mm/pagemap: fix wr-protect even if PM_SCAN_WP_MATCHING not set

The new pagemap ioctl contains a fast path for wr-protections without looking into category masks. It forgets to check PM_SCAN_WP_MATCHING before applying the wr-protections. It can cause, e.g., pte markers installed on archs that do not even support uffd wr-protect. WARNING: CPU: 0 PID: 5059 at mm/memory.c:1520 zap_pte_range mm/memory.c:1520 [inline] Link: https://lkml.kernel.org/r/[email protected] Fixes: 12f6b01 ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag") Signed-off-by: Peter Xu <[email protected]> Reported-by: [email protected] Reviewed-by: David Hildenbrand <[email protected]> Reviewed-by: Andrei Vagin <[email protected]> Cc: Muhammad Usama Anjum <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
sirdarckcat · Dec 7, 2023 · 4980e83 · 4980e83
1 parent 0dff1b4
commit 4980e83
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
@@ -2156,7 +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)))