[patch 007/173] ntfs: check for valid standard information attribute

[patch 007/173] ntfs: check for valid standard information attribute

[Andrew Morton]

From: Rustam Kovhaev <rkovhaev@gmail.com>
Subject: ntfs: check for valid standard information attribute

Mounting a corrupted filesystem with NTFS resulted in a kernel crash.

We should check for valid STANDARD_INFORMATION attribute offset and length
before trying to access it

Link: https://lkml.kernel.org/r/20210217155930.1506815-1-rkovhaev@gmail.com
Link: https://syzkaller.appspot.com/bug?extid=c584225dabdea2f71969
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Reported-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Tested-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ntfs/inode.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/fs/ntfs/inode.c~ntfs-check-for-valid-standard-information-attribute
+++ a/fs/ntfs/inode.c
@@ -629,6 +629,12 @@ static int ntfs_read_locked_inode(struct
 	}
 	a = ctx->attr;
 	/* Get the standard information attribute value. */
+	if ((u8 *)a + le16_to_cpu(a->data.resident.value_offset)
+			+ le32_to_cpu(a->data.resident.value_length) >
+			(u8 *)ctx->mrec + vol->mft_record_size) {
+		ntfs_error(vi->i_sb, "Corrupt standard information attribute in inode.");
+		goto unm_err_out;
+	}
 	si = (STANDARD_INFORMATION*)((u8*)a +
 			le16_to_cpu(a->data.resident.value_offset));
 
_

[patch 073/173] mm: memcontrol: fix swap undercounting in cgroup2

[Andrew Morton]

From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: memcontrol: fix swap undercounting in cgroup2

When pages are swapped in, the VM may retain the swap copy to avoid
repeated writes in the future.  It's also retained if shared pages are
faulted back in some processes, but not in others.  During that time we
have an in-memory copy of the page, as well as an on-swap copy.  Cgroup1
and cgroup2 handle these overlapping lifetimes slightly differently due to
the nature of how they account memory and swap:

Cgroup1 has a unified memory+swap counter that tracks a data page
regardless whether it's in-core or swapped out.  On swapin, we transfer
the charge from the swap entry to the newly allocated swapcache page, even
though the swap entry might stick around for a while.  That's why we have
a mem_cgroup_uncharge_swap() call inside mem_cgroup_charge().

Cgroup2 tracks memory and swap as separate, independent resources and thus
has split memory and swap counters.  On swapin, we charge the newly
allocated swapcache page as memory, while the swap slot in turn must
remain charged to the swap counter as long as its allocated too.

The cgroup2 logic was broken by commit 2d1c498072de ("mm: memcontrol: make
swap tracking an integral part of memory control"), because it
accidentally removed the do_memsw_account() check in the branch inside
mem_cgroup_uncharge() that was supposed to tell the difference between the
charge transfer in cgroup1 and the separate counters in cgroup2.

As a result, cgroup2 currently undercounts retained swap to varying
degrees: swap slots are cached up to 50% of the configured limit or total
available swap space; partially faulted back shared pages are only limited
by physical capacity.  This in turn allows cgroups to significantly
overconsume their alloted swap space.

Add the do_memsw_account() check back to fix this problem.

Link: https://lkml.kernel.org/r/20210217153237.92484-1-songmuchun@bytedance.com
Fixes: 2d1c498072de ("mm: memcontrol: make swap tracking an integral part of memory control")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>	[5.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memcontrol.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

--- a/mm/memcontrol.c~mm-memcontrol-fix-swap-undercounting-in-cgroup2
+++ a/mm/memcontrol.c
@@ -6748,7 +6748,19 @@ int mem_cgroup_charge(struct page *page,
 	memcg_check_events(memcg, page);
 	local_irq_enable();
 
-	if (PageSwapCache(page)) {
+	/*
+	 * Cgroup1's unified memory+swap counter has been charged with the
+	 * new swapcache page, finish the transfer by uncharging the swap
+	 * slot. The swap slot would also get uncharged when it dies, but
+	 * it can stick around indefinitely and we'd count the page twice
+	 * the entire time.
+	 *
+	 * Cgroup2 has separate resource counters for memory and swap,
+	 * so this is a non-issue here. Memory and swap charge lifetimes
+	 * correspond 1:1 to page and swap slot lifetimes: we charge the
+	 * page to memory here, and uncharge swap when the slot is freed.
+	 */
+	if (do_memsw_account() && PageSwapCache(page)) {
 		swp_entry_t entry = { .val = page_private(page) };
 		/*
 		 * The swap entry might not get freed for a long time,
_

[patch 074/173] mm: memcontrol: fix get_active_memcg return value

[Andrew Morton]

From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: memcontrol: fix get_active_memcg return value

We use a global percpu int_active_memcg variable to store the remote memcg
when we are in the interrupt context.  But get_active_memcg always return
the current->active_memcg or root_mem_cgroup.  The remote memcg (set in
the interrupt context) is ignored.  This is not what we want.  So fix it.

Link: https://lkml.kernel.org/r/20210223091101.42150-1-songmuchun@bytedance.com
Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memcontrol.c |   10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

--- a/mm/memcontrol.c~mm-memcontrol-fix-get_active_memcg-return-value
+++ a/mm/memcontrol.c
@@ -1061,13 +1061,9 @@ static __always_inline struct mem_cgroup
 
 	rcu_read_lock();
 	memcg = active_memcg();
-	if (memcg) {
-		/* current->active_memcg must hold a ref. */
-		if (WARN_ON_ONCE(!css_tryget(&memcg->css)))
-			memcg = root_mem_cgroup;
-		else
-			memcg = current->active_memcg;
-	}
+	/* remote memcg must hold a ref. */
+	if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css)))
+		memcg = root_mem_cgroup;
 	rcu_read_unlock();
 
 	return memcg;
_

[patch 130/173] hugetlb: fix update_and_free_page contig page struct assumption

[Andrew Morton]

From: Mike Kravetz <mike.kravetz@oracle.com>
Subject: hugetlb: fix update_and_free_page contig page struct assumption

page structs are not guaranteed to be contiguous for gigantic pages.  The
routine update_and_free_page can encounter a gigantic page, yet it assumes
page structs are contiguous when setting page flags in subpages.

If update_and_free_page encounters non-contiguous page structs, we can see
“BUG: Bad page state in process …” errors.

Non-contiguous page structs are generally not an issue.  However, they can
exist with a specific kernel configuration and hotplug operations.  For
example: Configure the kernel with CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP.  Then, hotplug add memory for the area where
the gigantic page will be allocated.  Zi Yan outlined steps to reproduce
here [1].

[1] https://lore.kernel.org/linux-mm/16F7C58B-4D79-41C5-9B64-A1A1628F4AF2@nvidia.com/

Link: https://lkml.kernel.org/r/20210217184926.33567-1-mike.kravetz@oracle.com
Fixes: 944d9fec8d7a ("hugetlb: add support for gigantic page allocation at runtime")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/mm/hugetlb.c~hugetlb-fix-update_and_free_page-contig-page-struct-assumption
+++ a/mm/hugetlb.c
@@ -1321,14 +1321,16 @@ static inline void destroy_compound_giga
 static void update_and_free_page(struct hstate *h, struct page *page)
 {
 	int i;
+	struct page *subpage = page;
 
 	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
 		return;
 
 	h->nr_huge_pages--;
 	h->nr_huge_pages_node[page_to_nid(page)]--;
-	for (i = 0; i < pages_per_huge_page(h); i++) {
-		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
+	for (i = 0; i < pages_per_huge_page(h);
+	     i++, subpage = mem_map_next(subpage, page, i)) {
+		subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
 				1 << PG_referenced | 1 << PG_dirty |
 				1 << PG_active | 1 << PG_private |
 				1 << PG_writeback);
_

[patch 131/173] hugetlb: fix copy_huge_page_from_user contig page struct assumption

[Andrew Morton]

From: Mike Kravetz <mike.kravetz@oracle.com>
Subject: hugetlb: fix copy_huge_page_from_user contig page struct assumption

page structs are not guaranteed to be contiguous for gigantic pages.  The
routine copy_huge_page_from_user can encounter gigantic pages, yet it
assumes page structs are contiguous when copying pages from user space.

Since page structs for the target gigantic page are not contiguous, the
data copied from user space could overwrite other pages not associated
with the gigantic page and cause data corruption.

Non-contiguous page structs are generally not an issue.  However, they can
exist with a specific kernel configuration and hotplug operations.  For
example: Configure the kernel with CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP.  Then, hotplug add memory for the area where
the gigantic page will be allocated.

Link: https://lkml.kernel.org/r/20210217184926.33567-2-mike.kravetz@oracle.com
Fixes: 8fb5debc5fcd ("userfaultfd: hugetlbfs: add hugetlb_mcopy_atomic_pte for userfaultfd support")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/mm/memory.c~hugetlb-fix-copy_huge_page_from_user-contig-page-struct-assumption
+++ a/mm/memory.c
@@ -5177,17 +5177,19 @@ long copy_huge_page_from_user(struct pag
 	void *page_kaddr;
 	unsigned long i, rc = 0;
 	unsigned long ret_val = pages_per_huge_page * PAGE_SIZE;
+	struct page *subpage = dst_page;
 
-	for (i = 0; i < pages_per_huge_page; i++) {
+	for (i = 0; i < pages_per_huge_page;
+	     i++, subpage = mem_map_next(subpage, dst_page, i)) {
 		if (allow_pagefault)
-			page_kaddr = kmap(dst_page + i);
+			page_kaddr = kmap(subpage);
 		else
-			page_kaddr = kmap_atomic(dst_page + i);
+			page_kaddr = kmap_atomic(subpage);
 		rc = copy_from_user(page_kaddr,
 				(const void __user *)(src + i * PAGE_SIZE),
 				PAGE_SIZE);
 		if (allow_pagefault)
-			kunmap(dst_page + i);
+			kunmap(subpage);
 		else
 			kunmap_atomic(page_kaddr);
 
_

[patch 152/173] mm/vmscan: restore zone_reclaim_mode ABI

[Andrew Morton]

From: Dave Hansen <dave.hansen@linux.intel.com>
Subject: mm/vmscan: restore zone_reclaim_mode ABI

I went to go add a new RECLAIM_* mode for the zone_reclaim_mode
sysctl.  Like a good kernel developer, I also went to go update the
documentation.  I noticed that the bits in the documentation didn't
match the bits in the #defines.

The VM never explicitly checks the RECLAIM_ZONE bit.  The bit is,
however implicitly checked when checking 'node_reclaim_mode==0'.  The
RECLAIM_ZONE #define was removed in a cleanup.  That, by itself is
fine.

But, when the bit was removed (bit 0) the _other_ bit locations also got
changed.  That's not OK because the bit values are documented to mean one
specific thing.  Users surely do not expect the meaning to change from
kernel to kernel.

The end result is that if someone had a script that did:

	sysctl vm.zone_reclaim_mode=1

it would have gone from enabling node reclaim for clean unmapped pages to
writing out pages during node reclaim after the commit in question. 
That's not great.

Put the bits back the way they were and add a comment so something like
this is a bit harder to do again.  Update the documentation to make it
clear that the first bit is ignored.

Link: https://lkml.kernel.org/r/20210219172555.FF0CDF23@viggo.jf.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Fixes: 648b5cf368e0 ("mm/vmscan: remove unused RECLAIM_OFF/RECLAIM_ZONE")
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Daniel Wagner <dwagner@suse.de>
Cc: "Tobin C. Harding" <tobin@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/admin-guide/sysctl/vm.rst |   10 +++++-----
 mm/vmscan.c                             |    9 +++++++--
 2 files changed, 12 insertions(+), 7 deletions(-)

--- a/Documentation/admin-guide/sysctl/vm.rst~mm-vmscan-restore-zone_reclaim_mode-abi
+++ a/Documentation/admin-guide/sysctl/vm.rst
@@ -983,11 +983,11 @@ that benefit from having their data cach
 left disabled as the caching effect is likely to be more important than
 data locality.
 
-zone_reclaim may be enabled if it's known that the workload is partitioned
-such that each partition fits within a NUMA node and that accessing remote
-memory would cause a measurable performance reduction.  The page allocator
-will then reclaim easily reusable pages (those page cache pages that are
-currently not used) before allocating off node pages.
+Consider enabling one or more zone_reclaim mode bits if it's known that the
+workload is partitioned such that each partition fits within a NUMA node
+and that accessing remote memory would cause a measurable performance
+reduction.  The page allocator will take additional actions before
+allocating off node pages.
 
 Allowing zone reclaim to write out pages stops processes that are
 writing large amounts of data from dirtying pages on other nodes. Zone
--- a/mm/vmscan.c~mm-vmscan-restore-zone_reclaim_mode-abi
+++ a/mm/vmscan.c
@@ -4085,8 +4085,13 @@ module_init(kswapd_init)
  */
 int node_reclaim_mode __read_mostly;
 
-#define RECLAIM_WRITE (1<<0)	/* Writeout pages during reclaim */
-#define RECLAIM_UNMAP (1<<1)	/* Unmap pages during reclaim */
+/*
+ * These bit locations are exposed in the vm.zone_reclaim_mode sysctl
+ * ABI.  New bits are OK, but existing bits can never change.
+ */
+#define RECLAIM_ZONE  (1<<0)   /* Run shrink_inactive_list on the zone */
+#define RECLAIM_WRITE (1<<1)   /* Writeout pages during reclaim */
+#define RECLAIM_UNMAP (1<<2)   /* Unmap pages during reclaim */
 
 /*
  * Priority for NODE_RECLAIM. This determines the fraction of pages
_

[patch 159/173] mm, compaction: make fast_isolate_freepages() stay within zone

[Andrew Morton]

From: Vlastimil Babka <vbabka@suse.cz>
Subject: mm, compaction: make fast_isolate_freepages() stay within zone

Compaction always operates on pages from a single given zone when
isolating both pages to migrate and freepages.  Pageblock boundaries are
intersected with zone boundaries to be safe in case zone starts or ends in
the middle of pageblock.  The use of pageblock_pfn_to_page() protects
against non-contiguous pageblocks.

The functions fast_isolate_freepages() and fast_isolate_around() don't
currently protect the fast freepage isolation thoroughly enough against
these corner cases, and can result in freepage isolation operate outside
of zone boundaries:

- in fast_isolate_freepages() if we get a pfn from the first pageblock
  of a zone that starts in the middle of that pageblock, 'highest' can be
  a pfn outside of the zone.  If we fail to isolate anything in this
  function, we may then call fast_isolate_around() on a pfn outside of the
  zone and there effectively do a set_pageblock_skip(page_to_pfn(highest))
  which may currently hit a VM_BUG_ON() in some configurations

- fast_isolate_around() checks only the zone end boundary and not
  beginning, nor that the pageblock is contiguous (with
  pageblock_pfn_to_page()) so it's possible that we end up calling
  isolate_freepages_block() on a range of pfn's from two different zones
  and end up e.g.  isolating freepages under the wrong zone's lock.

This patch should fix the above issues.

Link: https://lkml.kernel.org/r/20210217173300.6394-1-vbabka@suse.cz
Fixes: 5a811889de10 ("mm, compaction: use free lists to quickly locate a migration target")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/compaction.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

--- a/mm/compaction.c~mm-compaction-make-fast_isolate_freepages-stay-within-zone
+++ a/mm/compaction.c
@@ -1284,7 +1284,7 @@ static void
 fast_isolate_around(struct compact_control *cc, unsigned long pfn, unsigned long nr_isolated)
 {
 	unsigned long start_pfn, end_pfn;
-	struct page *page = pfn_to_page(pfn);
+	struct page *page;
 
 	/* Do not search around if there are enough pages already */
 	if (cc->nr_freepages >= cc->nr_migratepages)
@@ -1295,8 +1295,12 @@ fast_isolate_around(struct compact_contr
 		return;
 
 	/* Pageblock boundaries */
-	start_pfn = pageblock_start_pfn(pfn);
-	end_pfn = min(pageblock_end_pfn(pfn), zone_end_pfn(cc->zone)) - 1;
+	start_pfn = max(pageblock_start_pfn(pfn), cc->zone->zone_start_pfn);
+	end_pfn = min(pageblock_end_pfn(pfn), zone_end_pfn(cc->zone));
+
+	page = pageblock_pfn_to_page(start_pfn, end_pfn, cc->zone);
+	if (!page)
+		return;
 
 	/* Scan before */
 	if (start_pfn != pfn) {
@@ -1398,7 +1402,8 @@ fast_isolate_freepages(struct compact_co
 			pfn = page_to_pfn(freepage);
 
 			if (pfn >= highest)
-				highest = pageblock_start_pfn(pfn);
+				highest = max(pageblock_start_pfn(pfn),
+					      cc->zone->zone_start_pfn);
 
 			if (pfn >= low_pfn) {
 				cc->fast_search_fail = 0;
@@ -1468,7 +1473,8 @@ fast_isolate_freepages(struct compact_co
 			} else {
 				if (cc->direct_compaction && pfn_valid(min_pfn)) {
 					page = pageblock_pfn_to_page(min_pfn,
-						pageblock_end_pfn(min_pfn),
+						min(pageblock_end_pfn(min_pfn),
+						    zone_end_pfn(cc->zone)),
 						cc->zone);
 					cc->free_pfn = min_pfn;
 				}
_