd into pte pointing to the same page. No need
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2160 * to invalidate secondary tlb entry they are all still valid.
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2161 * any further changes to individual pte will notify. So no need
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2162 * to call mmu_notifier->invalidate_range()
4645b9fe84bf48 Jérôme Glisse 2017-11-15 2163 */
ac46d4f3c43241 Jérôme Glisse 2018-12-28 2164 mmu_notifier_invalidate_range_only_end(&range);
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2165 }
eef1b3ba053aa6 Kirill A. Shutemov 2016-01-15 2166
---
0-DAY CI Kernel Test Service, Intel Corporation
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