From 4980e837cab7e2acc4dad18dba656c6896c531aa Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Thu, 16 Nov 2023 15:15:46 -0500 Subject: 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/20231116201547.536857-3-peterx@redhat.com Fixes: 12f6b01a0bcb ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag") Signed-off-by: Peter Xu Reported-by: syzbot+7ca4b2719dc742b8d0a4@syzkaller.appspotmail.com Reviewed-by: David Hildenbrand Reviewed-by: Andrei Vagin Cc: Muhammad Usama Anjum Signed-off-by: Andrew Morton --- fs/proc/task_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index a6f88cbfb689..435b61054b5b 100644 --- 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))) -- cgit v1.2.3