Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "14 patches.

  Subsystems affected by this patch series: mm (hugetlb, kasan, gup,
  selftests, z3fold, kfence, memblock, and highmem), squashfs, ia64,
  gcov, and mailmap"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mailmap: update Andrey Konovalov's email address
  mm/highmem: fix CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP
  mm: memblock: fix section mismatch warning again
  kfence: make compatible with kmemleak
  gcov: fix clang-11+ support
  ia64: fix format strings for err_inject
  ia64: mca: allocate early mca with GFP_ATOMIC
  squashfs: fix xattr id and id lookup sanity checks
  squashfs: fix inode lookup sanity checks
  z3fold: prevent reclaim/free race for headless pages
  selftests/vm: fix out-of-tree build
  mm/mmu_notifiers: ensure range_end() is paired with range_start()
  kasan: fix per-page tags for non-page_alloc pages
  hugetlb_cgroup: fix imbalanced css_get and css_put pair for shared mappings

1 files changed, 37 insertions, 4 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5b1ab1f427c5..a86a58ef132d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -280,6 +280,17 @@ static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
 		nrg->reservation_counter =
 			&h_cg->rsvd_hugepage[hstate_index(h)];
 		nrg->css = &h_cg->css;
+		/*
+		 * The caller will hold exactly one h_cg->css reference for the
+		 * whole contiguous reservation region. But this area might be
+		 * scattered when there are already some file_regions reside in
+		 * it. As a result, many file_regions may share only one css
+		 * reference. In order to ensure that one file_region must hold
+		 * exactly one h_cg->css reference, we should do css_get for
+		 * each file_region and leave the reference held by caller
+		 * untouched.
+		 */
+		css_get(&h_cg->css);
 		if (!resv->pages_per_hpage)
 			resv->pages_per_hpage = pages_per_huge_page(h);
 		/* pages_per_hpage should be the same for all entries in
@@ -293,6 +304,14 @@ static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
 #endif
 }
 
+static void put_uncharge_info(struct file_region *rg)
+{
+#ifdef CONFIG_CGROUP_HUGETLB
+	if (rg->css)
+		css_put(rg->css);
+#endif
+}
+
 static bool has_same_uncharge_info(struct file_region *rg,
 				   struct file_region *org)
 {
@@ -316,6 +335,7 @@ static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
 		prg->to = rg->to;
 
 		list_del(&rg->link);
+		put_uncharge_info(rg);
 		kfree(rg);
 
 		rg = prg;
@@ -327,6 +347,7 @@ static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
 		nrg->from = rg->from;
 
 		list_del(&rg->link);
+		put_uncharge_info(rg);
 		kfree(rg);
 	}
 }
@@ -662,7 +683,7 @@ retry:
 
 			del += t - f;
 			hugetlb_cgroup_uncharge_file_region(
-				resv, rg, t - f);
+				resv, rg, t - f, false);
 
 			/* New entry for end of split region */
 			nrg->from = t;
@@ -683,7 +704,7 @@ retry:
 		if (f <= rg->from && t >= rg->to) { /* Remove entire region */
 			del += rg->to - rg->from;
 			hugetlb_cgroup_uncharge_file_region(resv, rg,
-							    rg->to - rg->from);
+							    rg->to - rg->from, true);
 			list_del(&rg->link);
 			kfree(rg);
 			continue;
@@ -691,13 +712,13 @@ retry:
 
 		if (f <= rg->from) {	/* Trim beginning of region */
 			hugetlb_cgroup_uncharge_file_region(resv, rg,
-							    t - rg->from);
+							    t - rg->from, false);
 
 			del += t - rg->from;
 			rg->from = t;
 		} else {		/* Trim end of region */
 			hugetlb_cgroup_uncharge_file_region(resv, rg,
-							    rg->to - f);
+							    rg->to - f, false);
 
 			del += rg->to - f;
 			rg->to = f;
@@ -5187,6 +5208,10 @@ bool hugetlb_reserve_pages(struct inode *inode,
 			 */
 			long rsv_adjust;
 
+			/*
+			 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
+			 * reference to h_cg->css. See comment below for detail.
+			 */
 			hugetlb_cgroup_uncharge_cgroup_rsvd(
 				hstate_index(h),
 				(chg - add) * pages_per_huge_page(h), h_cg);
@@ -5194,6 +5219,14 @@ bool hugetlb_reserve_pages(struct inode *inode,
 			rsv_adjust = hugepage_subpool_put_pages(spool,
 								chg - add);
 			hugetlb_acct_memory(h, -rsv_adjust);
+		} else if (h_cg) {
+			/*
+			 * The file_regions will hold their own reference to
+			 * h_cg->css. So we should release the reference held
+			 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
+			 * done.
+			 */
+			hugetlb_cgroup_put_rsvd_cgroup(h_cg);
 		}
 	}
 	return true;