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| author | Kees Cook <kees+treewide@kernel.org> | 2026-09-02 15:31:14 -0700 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2026-09-04 21:37:00 -0700 |
| commit | 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch) | |
| tree | c65086f9bdcd48c6360fb7cb4598bca084da1f32 /fs/proc/page.c | |
| download | linux-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.c | 289 |
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); |
