mm: khugepaged: drop commit n/a for v5.2

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

2 files changed, 0 insertions, 98 deletions

diff --git a/queue/khugepaged-retract_page_tables-remember-to-test-exit.patch b/queue/khugepaged-retract_page_tables-remember-to-test-exit.patch
deleted file mode 100644
index 135608e9..00000000
--- a/queue/khugepaged-retract_page_tables-remember-to-test-exit.patch
+++ /dev/null
@@ -1,97 +0,0 @@
-From 18e77600f7a1ed69f8ce46c9e11cad0985712dfa Mon Sep 17 00:00:00 2001
-From: Hugh Dickins <hughd@google.com>
-Date: Thu, 6 Aug 2020 23:26:22 -0700
-Subject: [PATCH] khugepaged: retract_page_tables() remember to test exit
-
-commit 18e77600f7a1ed69f8ce46c9e11cad0985712dfa upstream.
-
-Only once have I seen this scenario (and forgot even to notice what forced
-the eventual crash): a sequence of "BUG: Bad page map" alerts from
-vm_normal_page(), from zap_pte_range() servicing exit_mmap();
-pmd:00000000, pte values corresponding to data in physical page 0.
-
-The pte mappings being zapped in this case were supposed to be from a huge
-page of ext4 text (but could as well have been shmem): my belief is that
-it was racing with collapse_file()'s retract_page_tables(), found *pmd
-pointing to a page table, locked it, but *pmd had become 0 by the time
-start_pte was decided.
-
-In most cases, that possibility is excluded by holding mmap lock; but
-exit_mmap() proceeds without mmap lock.  Most of what's run by khugepaged
-checks khugepaged_test_exit() after acquiring mmap lock:
-khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so,
-for example.  But retract_page_tables() did not: fix that.
-
-The fix is for retract_page_tables() to check khugepaged_test_exit(),
-after acquiring mmap lock, before doing anything to the page table.
-Getting the mmap lock serializes with __mmput(), which briefly takes and
-drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on
-mm_users makes sure we don't touch the page table once exit_mmap() might
-reach it, since exit_mmap() will be proceeding without mmap lock, not
-expecting anyone to be racing with it.
-
-Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages")
-Signed-off-by: Hugh Dickins <hughd@google.com>
-Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
-Cc: Andrea Arcangeli <aarcange@redhat.com>
-Cc: Mike Kravetz <mike.kravetz@oracle.com>
-Cc: Song Liu <songliubraving@fb.com>
-Cc: <stable@vger.kernel.org>	[4.8+]
-Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvils
-Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-
-diff --git a/mm/khugepaged.c b/mm/khugepaged.c
-index a9aca9b71d6f..ac04b332a373 100644
---- a/mm/khugepaged.c
-+++ b/mm/khugepaged.c
-@@ -1532,6 +1532,7 @@ out:
- static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
- {
- 	struct vm_area_struct *vma;
-+	struct mm_struct *mm;
- 	unsigned long addr;
- 	pmd_t *pmd, _pmd;
- 
-@@ -1560,7 +1561,8 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
- 			continue;
- 		if (vma->vm_end < addr + HPAGE_PMD_SIZE)
- 			continue;
--		pmd = mm_find_pmd(vma->vm_mm, addr);
-+		mm = vma->vm_mm;
-+		pmd = mm_find_pmd(mm, addr);
- 		if (!pmd)
- 			continue;
- 		/*
-@@ -1570,17 +1572,19 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
- 		 * mmap_lock while holding page lock. Fault path does it in
- 		 * reverse order. Trylock is a way to avoid deadlock.
- 		 */
--		if (mmap_write_trylock(vma->vm_mm)) {
--			spinlock_t *ptl = pmd_lock(vma->vm_mm, pmd);
--			/* assume page table is clear */
--			_pmd = pmdp_collapse_flush(vma, addr, pmd);
--			spin_unlock(ptl);
--			mmap_write_unlock(vma->vm_mm);
--			mm_dec_nr_ptes(vma->vm_mm);
--			pte_free(vma->vm_mm, pmd_pgtable(_pmd));
-+		if (mmap_write_trylock(mm)) {
-+			if (!khugepaged_test_exit(mm)) {
-+				spinlock_t *ptl = pmd_lock(mm, pmd);
-+				/* assume page table is clear */
-+				_pmd = pmdp_collapse_flush(vma, addr, pmd);
-+				spin_unlock(ptl);
-+				mm_dec_nr_ptes(mm);
-+				pte_free(mm, pmd_pgtable(_pmd));
-+			}
-+			mmap_write_unlock(mm);
- 		} else {
- 			/* Try again later */
--			khugepaged_add_pte_mapped_thp(vma->vm_mm, addr);
-+			khugepaged_add_pte_mapped_thp(mm, addr);
- 		}
- 	}
- 	i_mmap_unlock_write(mapping);
--- 
-2.27.0
-
diff --git a/queue/series b/queue/series
index 30622961..0295e0ed 100644
--- a/queue/series
+++ b/queue/series
@@ -97,7 +97,6 @@ mfd-dln2-Run-event-handler-loop-under-spinlock.patch
 ALSA-echoaudio-Fix-potential-Oops-in-snd_echo_resume.patch
 perf-bench-mem-Always-memset-source-before-memcpy.patch
 sh-landisk-Add-missing-initialization-of-sh_io_port_.patch
-khugepaged-retract_page_tables-remember-to-test-exit.patch
 arm64-dts-marvell-espressobin-add-ethernet-alias.patch
 drm-Added-orientation-quirk-for-ASUS-tablet-model-T1.patch
 drm-fix-drm_dp_mst_port-refcount-leaks-in-drm_dp_mst.patch