Merge tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - In the series "mm: Avoid possible overflows in dirty throttling" Jan
   Kara addresses a couple of issues in the writeback throttling code.
   These fixes are also targetted at -stable kernels.

 - Ryusuke Konishi's series "nilfs2: fix potential issues related to
   reserved inodes" does that. This should actually be in the
   mm-nonmm-stable tree, along with the many other nilfs2 patches. My
   bad.

 - More folio conversions from Kefeng Wang in the series "mm: convert to
   folio_alloc_mpol()"

 - Kemeng Shi has sent some cleanups to the writeback code in the series
   "Add helper functions to remove repeated code and improve readability
   of cgroup writeback"

 - Kairui Song has made the swap code a little smaller and a little
   faster in the series "mm/swap: clean up and optimize swap cache
   index".

 - In the series "mm/memory: cleanly support zeropage in
   vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
   Hildenbrand has reworked the rather sketchy handling of the use of
   the zeropage in MAP_SHARED mappings. I don't see any runtime effects
   here - more a cleanup/understandability/maintainablity thing.

 - Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling
   of higher addresses, for aarch64. The (poorly named) series is
   "Restructure va_high_addr_switch".

 - The core TLB handling code gets some cleanups and possible slight
   optimizations in Bang Li's series "Add update_mmu_tlb_range() to
   simplify code".

 - Jane Chu has improved the handling of our
   fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in
   the series "Enhance soft hwpoison handling and injection".

 - Jeff Johnson has sent a billion patches everywhere to add
   MODULE_DESCRIPTION() to everything. Some landed in this pull.

 - In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang
   has simplified migration's use of hardware-offload memory copying.

 - Yosry Ahmed performs more folio API conversions in his series "mm:
   zswap: trivial folio conversions".

 - In the series "large folios swap-in: handle refault cases first",
   Chuanhua Han inches us forward in the handling of large pages in the
   swap code. This is a cleanup and optimization, working toward the end
   objective of full support of large folio swapin/out.

 - In the series "mm,swap: cleanup VMA based swap readahead window
   calculation", Huang Ying has contributed some cleanups and a possible
   fixlet to his VMA based swap readahead code.

 - In the series "add mTHP support for anonymous shmem" Baolin Wang has
   taught anonymous shmem mappings to use multisize THP. By default this
   is a no-op - users must opt in vis sysfs controls. Dramatic
   improvements in pagefault latency are realized.

 - David Hildenbrand has some cleanups to our remaining use of
   page_mapcount() in the series "fs/proc: move page_mapcount() to
   fs/proc/internal.h".

 - David also has some highmem accounting cleanups in the series
   "mm/highmem: don't track highmem pages manually".

 - Build-time fixes and cleanups from John Hubbard in the series
   "cleanups, fixes, and progress towards avoiding "make headers"".

 - Cleanups and consolidation of the core pagemap handling from Barry
   Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
   and utilize them".

 - Lance Yang's series "Reclaim lazyfree THP without splitting" has
   reduced the latency of the reclaim of pmd-mapped THPs under fairly
   common circumstances. A 10x speedup is seen in a microbenchmark.

   It does this by punting to aother CPU but I guess that's a win unless
   all CPUs are pegged.

 - hugetlb_cgroup cleanups from Xiu Jianfeng in the series
   "mm/hugetlb_cgroup: rework on cftypes".

 - Miaohe Lin's series "Some cleanups for memory-failure" does just that
   thing.

 - Someone other than SeongJae has developed a DAMON feature in Honggyu
   Kim's series "DAMON based tiered memory management for CXL memory".
   This adds DAMON features which may be used to help determine the
   efficiency of our placement of CXL/PCIe attached DRAM.

 - DAMON user API centralization and simplificatio work in SeongJae
   Park's series "mm/damon: introduce DAMON parameters online commit
   function".

 - In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
   David Hildenbrand does some maintenance work on zsmalloc - partially
   modernizing its use of pageframe fields.

 - Kefeng Wang provides more folio conversions in the series "mm: remove
   page_maybe_dma_pinned() and page_mkclean()".

 - More cleanup from David Hildenbrand, this time in the series
   "mm/memory_hotplug: use PageOffline() instead of PageReserved() for
   !ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline()
   pages" and permits the removal of some virtio-mem hacks.

 - Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
   __folio_add_anon_rmap()" is a cleanup to the anon folio handling in
   preparation for mTHP (multisize THP) swapin.

 - Kefeng Wang's series "mm: improve clear and copy user folio"
   implements more folio conversions, this time in the area of large
   folio userspace copying.

 - The series "Docs/mm/damon/maintaier-profile: document a mailing tool
   and community meetup series" tells people how to get better involved
   with other DAMON developers. From SeongJae Park.

 - A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
   that.

 - David Hildenbrand sends along more cleanups, this time against the
   migration code. The series is "mm/migrate: move NUMA hinting fault
   folio isolation + checks under PTL".

 - Jan Kara has found quite a lot of strangenesses and minor errors in
   the readahead code. He addresses this in the series "mm: Fix various
   readahead quirks".

 - SeongJae Park's series "selftests/damon: test DAMOS tried regions and
   {min,max}_nr_regions" adds features and addresses errors in DAMON's
   self testing code.

 - Gavin Shan has found a userspace-triggerable WARN in the pagecache
   code. The series "mm/filemap: Limit page cache size to that supported
   by xarray" addresses this. The series is marked cc:stable.

 - Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
   and cleanup" cleans up and slightly optimizes KSM.

 - Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
   code motion. The series (which also makes the memcg-v1 code
   Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put
   under config option" and "mm: memcg: put cgroup v1-specific memcg
   data under CONFIG_MEMCG_V1"

 - Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
   adds an additional feature to this cgroup-v2 control file.

 - The series "Userspace controls soft-offline pages" from Jiaqi Yan
   permits userspace to stop the kernel's automatic treatment of
   excessive correctable memory errors. In order to permit userspace to
   monitor and handle this situation.

 - Kefeng Wang's series "mm: migrate: support poison recover from
   migrate folio" teaches the kernel to appropriately handle migration
   from poisoned source folios rather than simply panicing.

 - SeongJae Park's series "Docs/damon: minor fixups and improvements"
   does those things.

 - In the series "mm/zsmalloc: change back to per-size_class lock"
   Chengming Zhou improves zsmalloc's scalability and memory
   utilization.

 - Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
   pinning memfd folios" makes the GUP code use FOLL_PIN rather than
   bare refcount increments. So these paes can first be moved aside if
   they reside in the movable zone or a CMA block.

 - Andrii Nakryiko has added a binary ioctl()-based API to
   /proc/pid/maps for much faster reading of vma information. The series
   is "query VMAs from /proc/<pid>/maps".

 - In the series "mm: introduce per-order mTHP split counters" Lance
   Yang improves the kernel's presentation of developer information
   related to multisize THP splitting.

 - Michael Ellerman has developed the series "Reimplement huge pages
   without hugepd on powerpc (8xx, e500, book3s/64)". This permits
   userspace to use all available huge page sizes.

 - In the series "revert unconditional slab and page allocator fault
   injection calls" Vlastimil Babka removes a performance-affecting and
   not very useful feature from slab fault injection.

* tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits)
  mm/mglru: fix ineffective protection calculation
  mm/zswap: fix a white space issue
  mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio
  mm/hugetlb: fix possible recursive locking detected warning
  mm/gup: clear the LRU flag of a page before adding to LRU batch
  mm/numa_balancing: teach mpol_to_str about the balancing mode
  mm: memcg1: convert charge move flags to unsigned long long
  alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting
  lib: reuse page_ext_data() to obtain codetag_ref
  lib: add missing newline character in the warning message
  mm/mglru: fix overshooting shrinker memory
  mm/mglru: fix div-by-zero in vmpressure_calc_level()
  mm/kmemleak: replace strncpy() with strscpy()
  mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC
  mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB
  mm: ignore data-race in __swap_writepage
  hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr
  mm: shmem: rename mTHP shmem counters
  mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async()
  mm/migrate: putback split folios when numa hint migration fails
  ...

3 files changed, 450 insertions, 128 deletions

diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index a71ac5379584..a8a8576d8592 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -13,6 +13,7 @@
 #include <linux/binfmts.h>
 #include <linux/sched/coredump.h>
 #include <linux/sched/task.h>
+#include <linux/mm.h>
 
 struct ctl_table_header;
 struct mempolicy;
@@ -142,6 +143,38 @@ unsigned name_to_int(const struct qstr *qstr);
 /* Worst case buffer size needed for holding an integer. */
 #define PROC_NUMBUF 13
 
+/**
+ * folio_precise_page_mapcount() - Number of mappings of this folio page.
+ * @folio: The folio.
+ * @page: The page.
+ *
+ * The number of present user page table entries that reference this page
+ * as tracked via the RMAP: either referenced directly (PTE) or as part of
+ * a larger area that covers this page (e.g., PMD).
+ *
+ * Use this function only for the calculation of existing statistics
+ * (USS, PSS, mapcount_max) and for debugging purposes (/proc/kpagecount).
+ *
+ * Do not add new users.
+ *
+ * Returns: The number of mappings of this folio page. 0 for
+ * folios that are not mapped to user space or are not tracked via the RMAP
+ * (e.g., shared zeropage).
+ */
+static inline int folio_precise_page_mapcount(struct folio *folio,
+		struct page *page)
+{
+	int mapcount = atomic_read(&page->_mapcount) + 1;
+
+	/* Handle page_has_type() pages */
+	if (mapcount < PAGE_MAPCOUNT_RESERVE + 1)
+		mapcount = 0;
+	if (folio_test_large(folio))
+		mapcount += folio_entire_mapcount(folio);
+
+	return mapcount;
+}
+
 /*
  * array.c
  */
diff --git a/fs/proc/page.c b/fs/proc/page.c
index 2fb64bdb64eb..b7a5c84b5819 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -37,21 +37,19 @@ static inline unsigned long get_max_dump_pfn(void)
 #endif
 }
 
-/* /proc/kpagecount - an array exposing page counts
+/* /proc/kpagecount - an array exposing page mapcounts
  *
  * Each entry is a u64 representing the corresponding
- * physical page count.
+ * physical page mapcount.
  */
 static ssize_t kpagecount_read(struct file *file, char __user *buf,
 			     size_t count, loff_t *ppos)
 {
 	const unsigned long max_dump_pfn = get_max_dump_pfn();
 	u64 __user *out = (u64 __user *)buf;
-	struct page *ppage;
 	unsigned long src = *ppos;
 	unsigned long pfn;
 	ssize_t ret = 0;
-	u64 pcount;
 
 	pfn = src / KPMSIZE;
 	if (src & KPMMASK || count & KPMMASK)
@@ -61,18 +59,19 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf,
 	count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
 
 	while (count > 0) {
+		struct page *page;
+		u64 mapcount = 0;
+
 		/*
 		 * TODO: ZONE_DEVICE support requires to identify
 		 * memmaps that were actually initialized.
 		 */
-		ppage = pfn_to_online_page(pfn);
-
-		if (!ppage)
-			pcount = 0;
-		else
-			pcount = page_mapcount(ppage);
+		page = pfn_to_online_page(pfn);
+		if (page)
+			mapcount = folio_precise_page_mapcount(page_folio(page),
+							       page);
 
-		if (put_user(pcount, out)) {
+		if (put_user(mapcount, out)) {
 			ret = -EFAULT;
 			break;
 		}
@@ -148,19 +147,16 @@ u64 stable_page_flags(const struct page *page)
 		u |= 1 << KPF_COMPOUND_TAIL;
 	if (folio_test_hugetlb(folio))
 		u |= 1 << KPF_HUGE;
-	/*
-	 * We need to check PageLRU/PageAnon
-	 * to make sure a given page is a thp, not a non-huge compound page.
-	 */
-	else if (folio_test_large(folio)) {
-		if ((k & (1 << PG_lru)) || is_anon)
-			u |= 1 << KPF_THP;
-		else if (is_huge_zero_folio(folio)) {
-			u |= 1 << KPF_ZERO_PAGE;
-			u |= 1 << KPF_THP;
-		}
-	} else if (is_zero_pfn(page_to_pfn(page)))
+	else if (folio_test_large(folio) &&
+	         folio_test_large_rmappable(folio)) {
+		/* Note: we indicate any THPs here, not just PMD-sized ones */
+		u |= 1 << KPF_THP;
+	} else if (is_huge_zero_folio(folio)) {
 		u |= 1 << KPF_ZERO_PAGE;
+		u |= 1 << KPF_THP;
+	} else if (is_zero_folio(folio)) {
+		u |= 1 << KPF_ZERO_PAGE;
+	}
 
 	/*
 	 * Caveats on high order pages: PG_buddy and PG_slab will only be set
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 71e5039d940d..775a2e8d600c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -22,6 +22,7 @@
 #include <linux/pkeys.h>
 #include <linux/minmax.h>
 #include <linux/overflow.h>
+#include <linux/buildid.h>
 
 #include <asm/elf.h>
 #include <asm/tlb.h>
@@ -239,6 +240,67 @@ static int do_maps_open(struct inode *inode, struct file *file,
 				sizeof(struct proc_maps_private));
 }
 
+static void get_vma_name(struct vm_area_struct *vma,
+			 const struct path **path,
+			 const char **name,
+			 const char **name_fmt)
+{
+	struct anon_vma_name *anon_name = vma->vm_mm ? anon_vma_name(vma) : NULL;
+
+	*name = NULL;
+	*path = NULL;
+	*name_fmt = NULL;
+
+	/*
+	 * Print the dentry name for named mappings, and a
+	 * special [heap] marker for the heap:
+	 */
+	if (vma->vm_file) {
+		/*
+		 * If user named this anon shared memory via
+		 * prctl(PR_SET_VMA ..., use the provided name.
+		 */
+		if (anon_name) {
+			*name_fmt = "[anon_shmem:%s]";
+			*name = anon_name->name;
+		} else {
+			*path = file_user_path(vma->vm_file);
+		}
+		return;
+	}
+
+	if (vma->vm_ops && vma->vm_ops->name) {
+		*name = vma->vm_ops->name(vma);
+		if (*name)
+			return;
+	}
+
+	*name = arch_vma_name(vma);
+	if (*name)
+		return;
+
+	if (!vma->vm_mm) {
+		*name = "[vdso]";
+		return;
+	}
+
+	if (vma_is_initial_heap(vma)) {
+		*name = "[heap]";
+		return;
+	}
+
+	if (vma_is_initial_stack(vma)) {
+		*name = "[stack]";
+		return;
+	}
+
+	if (anon_name) {
+		*name_fmt = "[anon:%s]";
+		*name = anon_name->name;
+		return;
+	}
+}
+
 static void show_vma_header_prefix(struct seq_file *m,
 				   unsigned long start, unsigned long end,
 				   vm_flags_t flags, unsigned long long pgoff,
@@ -262,17 +324,15 @@ static void show_vma_header_prefix(struct seq_file *m,
 static void
 show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
 {
-	struct anon_vma_name *anon_name = NULL;
-	struct mm_struct *mm = vma->vm_mm;
-	struct file *file = vma->vm_file;
+	const struct path *path;
+	const char *name_fmt, *name;
 	vm_flags_t flags = vma->vm_flags;
 	unsigned long ino = 0;
 	unsigned long long pgoff = 0;
 	unsigned long start, end;
 	dev_t dev = 0;
-	const char *name = NULL;
 
-	if (file) {
+	if (vma->vm_file) {
 		const struct inode *inode = file_user_inode(vma->vm_file);
 
 		dev = inode->i_sb->s_dev;
@@ -283,57 +343,15 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
 	start = vma->vm_start;
 	end = vma->vm_end;
 	show_vma_header_prefix(m, start, end, flags, pgoff, dev, ino);
-	if (mm)
-		anon_name = anon_vma_name(vma);
 
-	/*
-	 * Print the dentry name for named mappings, and a
-	 * special [heap] marker for the heap:
-	 */
-	if (file) {
+	get_vma_name(vma, &path, &name, &name_fmt);
+	if (path) {
 		seq_pad(m, ' ');
-		/*
-		 * If user named this anon shared memory via
-		 * prctl(PR_SET_VMA ..., use the provided name.
-		 */
-		if (anon_name)
-			seq_printf(m, "[anon_shmem:%s]", anon_name->name);
-		else
-			seq_path(m, file_user_path(file), "\n");
-		goto done;
-	}
-
-	if (vma->vm_ops && vma->vm_ops->name) {
-		name = vma->vm_ops->name(vma);
-		if (name)
-			goto done;
-	}
-
-	name = arch_vma_name(vma);
-	if (!name) {
-		if (!mm) {
-			name = "[vdso]";
-			goto done;
-		}
-
-		if (vma_is_initial_heap(vma)) {
-			name = "[heap]";
-			goto done;
-		}
-
-		if (vma_is_initial_stack(vma)) {
-			name = "[stack]";
-			goto done;
-		}
-
-		if (anon_name) {
-			seq_pad(m, ' ');
-			seq_printf(m, "[anon:%s]", anon_name->name);
-		}
-	}
-
-done:
-	if (name) {
+		seq_path(m, path, "\n");
+	} else if (name_fmt) {
+		seq_pad(m, ' ');
+		seq_printf(m, name_fmt, name);
+	} else if (name) {
 		seq_pad(m, ' ');
 		seq_puts(m, name);
 	}
@@ -358,11 +376,268 @@ static int pid_maps_open(struct inode *inode, struct file *file)
 	return do_maps_open(inode, file, &proc_pid_maps_op);
 }
 
+#define PROCMAP_QUERY_VMA_FLAGS (				\
+		PROCMAP_QUERY_VMA_READABLE |			\
+		PROCMAP_QUERY_VMA_WRITABLE |			\
+		PROCMAP_QUERY_VMA_EXECUTABLE |			\
+		PROCMAP_QUERY_VMA_SHARED			\
+)
+
+#define PROCMAP_QUERY_VALID_FLAGS_MASK (			\
+		PROCMAP_QUERY_COVERING_OR_NEXT_VMA |		\
+		PROCMAP_QUERY_FILE_BACKED_VMA |			\
+		PROCMAP_QUERY_VMA_FLAGS				\
+)
+
+static int query_vma_setup(struct mm_struct *mm)
+{
+	return mmap_read_lock_killable(mm);
+}
+
+static void query_vma_teardown(struct mm_struct *mm, struct vm_area_struct *vma)
+{
+	mmap_read_unlock(mm);
+}
+
+static struct vm_area_struct *query_vma_find_by_addr(struct mm_struct *mm, unsigned long addr)
+{
+	return find_vma(mm, addr);
+}
+
+static struct vm_area_struct *query_matching_vma(struct mm_struct *mm,
+						 unsigned long addr, u32 flags)
+{
+	struct vm_area_struct *vma;
+
+next_vma:
+	vma = query_vma_find_by_addr(mm, addr);
+	if (!vma)
+		goto no_vma;
+
+	/* user requested only file-backed VMA, keep iterating */
+	if ((flags & PROCMAP_QUERY_FILE_BACKED_VMA) && !vma->vm_file)
+		goto skip_vma;
+
+	/* VMA permissions should satisfy query flags */
+	if (flags & PROCMAP_QUERY_VMA_FLAGS) {
+		u32 perm = 0;
+
+		if (flags & PROCMAP_QUERY_VMA_READABLE)
+			perm |= VM_READ;
+		if (flags & PROCMAP_QUERY_VMA_WRITABLE)
+			perm |= VM_WRITE;
+		if (flags & PROCMAP_QUERY_VMA_EXECUTABLE)
+			perm |= VM_EXEC;
+		if (flags & PROCMAP_QUERY_VMA_SHARED)
+			perm |= VM_MAYSHARE;
+
+		if ((vma->vm_flags & perm) != perm)
+			goto skip_vma;
+	}
+
+	/* found covering VMA or user is OK with the matching next VMA */
+	if ((flags & PROCMAP_QUERY_COVERING_OR_NEXT_VMA) || vma->vm_start <= addr)
+		return vma;
+
+skip_vma:
+	/*
+	 * If the user needs closest matching VMA, keep iterating.
+	 */
+	addr = vma->vm_end;
+	if (flags & PROCMAP_QUERY_COVERING_OR_NEXT_VMA)
+		goto next_vma;
+
+no_vma:
+	return ERR_PTR(-ENOENT);
+}
+
+static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
+{
+	struct procmap_query karg;
+	struct vm_area_struct *vma;
+	struct mm_struct *mm;
+	const char *name = NULL;
+	char build_id_buf[BUILD_ID_SIZE_MAX], *name_buf = NULL;
+	__u64 usize;
+	int err;
+
+	if (copy_from_user(&usize, (void __user *)uarg, sizeof(usize)))
+		return -EFAULT;
+	/* argument struct can never be that large, reject abuse */
+	if (usize > PAGE_SIZE)
+		return -E2BIG;
+	/* argument struct should have at least query_flags and query_addr fields */
+	if (usize < offsetofend(struct procmap_query, query_addr))
+		return -EINVAL;
+	err = copy_struct_from_user(&karg, sizeof(karg), uarg, usize);
+	if (err)
+		return err;
+
+	/* reject unknown flags */
+	if (karg.query_flags & ~PROCMAP_QUERY_VALID_FLAGS_MASK)
+		return -EINVAL;
+	/* either both buffer address and size are set, or both should be zero */
+	if (!!karg.vma_name_size != !!karg.vma_name_addr)
+		return -EINVAL;
+	if (!!karg.build_id_size != !!karg.build_id_addr)
+		return -EINVAL;
+
+	mm = priv->mm;
+	if (!mm || !mmget_not_zero(mm))
+		return -ESRCH;
+
+	err = query_vma_setup(mm);
+	if (err) {
+		mmput(mm);
+		return err;
+	}
+
+	vma = query_matching_vma(mm, karg.query_addr, karg.query_flags);
+	if (IS_ERR(vma)) {
+		err = PTR_ERR(vma);
+		vma = NULL;
+		goto out;
+	}
+
+	karg.vma_start = vma->vm_start;
+	karg.vma_end = vma->vm_end;
+
+	karg.vma_flags = 0;
+	if (vma->vm_flags & VM_READ)
+		karg.vma_flags |= PROCMAP_QUERY_VMA_READABLE;
+	if (vma->vm_flags & VM_WRITE)
+		karg.vma_flags |= PROCMAP_QUERY_VMA_WRITABLE;
+	if (vma->vm_flags & VM_EXEC)
+		karg.vma_flags |= PROCMAP_QUERY_VMA_EXECUTABLE;
+	if (vma->vm_flags & VM_MAYSHARE)
+		karg.vma_flags |= PROCMAP_QUERY_VMA_SHARED;
+
+	karg.vma_page_size = vma_kernel_pagesize(vma);
+
+	if (vma->vm_file) {
+		const struct inode *inode = file_user_inode(vma->vm_file);
+
+		karg.vma_offset = ((__u64)vma->vm_pgoff) << PAGE_SHIFT;
+		karg.dev_major = MAJOR(inode->i_sb->s_dev);
+		karg.dev_minor = MINOR(inode->i_sb->s_dev);
+		karg.inode = inode->i_ino;
+	} else {
+		karg.vma_offset = 0;
+		karg.dev_major = 0;
+		karg.dev_minor = 0;
+		karg.inode = 0;
+	}
+
+	if (karg.build_id_size) {
+		__u32 build_id_sz;
+
+		err = build_id_parse(vma, build_id_buf, &build_id_sz);
+		if (err) {
+			karg.build_id_size = 0;
+		} else {
+			if (karg.build_id_size < build_id_sz) {
+				err = -ENAMETOOLONG;
+				goto out;
+			}
+			karg.build_id_size = build_id_sz;
+		}
+	}
+
+	if (karg.build_id_size) {
+		__u32 build_id_sz;
+
+		err = build_id_parse(vma, build_id_buf, &build_id_sz);
+		if (err) {
+			karg.build_id_size = 0;
+		} else {
+			if (karg.build_id_size < build_id_sz) {
+				err = -ENAMETOOLONG;
+				goto out;
+			}
+			karg.build_id_size = build_id_sz;
+		}
+	}
+
+	if (karg.vma_name_size) {
+		size_t name_buf_sz = min_t(size_t, PATH_MAX, karg.vma_name_size);
+		const struct path *path;
+		const char *name_fmt;
+		size_t name_sz = 0;
+
+		get_vma_name(vma, &path, &name, &name_fmt);
+
+		if (path || name_fmt || name) {
+			name_buf = kmalloc(name_buf_sz, GFP_KERNEL);
+			if (!name_buf) {
+				err = -ENOMEM;
+				goto out;
+			}
+		}
+		if (path) {
+			name = d_path(path, name_buf, name_buf_sz);
+			if (IS_ERR(name)) {
+				err = PTR_ERR(name);
+				goto out;
+			}
+			name_sz = name_buf + name_buf_sz - name;
+		} else if (name || name_fmt) {
+			name_sz = 1 + snprintf(name_buf, name_buf_sz, name_fmt ?: "%s", name);
+			name = name_buf;
+		}
+		if (name_sz > name_buf_sz) {
+			err = -ENAMETOOLONG;
+			goto out;
+		}
+		karg.vma_name_size = name_sz;
+	}
+
+	/* unlock vma or mmap_lock, and put mm_struct before copying data to user */
+	query_vma_teardown(mm, vma);
+	mmput(mm);
+
+	if (karg.vma_name_size && copy_to_user(u64_to_user_ptr(karg.vma_name_addr),
+					       name, karg.vma_name_size)) {
+		kfree(name_buf);
+		return -EFAULT;
+	}
+	kfree(name_buf);
+
+	if (karg.build_id_size && copy_to_user(u64_to_user_ptr(karg.build_id_addr),
+					       build_id_buf, karg.build_id_size))
+		return -EFAULT;
+
+	if (copy_to_user(uarg, &karg, min_t(size_t, sizeof(karg), usize)))
+		return -EFAULT;
+
+	return 0;
+
+out:
+	query_vma_teardown(mm, vma);
+	mmput(mm);
+	kfree(name_buf);
+	return err;
+}
+
+static long procfs_procmap_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct seq_file *seq = file->private_data;
+	struct proc_maps_private *priv = seq->private;
+
+	switch (cmd) {
+	case PROCMAP_QUERY:
+		return do_procmap_query(priv, (void __user *)arg);
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
 const struct file_operations proc_pid_maps_operations = {
 	.open		= pid_maps_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= proc_map_release,
+	.unlocked_ioctl = procfs_procmap_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
 };
 
 /*
@@ -442,7 +717,7 @@ static void smaps_page_accumulate(struct mem_size_stats *mss,
 
 static void smaps_account(struct mem_size_stats *mss, struct page *page,
 		bool compound, bool young, bool dirty, bool locked,
-		bool migration)
+		bool present)
 {
 	struct folio *folio = page_folio(page);
 	int i, nr = compound ? compound_nr(page) : 1;
@@ -471,24 +746,29 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
 	 * Then accumulate quantities that may depend on sharing, or that may
 	 * differ page-by-page.
 	 *
-	 * refcount == 1 guarantees the page is mapped exactly once.
-	 * If any subpage of the compound page mapped with PTE it would elevate
-	 * the refcount.
+	 * refcount == 1 for present entries guarantees that the folio is mapped
+	 * exactly once. For large folios this implies that exactly one
+	 * PTE/PMD/... maps (a part of) this folio.
 	 *
-	 * The page_mapcount() is called to get a snapshot of the mapcount.
-	 * Without holding the page lock this snapshot can be slightly wrong as
-	 * we cannot always read the mapcount atomically.  It is not safe to
-	 * call page_mapcount() even with PTL held if the page is not mapped,
-	 * especially for migration entries.  Treat regular migration entries
-	 * as mapcount == 1.
+	 * Treat all non-present entries (where relying on the mapcount and
+	 * refcount doesn't make sense) as "maybe shared, but not sure how
+	 * often". We treat device private entries as being fake-present.
+	 *
+	 * Note that it would not be safe to read the mapcount especially for
+	 * pages referenced by migration entries, even with the PTL held.
 	 */
-	if ((folio_ref_count(folio) == 1) || migration) {
+	if (folio_ref_count(folio) == 1 || !present) {
 		smaps_page_accumulate(mss, folio, size, size << PSS_SHIFT,
-				dirty, locked, true);
+				      dirty, locked, present);
 		return;
 	}
+	/*
+	 * We obtain a snapshot of the mapcount. Without holding the folio lock
+	 * this snapshot can be slightly wrong as we cannot always read the
+	 * mapcount atomically.
+	 */
 	for (i = 0; i < nr; i++, page++) {
-		int mapcount = page_mapcount(page);
+		int mapcount = folio_precise_page_mapcount(folio, page);
 		unsigned long pss = PAGE_SIZE << PSS_SHIFT;
 		if (mapcount >= 2)
 			pss /= mapcount;
@@ -531,13 +811,14 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 	struct vm_area_struct *vma = walk->vma;
 	bool locked = !!(vma->vm_flags & VM_LOCKED);
 	struct page *page = NULL;
-	bool migration = false, young = false, dirty = false;
+	bool present = false, young = false, dirty = false;
 	pte_t ptent = ptep_get(pte);
 
 	if (pte_present(ptent)) {
 		page = vm_normal_page(vma, addr, ptent);
 		young = pte_young(ptent);
 		dirty = pte_dirty(ptent);
+		present = true;
 	} else if (is_swap_pte(ptent)) {
 		swp_entry_t swpent = pte_to_swp_entry(ptent);
 
@@ -555,8 +836,8 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 				mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
 			}
 		} else if (is_pfn_swap_entry(swpent)) {
-			if (is_migration_entry(swpent))
-				migration = true;
+			if (is_device_private_entry(swpent))
+				present = true;
 			page = pfn_swap_entry_to_page(swpent);
 		}
 	} else {
@@ -567,7 +848,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 	if (!page)
 		return;
 
-	smaps_account(mss, page, false, young, dirty, locked, migration);
+	smaps_account(mss, page, false, young, dirty, locked, present);
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -578,18 +859,17 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 	struct vm_area_struct *vma = walk->vma;
 	bool locked = !!(vma->vm_flags & VM_LOCKED);
 	struct page *page = NULL;
+	bool present = false;
 	struct folio *folio;
-	bool migration = false;
 
 	if (pmd_present(*pmd)) {
 		page = vm_normal_page_pmd(vma, addr, *pmd);
+		present = true;
 	} else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {
 		swp_entry_t entry = pmd_to_swp_entry(*pmd);
 
-		if (is_migration_entry(entry)) {
-			migration = true;
+		if (is_pfn_swap_entry(entry))
 			page = pfn_swap_entry_to_page(entry);
-		}
 	}
 	if (IS_ERR_OR_NULL(page))
 		return;
@@ -604,7 +884,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 		mss->file_thp += HPAGE_PMD_SIZE;
 
 	smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd),
-		      locked, migration);
+		      locked, present);
 }
 #else
 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
@@ -733,19 +1013,23 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 {
 	struct mem_size_stats *mss = walk->private;
 	struct vm_area_struct *vma = walk->vma;
-	pte_t ptent = huge_ptep_get(pte);
+	pte_t ptent = huge_ptep_get(walk->mm, addr, pte);
 	struct folio *folio = NULL;
+	bool present = false;
 
 	if (pte_present(ptent)) {
 		folio = page_folio(pte_page(ptent));
+		present = true;
 	} else if (is_swap_pte(ptent)) {
 		swp_entry_t swpent = pte_to_swp_entry(ptent);
 
 		if (is_pfn_swap_entry(swpent))
 			folio = pfn_swap_entry_folio(swpent);
 	}
+
 	if (folio) {
-		if (folio_likely_mapped_shared(folio) ||
+		/* We treat non-present entries as "maybe shared". */
+		if (!present || folio_likely_mapped_shared(folio) ||
 		    hugetlb_pmd_shared(pte))
 			mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
 		else
@@ -1091,7 +1375,7 @@ struct clear_refs_private {
 
 static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 {
-	struct page *page;
+	struct folio *folio;
 
 	if (!pte_write(pte))
 		return false;
@@ -1099,10 +1383,10 @@ static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr,
 		return false;
 	if (likely(!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)))
 		return false;
-	page = vm_normal_page(vma, addr, pte);
-	if (!page)
+	folio = vm_normal_folio(vma, addr, pte);
+	if (!folio)
 		return false;
-	return page_maybe_dma_pinned(page);
+	return folio_maybe_dma_pinned(folio);
 }
 
 static inline void clear_soft_dirty(struct vm_area_struct *vma,
@@ -1418,7 +1702,7 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
 {
 	u64 frame = 0, flags = 0;
 	struct page *page = NULL;
-	bool migration = false;
+	struct folio *folio;
 
 	if (pte_present(pte)) {
 		if (pm->show_pfn)
@@ -1450,17 +1734,20 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
 			    (offset << MAX_SWAPFILES_SHIFT);
 		}
 		flags |= PM_SWAP;
-		migration = is_migration_entry(entry);
 		if (is_pfn_swap_entry(entry))
 			page = pfn_swap_entry_to_page(entry);
 		if (pte_marker_entry_uffd_wp(entry))
 			flags |= PM_UFFD_WP;
 	}
 
-	if (page && !PageAnon(page))
-		flags |= PM_FILE;
-	if (page && !migration && page_mapcount(page) == 1)
-		flags |= PM_MMAP_EXCLUSIVE;
+	if (page) {
+		folio = page_folio(page);
+		if (!folio_test_anon(folio))
+			flags |= PM_FILE;
+		if ((flags & PM_PRESENT) &&
+		    folio_precise_page_mapcount(folio, page) == 1)
+			flags |= PM_MMAP_EXCLUSIVE;
+	}
 	if (vma->vm_flags & VM_SOFTDIRTY)
 		flags |= PM_SOFT_DIRTY;
 
@@ -1476,13 +1763,14 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
 	pte_t *pte, *orig_pte;
 	int err = 0;
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	bool migration = false;
 
 	ptl = pmd_trans_huge_lock(pmdp, vma);
 	if (ptl) {
+		unsigned int idx = (addr & ~PMD_MASK) >> PAGE_SHIFT;
 		u64 flags = 0, frame = 0;
 		pmd_t pmd = *pmdp;
 		struct page *page = NULL;
+		struct folio *folio = NULL;
 
 		if (vma->vm_flags & VM_SOFTDIRTY)
 			flags |= PM_SOFT_DIRTY;
@@ -1496,8 +1784,7 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
 			if (pmd_uffd_wp(pmd))
 				flags |= PM_UFFD_WP;
 			if (pm->show_pfn)
-				frame = pmd_pfn(pmd) +
-					((addr & ~PMD_MASK) >> PAGE_SHIFT);
+				frame = pmd_pfn(pmd) + idx;
 		}
 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
 		else if (is_swap_pmd(pmd)) {
@@ -1506,11 +1793,9 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
 
 			if (pm->show_pfn) {
 				if (is_pfn_swap_entry(entry))
-					offset = swp_offset_pfn(entry);
+					offset = swp_offset_pfn(entry) + idx;
 				else
-					offset = swp_offset(entry);
-				offset = offset +
-					((addr & ~PMD_MASK) >> PAGE_SHIFT);
+					offset = swp_offset(entry) + idx;
 				frame = swp_type(entry) |
 					(offset << MAX_SWAPFILES_SHIFT);
 			}
@@ -1520,17 +1805,25 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
 			if (pmd_swp_uffd_wp(pmd))
 				flags |= PM_UFFD_WP;
 			VM_BUG_ON(!is_pmd_migration_entry(pmd));
-			migration = is_migration_entry(entry);
 			page = pfn_swap_entry_to_page(entry);
 		}
 #endif
 
-		if (page && !migration && page_mapcount(page) == 1)
-			flags |= PM_MMAP_EXCLUSIVE;
+		if (page) {
+			folio = page_folio(page);
+			if (!folio_test_anon(folio))
+				flags |= PM_FILE;
+		}
+
+		for (; addr != end; addr += PAGE_SIZE, idx++) {
+			unsigned long cur_flags = flags;
+			pagemap_entry_t pme;
 
-		for (; addr != end; addr += PAGE_SIZE) {
-			pagemap_entry_t pme = make_pme(frame, flags);
+			if (folio && (flags & PM_PRESENT) &&
+			    folio_precise_page_mapcount(folio, page + idx) == 1)
+				cur_flags |= PM_MMAP_EXCLUSIVE;
 
+			pme = make_pme(frame, cur_flags);
 			err = add_to_pagemap(&pme, pm);
 			if (err)
 				break;
@@ -1585,7 +1878,7 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
 	if (vma->vm_flags & VM_SOFTDIRTY)
 		flags |= PM_SOFT_DIRTY;
 
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(walk->mm, addr, ptep);
 	if (pte_present(pte)) {
 		struct folio *folio = page_folio(pte_page(pte));
 
@@ -2274,7 +2567,7 @@ static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
 	if (~p->arg.flags & PM_SCAN_WP_MATCHING) {
 		/* Go the short route when not write-protecting pages. */
 
-		pte = huge_ptep_get(ptep);
+		pte = huge_ptep_get(walk->mm, start, ptep);
 		categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
 
 		if (!pagemap_scan_is_interesting_page(categories, p))
@@ -2286,7 +2579,7 @@ static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
 	i_mmap_lock_write(vma->vm_file->f_mapping);
 	ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, ptep);
 
-	pte = huge_ptep_get(ptep);
+	pte = huge_ptep_get(walk->mm, start, ptep);
 	categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
 
 	if (!pagemap_scan_is_interesting_page(categories, p))
@@ -2566,7 +2859,7 @@ static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
 			unsigned long nr_pages)
 {
 	struct folio *folio = page_folio(page);
-	int count = page_mapcount(page);
+	int count = folio_precise_page_mapcount(folio, page);
 
 	md->pages += nr_pages;
 	if (pte_dirty || folio_test_dirty(folio))
@@ -2682,7 +2975,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 		unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
-	pte_t huge_pte = huge_ptep_get(pte);
+	pte_t huge_pte = huge_ptep_get(walk->mm, addr, pte);
 	struct numa_maps *md;
 	struct page *page;