Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "Rather a lot of fixes, almost all affecting mm/"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (26 commits)
  scripts/gdb: fix debugging modules on s390
  kernel/events/uprobes.c: only do FOLL_SPLIT_PMD for uprobe register
  mm/thp: allow dropping THP from page cache
  mm/vmscan.c: support removing arbitrary sized pages from mapping
  mm/thp: fix node page state in split_huge_page_to_list()
  proc/meminfo: fix output alignment
  mm/init-mm.c: include <linux/mman.h> for vm_committed_as_batch
  mm/filemap.c: include <linux/ramfs.h> for generic_file_vm_ops definition
  mm: include <linux/huge_mm.h> for is_vma_temporary_stack
  zram: fix race between backing_dev_show and backing_dev_store
  mm/memcontrol: update lruvec counters in mem_cgroup_move_account
  ocfs2: fix panic due to ocfs2_wq is null
  hugetlbfs: don't access uninitialized memmaps in pfn_range_valid_gigantic()
  mm: memblock: do not enforce current limit for memblock_phys* family
  mm: memcg: get number of pages on the LRU list in memcgroup base on lru_zone_size
  mm/gup: fix a misnamed "write" argument, and a related bug
  mm/gup_benchmark: add a missing "w" to getopt string
  ocfs2: fix error handling in ocfs2_setattr()
  mm: memcg/slab: fix panic in __free_slab() caused by premature memcg pointer release
  mm/memunmap: don't access uninitialized memmap in memunmap_pages()
  ...

1 files changed, 11 insertions, 2 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 94d38a39d72e..c74761004ee5 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -474,14 +474,17 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	struct vm_area_struct *vma;
 	int ret, is_register, ref_ctr_updated = 0;
 	bool orig_page_huge = false;
+	unsigned int gup_flags = FOLL_FORCE;
 
 	is_register = is_swbp_insn(&opcode);
 	uprobe = container_of(auprobe, struct uprobe, arch);
 
 retry:
+	if (is_register)
+		gup_flags |= FOLL_SPLIT_PMD;
 	/* Read the page with vaddr into memory */
-	ret = get_user_pages_remote(NULL, mm, vaddr, 1,
-			FOLL_FORCE | FOLL_SPLIT_PMD, &old_page, &vma, NULL);
+	ret = get_user_pages_remote(NULL, mm, vaddr, 1, gup_flags,
+				    &old_page, &vma, NULL);
 	if (ret <= 0)
 		return ret;
 
@@ -489,6 +492,12 @@ retry:
 	if (ret <= 0)
 		goto put_old;
 
+	if (WARN(!is_register && PageCompound(old_page),
+		 "uprobe unregister should never work on compound page\n")) {
+		ret = -EINVAL;
+		goto put_old;
+	}
+
 	/* We are going to replace instruction, update ref_ctr. */
 	if (!ref_ctr_updated && uprobe->ref_ctr_offset) {
 		ret = update_ref_ctr(uprobe, mm, is_register ? 1 : -1);