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authorKees Cook <kees+treewide@kernel.org>2026-09-02 15:31:14 -0700
committerKees Cook <kees@kernel.org>2026-09-04 21:37:00 -0700
commit3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch)
treec65086f9bdcd48c6360fb7cb4598bca084da1f32 /fs/proc/page.c
downloadlinux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.tar.gz
linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.zip
treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'fs/proc/page.c')
-rw-r--r--fs/proc/page.c289
1 files changed, 289 insertions, 0 deletions
diff --git a/fs/proc/page.c b/fs/proc/page.c
new file mode 100644
index 000000000..260772b20
--- /dev/null
+++ b/fs/proc/page.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/memblock.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/ksm.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/huge_mm.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/hugetlb.h>
+#include <linux/memremap.h>
+#include <linux/memcontrol.h>
+#include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
+#include <linux/kernel-page-flags.h>
+#include <linux/uaccess.h>
+#include "internal.h"
+
+#define KPMSIZE sizeof(u64)
+#define KPMMASK (KPMSIZE - 1)
+
+enum kpage_operation {
+ KPAGE_FLAGS,
+ KPAGE_COUNT,
+ KPAGE_CGROUP,
+};
+
+static inline unsigned long get_max_dump_pfn(void)
+{
+#ifdef CONFIG_SPARSEMEM
+ /*
+ * The memmap of early sections is completely populated and marked
+ * online even if max_pfn does not fall on a section boundary -
+ * pfn_to_online_page() will succeed on all pages. Allow inspecting
+ * these memmaps.
+ */
+ return round_up(max_pfn, PAGES_PER_SECTION);
+#else
+ return max_pfn;
+#endif
+}
+
+static u64 get_kpage_count(const struct page *page)
+{
+ struct page_snapshot ps;
+ u64 ret;
+
+ snapshot_page(&ps, page);
+
+ if (IS_ENABLED(CONFIG_PAGE_MAPCOUNT))
+ ret = folio_precise_page_mapcount(&ps.folio_snapshot,
+ &ps.page_snapshot);
+ else
+ ret = folio_average_page_mapcount(&ps.folio_snapshot);
+
+ return ret;
+}
+
+static ssize_t kpage_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos,
+ enum kpage_operation op)
+{
+ const unsigned long max_dump_pfn = get_max_dump_pfn();
+ u64 __user *out = (u64 __user *)buf;
+ struct page *page;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+ u64 info;
+
+ pfn = src / KPMSIZE;
+ if (src & KPMMASK || count & KPMMASK)
+ return -EINVAL;
+ if (src >= max_dump_pfn * KPMSIZE)
+ return 0;
+ count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
+
+ while (count > 0) {
+ /*
+ * TODO: ZONE_DEVICE support requires to identify
+ * memmaps that were actually initialized.
+ */
+ page = pfn_to_online_page(pfn);
+
+ if (page) {
+ switch (op) {
+ case KPAGE_FLAGS:
+ info = stable_page_flags(page);
+ break;
+ case KPAGE_COUNT:
+ info = get_kpage_count(page);
+ break;
+ case KPAGE_CGROUP:
+ info = page_cgroup_ino(page);
+ break;
+ default:
+ info = 0;
+ break;
+ }
+ } else
+ info = 0;
+
+ if (put_user(info, out)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ pfn++;
+ out++;
+ count -= KPMSIZE;
+
+ cond_resched();
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+/* /proc/kpagecount - an array exposing page mapcounts
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page mapcount.
+ */
+static ssize_t kpagecount_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ return kpage_read(file, buf, count, ppos, KPAGE_COUNT);
+}
+
+static const struct proc_ops kpagecount_proc_ops = {
+ .proc_flags = PROC_ENTRY_PERMANENT,
+ .proc_lseek = mem_lseek,
+ .proc_read = kpagecount_read,
+};
+
+
+static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
+{
+ return ((kflags >> kbit) & 1) << ubit;
+}
+
+u64 stable_page_flags(const struct page *page)
+{
+ const struct folio *folio;
+ struct page_snapshot ps;
+ unsigned long k;
+ u64 u = 0;
+
+ /*
+ * pseudo flag: KPF_NOPAGE
+ * it differentiates a memory hole from a page with no flags
+ */
+ if (!page)
+ return BIT_ULL(KPF_NOPAGE);
+
+ snapshot_page(&ps, page);
+ folio = &ps.folio_snapshot;
+ k = folio->flags.f;
+
+ /*
+ * pseudo flags for the well known (anonymous) memory mapped pages
+ */
+ if (folio_mapped(folio))
+ u |= BIT_ULL(KPF_MMAP);
+ if (folio_test_anon(folio)) {
+ u |= BIT_ULL(KPF_ANON);
+ if (folio_test_ksm(folio))
+ u |= BIT_ULL(KPF_KSM);
+ }
+
+ /*
+ * compound pages: export both head/tail info
+ * they together define a compound page's start/end pos and order
+ */
+ if (ps.idx == 0)
+ u |= kpf_copy_bit(k, KPF_COMPOUND_HEAD, PG_head);
+ else
+ u |= BIT_ULL(KPF_COMPOUND_TAIL);
+ if (folio_test_hugetlb(folio))
+ u |= BIT_ULL(KPF_HUGE);
+ else if (folio_test_large(folio) &&
+ folio_test_large_rmappable(folio)) {
+ /* Note: we indicate any THPs here, not just PMD-sized ones */
+ u |= BIT_ULL(KPF_THP);
+ } else if (is_huge_zero_pfn(ps.pfn)) {
+ u |= BIT_ULL(KPF_ZERO_PAGE);
+ u |= BIT_ULL(KPF_THP);
+ } else if (is_zero_pfn(ps.pfn)) {
+ u |= BIT_ULL(KPF_ZERO_PAGE);
+ }
+
+ if (ps.flags & PAGE_SNAPSHOT_PG_BUDDY)
+ u |= BIT_ULL(KPF_BUDDY);
+
+ if (ps.flags & PAGE_SNAPSHOT_PG_IDLE)
+ u |= BIT_ULL(KPF_IDLE);
+
+ if (folio_test_offline(folio))
+ u |= BIT_ULL(KPF_OFFLINE);
+ if (folio_test_pgtable(folio))
+ u |= BIT_ULL(KPF_PGTABLE);
+ if (folio_test_slab(folio))
+ u |= BIT_ULL(KPF_SLAB);
+
+ u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
+ u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
+ u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
+ u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
+
+ u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
+ u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
+ u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
+ u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
+
+ if (folio_test_swapcache(folio))
+ u |= BIT_ULL(KPF_SWAPCACHE);
+
+ u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
+ u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
+ u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
+
+#ifdef CONFIG_MEMORY_FAILURE
+ if (u & BIT_ULL(KPF_HUGE))
+ u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
+ else
+ u |= kpf_copy_bit(ps.page_snapshot.flags.f, KPF_HWPOISON, PG_hwpoison);
+#endif
+
+ u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
+ u |= kpf_copy_bit(k, KPF_OWNER_2, PG_owner_2);
+ u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
+ u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
+ u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
+ u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
+#ifdef CONFIG_ARCH_USES_PG_ARCH_2
+ u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2);
+#endif
+#ifdef CONFIG_ARCH_USES_PG_ARCH_3
+ u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3);
+#endif
+
+ return u;
+}
+EXPORT_SYMBOL_GPL(stable_page_flags);
+
+/* /proc/kpageflags - an array exposing page flags
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page flags.
+ */
+static ssize_t kpageflags_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ return kpage_read(file, buf, count, ppos, KPAGE_FLAGS);
+}
+
+static const struct proc_ops kpageflags_proc_ops = {
+ .proc_flags = PROC_ENTRY_PERMANENT,
+ .proc_lseek = mem_lseek,
+ .proc_read = kpageflags_read,
+};
+
+#ifdef CONFIG_MEMCG
+static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ return kpage_read(file, buf, count, ppos, KPAGE_CGROUP);
+}
+static const struct proc_ops kpagecgroup_proc_ops = {
+ .proc_flags = PROC_ENTRY_PERMANENT,
+ .proc_lseek = mem_lseek,
+ .proc_read = kpagecgroup_read,
+};
+#endif /* CONFIG_MEMCG */
+
+static int __init proc_page_init(void)
+{
+ proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
+ proc_create("kpageflags", S_IRUSR, NULL, &kpageflags_proc_ops);
+#ifdef CONFIG_MEMCG
+ proc_create("kpagecgroup", S_IRUSR, NULL, &kpagecgroup_proc_ops);
+#endif
+ return 0;
+}
+fs_initcall(proc_page_init);