| Message ID | 20210126044510.2491820-3-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | huge vmalloc mappings | expand |
Hi: On 2021/1/26 12:44, Nicholas Piggin wrote: > apply_to_pte_range might mistake a large pte for bad, or treat it as a > page table, resulting in a crash or corruption. Add a test to warn and > return error if large entries are found. > > Reviewed-by: Christoph Hellwig <hch@lst.de> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > mm/memory.c | 66 +++++++++++++++++++++++++++++++++++++++-------------- > 1 file changed, 49 insertions(+), 17 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index feff48e1465a..672e39a72788 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2440,13 +2440,21 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, > } > do { > next = pmd_addr_end(addr, end); > - if (create || !pmd_none_or_clear_bad(pmd)) { > - err = apply_to_pte_range(mm, pmd, addr, next, fn, data, > - create, mask); > - if (err) > - break; > + if (pmd_none(*pmd) && !create) > + continue; > + if (WARN_ON_ONCE(pmd_leaf(*pmd))) > + return -EINVAL; > + if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { > + if (!create) > + continue; > + pmd_clear_bad(pmd); > } > + err = apply_to_pte_range(mm, pmd, addr, next, > + fn, data, create, mask); > + if (err) > + break; > } while (pmd++, addr = next, addr != end); > + > return err; > } > > @@ -2468,13 +2476,21 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, > } > do { > next = pud_addr_end(addr, end); > - if (create || !pud_none_or_clear_bad(pud)) { > - err = apply_to_pmd_range(mm, pud, addr, next, fn, data, > - create, mask); > - if (err) > - break; > + if (pud_none(*pud) && !create) > + continue; > + if (WARN_ON_ONCE(pud_leaf(*pud))) > + return -EINVAL; > + if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { > + if (!create) > + continue; > + pud_clear_bad(pud); > } > + err = apply_to_pmd_range(mm, pud, addr, next, > + fn, data, create, mask); > + if (err) > + break; > } while (pud++, addr = next, addr != end); > + > return err; > } > > @@ -2496,13 +2512,21 @@ static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, > } > do { > next = p4d_addr_end(addr, end); > - if (create || !p4d_none_or_clear_bad(p4d)) { > - err = apply_to_pud_range(mm, p4d, addr, next, fn, data, > - create, mask); > - if (err) > - break; > + if (p4d_none(*p4d) && !create) > + continue; > + if (WARN_ON_ONCE(p4d_leaf(*p4d))) > + return -EINVAL; > + if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { > + if (!create) > + continue; > + p4d_clear_bad(p4d); > } > + err = apply_to_pud_range(mm, p4d, addr, next, > + fn, data, create, mask); > + if (err) > + break; > } while (p4d++, addr = next, addr != end); > + > return err; > } > > @@ -2522,9 +2546,17 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, > pgd = pgd_offset(mm, addr); > do { > next = pgd_addr_end(addr, end); > - if (!create && pgd_none_or_clear_bad(pgd)) > + if (pgd_none(*pgd) && !create) > continue; > - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask); > + if (WARN_ON_ONCE(pgd_leaf(*pgd))) > + return -EINVAL; > + if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { > + if (!create) > + continue; > + pgd_clear_bad(pgd); > + } > + err = apply_to_p4d_range(mm, pgd, addr, next, > + fn, data, create, &mask); > if (err) > break; > } while (pgd++, addr = next, addr != end); > Looks good to me, thanks. Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
diff --git a/mm/memory.c b/mm/memory.c index feff48e1465a..672e39a72788 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2440,13 +2440,21 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, } do { next = pmd_addr_end(addr, end); - if (create || !pmd_none_or_clear_bad(pmd)) { - err = apply_to_pte_range(mm, pmd, addr, next, fn, data, - create, mask); - if (err) - break; + if (pmd_none(*pmd) && !create) + continue; + if (WARN_ON_ONCE(pmd_leaf(*pmd))) + return -EINVAL; + if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { + if (!create) + continue; + pmd_clear_bad(pmd); } + err = apply_to_pte_range(mm, pmd, addr, next, + fn, data, create, mask); + if (err) + break; } while (pmd++, addr = next, addr != end); + return err; } @@ -2468,13 +2476,21 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, } do { next = pud_addr_end(addr, end); - if (create || !pud_none_or_clear_bad(pud)) { - err = apply_to_pmd_range(mm, pud, addr, next, fn, data, - create, mask); - if (err) - break; + if (pud_none(*pud) && !create) + continue; + if (WARN_ON_ONCE(pud_leaf(*pud))) + return -EINVAL; + if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { + if (!create) + continue; + pud_clear_bad(pud); } + err = apply_to_pmd_range(mm, pud, addr, next, + fn, data, create, mask); + if (err) + break; } while (pud++, addr = next, addr != end); + return err; } @@ -2496,13 +2512,21 @@ static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, } do { next = p4d_addr_end(addr, end); - if (create || !p4d_none_or_clear_bad(p4d)) { - err = apply_to_pud_range(mm, p4d, addr, next, fn, data, - create, mask); - if (err) - break; + if (p4d_none(*p4d) && !create) + continue; + if (WARN_ON_ONCE(p4d_leaf(*p4d))) + return -EINVAL; + if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { + if (!create) + continue; + p4d_clear_bad(p4d); } + err = apply_to_pud_range(mm, p4d, addr, next, + fn, data, create, mask); + if (err) + break; } while (p4d++, addr = next, addr != end); + return err; } @@ -2522,9 +2546,17 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, pgd = pgd_offset(mm, addr); do { next = pgd_addr_end(addr, end); - if (!create && pgd_none_or_clear_bad(pgd)) + if (pgd_none(*pgd) && !create) continue; - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask); + if (WARN_ON_ONCE(pgd_leaf(*pgd))) + return -EINVAL; + if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { + if (!create) + continue; + pgd_clear_bad(pgd); + } + err = apply_to_p4d_range(mm, pgd, addr, next, + fn, data, create, &mask); if (err) break; } while (pgd++, addr = next, addr != end);