Merge tag 'mm-hotfixes-stable-2024-10-28-21-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "21 hotfixes. 13 are cc:stable. 13 are MM and 8 are non-MM.

  No particular theme here - mainly singletons, a couple of doubletons.
  Please see the changelogs"

* tag 'mm-hotfixes-stable-2024-10-28-21-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (21 commits)
  mm: avoid unconditional one-tick sleep when swapcache_prepare fails
  mseal: update mseal.rst
  mm: split critical region in remap_file_pages() and invoke LSMs in between
  selftests/mm: fix deadlock for fork after pthread_create with atomic_bool
  Revert "selftests/mm: replace atomic_bool with pthread_barrier_t"
  Revert "selftests/mm: fix deadlock for fork after pthread_create on ARM"
  tools: testing: add expand-only mode VMA test
  mm/vma: add expand-only VMA merge mode and optimise do_brk_flags()
  resource,kexec: walk_system_ram_res_rev must retain resource flags
  nilfs2: fix kernel bug due to missing clearing of checked flag
  mm: numa_clear_kernel_node_hotplug: Add NUMA_NO_NODE check for node id
  ocfs2: pass u64 to ocfs2_truncate_inline maybe overflow
  mm: shmem: fix data-race in shmem_getattr()
  mm: mark mas allocation in vms_abort_munmap_vmas as __GFP_NOFAIL
  x86/traps: move kmsan check after instrumentation_begin
  resource: remove dependency on SPARSEMEM from GET_FREE_REGION
  mm/mmap: fix race in mmap_region() with ftruncate()
  mm/page_alloc: let GFP_ATOMIC order-0 allocs access highatomic reserves
  fork: only invoke khugepaged, ksm hooks if no error
  fork: do not invoke uffd on fork if error occurs
  ...

1 files changed, 6 insertions, 6 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 89ceb4a68af2..3bf38d260cb3 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -653,11 +653,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 	mm->exec_vm = oldmm->exec_vm;
 	mm->stack_vm = oldmm->stack_vm;
 
-	retval = ksm_fork(mm, oldmm);
-	if (retval)
-		goto out;
-	khugepaged_fork(mm, oldmm);
-
 	/* Use __mt_dup() to efficiently build an identical maple tree. */
 	retval = __mt_dup(&oldmm->mm_mt, &mm->mm_mt, GFP_KERNEL);
 	if (unlikely(retval))
@@ -760,6 +755,8 @@ loop_out:
 	vma_iter_free(&vmi);
 	if (!retval) {
 		mt_set_in_rcu(vmi.mas.tree);
+		ksm_fork(mm, oldmm);
+		khugepaged_fork(mm, oldmm);
 	} else if (mpnt) {
 		/*
 		 * The entire maple tree has already been duplicated. If the
@@ -775,7 +772,10 @@ out:
 	mmap_write_unlock(mm);
 	flush_tlb_mm(oldmm);
 	mmap_write_unlock(oldmm);
-	dup_userfaultfd_complete(&uf);
+	if (!retval)
+		dup_userfaultfd_complete(&uf);
+	else
+		dup_userfaultfd_fail(&uf);
 fail_uprobe_end:
 	uprobe_end_dup_mmap();
 	return retval;