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-rw-r--r--fs/proc/task_mmu.c26
1 files changed, 21 insertions, 5 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ef2eb12906da..435b61054b5b 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1982,15 +1982,31 @@ static int pagemap_scan_test_walk(unsigned long start, unsigned long end,
struct pagemap_scan_private *p = walk->private;
struct vm_area_struct *vma = walk->vma;
unsigned long vma_category = 0;
+ bool wp_allowed = userfaultfd_wp_async(vma) &&
+ userfaultfd_wp_use_markers(vma);
- if (userfaultfd_wp_async(vma) && userfaultfd_wp_use_markers(vma))
- vma_category |= PAGE_IS_WPALLOWED;
- else if (p->arg.flags & PM_SCAN_CHECK_WPASYNC)
- return -EPERM;
+ if (!wp_allowed) {
+ /* User requested explicit failure over wp-async capability */
+ if (p->arg.flags & PM_SCAN_CHECK_WPASYNC)
+ return -EPERM;
+ /*
+ * User requires wr-protect, and allows silently skipping
+ * unsupported vmas.
+ */
+ if (p->arg.flags & PM_SCAN_WP_MATCHING)
+ return 1;
+ /*
+ * Then the request doesn't involve wr-protects at all,
+ * fall through to the rest checks, and allow vma walk.
+ */
+ }
if (vma->vm_flags & VM_PFNMAP)
return 1;
+ if (wp_allowed)
+ vma_category |= PAGE_IS_WPALLOWED;
+
if (!pagemap_scan_is_interesting_vma(vma_category, p))
return 1;
@@ -2140,7 +2156,7 @@ static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start,
return 0;
}
- if (!p->vec_out) {
+ if ((p->arg.flags & PM_SCAN_WP_MATCHING) && !p->vec_out) {
/* Fast path for performing exclusive WP */
for (addr = start; addr != end; pte++, addr += PAGE_SIZE) {
if (pte_uffd_wp(ptep_get(pte)))