kfence: test: fail fast if disabled at boot

[linux-2.6-microblaze.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dfc940d..8ea35ba 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2476,7 +2476,7 @@ void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
                if (!rc) {
                        /*
                         * This indicates there is an entry in the reserve map
-                        * added by alloc_huge_page.  We know it was added
+                        * not added by alloc_huge_page.  We know it was added
                         * before the alloc_huge_page call, otherwise
                         * HPageRestoreReserve would be set on the page.
                         * Remove the entry so that a subsequent allocation
@@ -4660,7 +4660,9 @@ retry_avoidcopy:
        spin_unlock(ptl);
        mmu_notifier_invalidate_range_end(&range);
 out_release_all:
-       restore_reserve_on_error(h, vma, haddr, new_page);
+       /* No restore in case of successful pagetable update (Break COW) */
+       if (new_page != old_page)
+               restore_reserve_on_error(h, vma, haddr, new_page);
        put_page(new_page);
 out_release_old:
        put_page(old_page);
@@ -4776,7 +4778,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
        pte_t new_pte;
        spinlock_t *ptl;
        unsigned long haddr = address & huge_page_mask(h);
-       bool new_page = false;
+       bool new_page, new_pagecache_page = false;
 
        /*
         * Currently, we are forced to kill the process in the event the
@@ -4799,6 +4801,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
                goto out;
 
 retry:
+       new_page = false;
        page = find_lock_page(mapping, idx);
        if (!page) {
                /* Check for page in userfault range */
@@ -4842,6 +4845,7 @@ retry:
                                        goto retry;
                                goto out;
                        }
+                       new_pagecache_page = true;
                } else {
                        lock_page(page);
                        if (unlikely(anon_vma_prepare(vma))) {
@@ -4926,7 +4930,9 @@ backout:
        spin_unlock(ptl);
 backout_unlocked:
        unlock_page(page);
-       restore_reserve_on_error(h, vma, haddr, page);
+       /* restore reserve for newly allocated pages not in page cache */
+       if (new_page && !new_pagecache_page)
+               restore_reserve_on_error(h, vma, haddr, page);
        put_page(page);
        goto out;
 }
@@ -5135,6 +5141,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
        int ret = -ENOMEM;
        struct page *page;
        int writable;
+       bool new_pagecache_page = false;
 
        if (is_continue) {
                ret = -EFAULT;
@@ -5228,6 +5235,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
                ret = huge_add_to_page_cache(page, mapping, idx);
                if (ret)
                        goto out_release_nounlock;
+               new_pagecache_page = true;
        }
 
        ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
@@ -5291,7 +5299,8 @@ out_release_unlock:
        if (vm_shared || is_continue)
                unlock_page(page);
 out_release_nounlock:
-       restore_reserve_on_error(h, dst_vma, dst_addr, page);
+       if (!new_pagecache_page)
+               restore_reserve_on_error(h, dst_vma, dst_addr, page);
        put_page(page);
        goto out;
 }