Merge tag 'mm-hotfixes-stable-2023-04-19-16-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "22 hotfixes.

  19 are cc:stable and the remainder address issues which were
  introduced during this merge cycle, or aren't considered suitable for
  -stable backporting.

  19 are for MM and the remainder are for other subsystems"

* tag 'mm-hotfixes-stable-2023-04-19-16-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
  nilfs2: initialize unused bytes in segment summary blocks
  mm: page_alloc: skip regions with hugetlbfs pages when allocating 1G pages
  mm/mmap: regression fix for unmapped_area{_topdown}
  maple_tree: fix mas_empty_area() search
  maple_tree: make maple state reusable after mas_empty_area_rev()
  mm: kmsan: handle alloc failures in kmsan_ioremap_page_range()
  mm: kmsan: handle alloc failures in kmsan_vmap_pages_range_noflush()
  tools/Makefile: do missed s/vm/mm/
  mm: fix memory leak on mm_init error handling
  mm/page_alloc: fix potential deadlock on zonelist_update_seq seqlock
  kernel/sys.c: fix and improve control flow in __sys_setres[ug]id()
  Revert "userfaultfd: don't fail on unrecognized features"
  writeback, cgroup: fix null-ptr-deref write in bdi_split_work_to_wbs
  maple_tree: fix a potential memory leak, OOB access, or other unpredictable bug
  tools/mm/page_owner_sort.c: fix TGID output when cull=tg is used
  mailmap: update jtoppins' entry to reference correct email
  mm/mempolicy: fix use-after-free of VMA iterator
  mm/huge_memory.c: warn with pr_warn_ratelimited instead of VM_WARN_ON_ONCE_FOLIO
  mm/mprotect: fix do_mprotect_pkey() return on error
  mm/khugepaged: check again on anon uffd-wp during isolation
  ...

3 files changed, 34 insertions, 9 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 195dc23e0d83..1db3e3c24b43 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -978,6 +978,16 @@ restart:
 			continue;
 		}
 
+		/*
+		 * If wb_tryget fails, the wb has been shutdown, skip it.
+		 *
+		 * Pin @wb so that it stays on @bdi->wb_list.  This allows
+		 * continuing iteration from @wb after dropping and
+		 * regrabbing rcu read lock.
+		 */
+		if (!wb_tryget(wb))
+			continue;
+
 		/* alloc failed, execute synchronously using on-stack fallback */
 		work = &fallback_work;
 		*work = *base_work;
@@ -986,13 +996,6 @@ restart:
 		work->done = &fallback_work_done;
 
 		wb_queue_work(wb, work);
-
-		/*
-		 * Pin @wb so that it stays on @bdi->wb_list.  This allows
-		 * continuing iteration from @wb after dropping and
-		 * regrabbing rcu read lock.
-		 */
-		wb_get(wb);
 		last_wb = wb;
 
 		rcu_read_unlock();
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 6ad41390fa74..228659612c0d 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -430,6 +430,23 @@ static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
 	return 0;
 }
 
+/**
+ * nilfs_segctor_zeropad_segsum - zero pad the rest of the segment summary area
+ * @sci: segment constructor object
+ *
+ * nilfs_segctor_zeropad_segsum() zero-fills unallocated space at the end of
+ * the current segment summary block.
+ */
+static void nilfs_segctor_zeropad_segsum(struct nilfs_sc_info *sci)
+{
+	struct nilfs_segsum_pointer *ssp;
+
+	ssp = sci->sc_blk_cnt > 0 ? &sci->sc_binfo_ptr : &sci->sc_finfo_ptr;
+	if (ssp->offset < ssp->bh->b_size)
+		memset(ssp->bh->b_data + ssp->offset, 0,
+		       ssp->bh->b_size - ssp->offset);
+}
+
 static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 {
 	sci->sc_nblk_this_inc += sci->sc_curseg->sb_sum.nblocks;
@@ -438,6 +455,7 @@ static int nilfs_segctor_feed_segment(struct nilfs_sc_info *sci)
 				* The current segment is filled up
 				* (internal code)
 				*/
+	nilfs_segctor_zeropad_segsum(sci);
 	sci->sc_curseg = NILFS_NEXT_SEGBUF(sci->sc_curseg);
 	return nilfs_segctor_reset_segment_buffer(sci);
 }
@@ -542,6 +560,7 @@ static int nilfs_segctor_add_file_block(struct nilfs_sc_info *sci,
 		goto retry;
 	}
 	if (unlikely(required)) {
+		nilfs_segctor_zeropad_segsum(sci);
 		err = nilfs_segbuf_extend_segsum(segbuf);
 		if (unlikely(err))
 			goto failed;
@@ -1533,6 +1552,7 @@ static int nilfs_segctor_collect(struct nilfs_sc_info *sci,
 		nadd = min_t(int, nadd << 1, SC_MAX_SEGDELTA);
 		sci->sc_stage = prev_stage;
 	}
+	nilfs_segctor_zeropad_segsum(sci);
 	nilfs_segctor_truncate_segments(sci, sci->sc_curseg, nilfs->ns_sufile);
 	return 0;
 
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 44d1ee429eb0..40f9e1a2ebdd 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1955,8 +1955,10 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
 	ret = -EFAULT;
 	if (copy_from_user(&uffdio_api, buf, sizeof(uffdio_api)))
 		goto out;
-	/* Ignore unsupported features (userspace built against newer kernel) */
-	features = uffdio_api.features & UFFD_API_FEATURES;
+	features = uffdio_api.features;
+	ret = -EINVAL;
+	if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES))
+		goto err_out;
 	ret = -EPERM;
 	if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE))
 		goto err_out;