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Message-ID: <202202241452.QrPElUkk-lkp@intel.com>
Date: Thu, 24 Feb 2022 18:19:04 +0300
From: Dan Carpenter <dan.carpenter@...cle.com>
To: kbuild@...ts.01.org, David Hildenbrand <david@...hat.com>
Cc: lkp@...el.com, kbuild-all@...ts.01.org,
linux-kernel@...r.kernel.org,
Andrea Arcangeli <aarcange@...hat.com>
Subject: [davidhildenbrand:cow_fixes_part_2 21/27] mm/hugetlb.c:6051
follow_hugetlb_page() error: uninitialized symbol 'unshare'.
tree: git://github.com/davidhildenbrand/linux cow_fixes_part_2
head: 6a519d5bcfc204824056f340a0cfc86207962151
commit: d41af2eea859d0123cf08a88eae48239d5bdae2b [21/27] mm/gup: trigger FAULT_FLAG_UNSHARE when R/O-pinning a possibly shared anonymous page
config: x86_64-randconfig-m001 (https://download.01.org/0day-ci/archive/20220224/202202241452.QrPElUkk-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
smatch warnings:
mm/hugetlb.c:6051 follow_hugetlb_page() error: uninitialized symbol 'unshare'.
vim +/unshare +6051 mm/hugetlb.c
28a35716d31798 Michel Lespinasse 2013-02-22 5977 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
63551ae0feaaa2 David Gibson 2005-06-21 5978 struct page **pages, struct vm_area_struct **vmas,
28a35716d31798 Michel Lespinasse 2013-02-22 5979 unsigned long *position, unsigned long *nr_pages,
4f6da93411806d Peter Xu 2020-04-01 5980 long i, unsigned int flags, int *locked)
63551ae0feaaa2 David Gibson 2005-06-21 5981 {
d5d4b0aa4e1430 Kenneth W Chen 2006-03-22 5982 unsigned long pfn_offset;
d5d4b0aa4e1430 Kenneth W Chen 2006-03-22 5983 unsigned long vaddr = *position;
28a35716d31798 Michel Lespinasse 2013-02-22 5984 unsigned long remainder = *nr_pages;
a5516438959d90 Andi Kleen 2008-07-23 5985 struct hstate *h = hstate_vma(vma);
0fa5bc4023c188 Joao Martins 2021-02-24 5986 int err = -EFAULT, refs;
63551ae0feaaa2 David Gibson 2005-06-21 5987
63551ae0feaaa2 David Gibson 2005-06-21 5988 while (vaddr < vma->vm_end && remainder) {
63551ae0feaaa2 David Gibson 2005-06-21 5989 pte_t *pte;
cb900f41215447 Kirill A. Shutemov 2013-11-14 5990 spinlock_t *ptl = NULL;
d41af2eea859d0 David Hildenbrand 2021-12-16 5991 bool unshare;
2a15efc953b26a Hugh Dickins 2009-09-21 5992 int absent;
63551ae0feaaa2 David Gibson 2005-06-21 5993 struct page *page;
63551ae0feaaa2 David Gibson 2005-06-21 5994
02057967b5d3b7 David Rientjes 2015-04-14 5995 /*
02057967b5d3b7 David Rientjes 2015-04-14 5996 * If we have a pending SIGKILL, don't keep faulting pages and
02057967b5d3b7 David Rientjes 2015-04-14 5997 * potentially allocating memory.
02057967b5d3b7 David Rientjes 2015-04-14 5998 */
fa45f1162f28cb Davidlohr Bueso 2019-01-03 5999 if (fatal_signal_pending(current)) {
02057967b5d3b7 David Rientjes 2015-04-14 6000 remainder = 0;
02057967b5d3b7 David Rientjes 2015-04-14 6001 break;
02057967b5d3b7 David Rientjes 2015-04-14 6002 }
02057967b5d3b7 David Rientjes 2015-04-14 6003
4c887265977213 Adam Litke 2005-10-29 6004 /*
4c887265977213 Adam Litke 2005-10-29 6005 * Some archs (sparc64, sh*) have multiple pte_ts to
2a15efc953b26a Hugh Dickins 2009-09-21 6006 * each hugepage. We have to make sure we get the
4c887265977213 Adam Litke 2005-10-29 6007 * first, for the page indexing below to work.
cb900f41215447 Kirill A. Shutemov 2013-11-14 6008 *
cb900f41215447 Kirill A. Shutemov 2013-11-14 6009 * Note that page table lock is not held when pte is null.
4c887265977213 Adam Litke 2005-10-29 6010 */
7868a2087ec13e Punit Agrawal 2017-07-06 6011 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
7868a2087ec13e Punit Agrawal 2017-07-06 6012 huge_page_size(h));
cb900f41215447 Kirill A. Shutemov 2013-11-14 6013 if (pte)
cb900f41215447 Kirill A. Shutemov 2013-11-14 6014 ptl = huge_pte_lock(h, mm, pte);
2a15efc953b26a Hugh Dickins 2009-09-21 6015 absent = !pte || huge_pte_none(huge_ptep_get(pte));
2a15efc953b26a Hugh Dickins 2009-09-21 6016
2a15efc953b26a Hugh Dickins 2009-09-21 6017 /*
2a15efc953b26a Hugh Dickins 2009-09-21 6018 * When coredumping, it suits get_dump_page if we just return
3ae77f43b1118a Hugh Dickins 2009-09-21 6019 * an error where there's an empty slot with no huge pagecache
3ae77f43b1118a Hugh Dickins 2009-09-21 6020 * to back it. This way, we avoid allocating a hugepage, and
3ae77f43b1118a Hugh Dickins 2009-09-21 6021 * the sparse dumpfile avoids allocating disk blocks, but its
3ae77f43b1118a Hugh Dickins 2009-09-21 6022 * huge holes still show up with zeroes where they need to be.
2a15efc953b26a Hugh Dickins 2009-09-21 6023 */
3ae77f43b1118a Hugh Dickins 2009-09-21 6024 if (absent && (flags & FOLL_DUMP) &&
3ae77f43b1118a Hugh Dickins 2009-09-21 6025 !hugetlbfs_pagecache_present(h, vma, vaddr)) {
cb900f41215447 Kirill A. Shutemov 2013-11-14 6026 if (pte)
cb900f41215447 Kirill A. Shutemov 2013-11-14 6027 spin_unlock(ptl);
2a15efc953b26a Hugh Dickins 2009-09-21 6028 remainder = 0;
2a15efc953b26a Hugh Dickins 2009-09-21 6029 break;
2a15efc953b26a Hugh Dickins 2009-09-21 6030 }
63551ae0feaaa2 David Gibson 2005-06-21 6031
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6032 /*
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6033 * We need call hugetlb_fault for both hugepages under migration
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6034 * (in which case hugetlb_fault waits for the migration,) and
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6035 * hwpoisoned hugepages (in which case we need to prevent the
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6036 * caller from accessing to them.) In order to do this, we use
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6037 * here is_swap_pte instead of is_hugetlb_entry_migration and
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6038 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6039 * both cases, and because we can't follow correct pages
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6040 * directly from any kind of swap entries.
9cc3a5bd40067b Naoya Horiguchi 2013-04-17 6041 */
d41af2eea859d0 David Hildenbrand 2021-12-16 6042 if (absent ||
d41af2eea859d0 David Hildenbrand 2021-12-16 6043 __follow_hugetlb_must_fault(flags, pte, &unshare)) {
Can absent be true
2b7403035459c7 Souptick Joarder 2018-08-23 6044 vm_fault_t ret;
87ffc118b54dcd Andrea Arcangeli 2017-02-22 6045 unsigned int fault_flags = 0;
4c887265977213 Adam Litke 2005-10-29 6046
cb900f41215447 Kirill A. Shutemov 2013-11-14 6047 if (pte)
cb900f41215447 Kirill A. Shutemov 2013-11-14 6048 spin_unlock(ptl);
87ffc118b54dcd Andrea Arcangeli 2017-02-22 6049 if (flags & FOLL_WRITE)
87ffc118b54dcd Andrea Arcangeli 2017-02-22 6050 fault_flags |= FAULT_FLAG_WRITE;
And FOLL_WRITE is not set?
d41af2eea859d0 David Hildenbrand 2021-12-16 @6051 else if (unshare)
^^^^^^^
Uninitialized warning...
d41af2eea859d0 David Hildenbrand 2021-12-16 6052 fault_flags |= FAULT_FLAG_UNSHARE;
4f6da93411806d Peter Xu 2020-04-01 6053 if (locked)
71335f37c5e8ec Peter Xu 2020-04-01 6054 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
71335f37c5e8ec Peter Xu 2020-04-01 6055 FAULT_FLAG_KILLABLE;
87ffc118b54dcd Andrea Arcangeli 2017-02-22 6056 if (flags & FOLL_NOWAIT)
87ffc118b54dcd Andrea Arcangeli 2017-02-22 6057 fault_flags |= FAULT_FLAG_ALLOW_RETRY |
87ffc118b54dcd Andrea Arcangeli 2017-02-22 6058 FAULT_FLAG_RETRY_NOWAIT;
87ffc118b54dcd Andrea Arcangeli 2017-02-22 6059 if (flags & FOLL_TRIED) {
4426e945df588f Peter Xu 2020-04-01 6060 /*
4426e945df588f Peter Xu 2020-04-01 6061 * Note: FAULT_FLAG_ALLOW_RETRY and
---
0-DAY CI Kernel Test Service, Intel Corporation
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