From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/mm/debug.c | 182 +++++++++++++++++++++++++++++++++++++++++----
1 files changed, 165 insertions(+), 17 deletions(-)
diff --git a/kernel/mm/debug.c b/kernel/mm/debug.c
index bd10aad..aa44dea 100644
--- a/kernel/mm/debug.c
+++ b/kernel/mm/debug.c
@@ -13,10 +13,12 @@
#include <trace/events/mmflags.h>
#include <linux/migrate.h>
#include <linux/page_owner.h>
+#include <linux/page_pinner.h>
+#include <linux/ctype.h>
#include "internal.h"
-char *migrate_reason_names[MR_TYPES] = {
+const char *migrate_reason_names[MR_TYPES] = {
"compaction",
"memory_failure",
"memory_hotplug",
@@ -43,8 +45,19 @@
void __dump_page(struct page *page, const char *reason)
{
+ struct page *head = compound_head(page);
+ struct address_space *mapping;
bool page_poisoned = PagePoisoned(page);
+ bool compound = PageCompound(page);
+ /*
+ * Accessing the pageblock without the zone lock. It could change to
+ * "isolate" again in the meantime, but since we are just dumping the
+ * state for debugging, it should be fine to accept a bit of
+ * inaccuracy here due to racing.
+ */
+ bool page_cma = is_migrate_cma_page(page);
int mapcount;
+ char *type = "";
/*
* If struct page is poisoned don't access Page*() functions as that
@@ -52,8 +65,28 @@
* dump_page() when detected.
*/
if (page_poisoned) {
- pr_emerg("page:%px is uninitialized and poisoned", page);
+ pr_warn("page:%px is uninitialized and poisoned", page);
goto hex_only;
+ }
+
+ if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
+ /*
+ * Corrupt page, so we cannot call page_mapping. Instead, do a
+ * safe subset of the steps that page_mapping() does. Caution:
+ * this will be misleading for tail pages, PageSwapCache pages,
+ * and potentially other situations. (See the page_mapping()
+ * implementation for what's missing here.)
+ */
+ unsigned long tmp = (unsigned long)page->mapping;
+
+ if (tmp & PAGE_MAPPING_ANON)
+ mapping = NULL;
+ else
+ mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
+ head = page;
+ compound = false;
+ } else {
+ mapping = page_mapping(page);
}
/*
@@ -61,29 +94,97 @@
* page->_mapcount space in struct page is used by sl[aou]b pages to
* encode own info.
*/
- mapcount = PageSlab(page) ? 0 : page_mapcount(page);
+ mapcount = PageSlab(head) ? 0 : page_mapcount(page);
- pr_emerg("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
- page, page_ref_count(page), mapcount,
- page->mapping, page_to_pgoff(page));
- if (PageCompound(page))
- pr_cont(" compound_mapcount: %d", compound_mapcount(page));
- pr_cont("\n");
+ pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
+ page, page_ref_count(head), mapcount, mapping,
+ page_to_pgoff(page), page_to_pfn(page));
+ if (compound) {
+ if (hpage_pincount_available(page)) {
+ pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
+ head, compound_order(head),
+ head_compound_mapcount(head),
+ head_compound_pincount(head));
+ } else {
+ pr_warn("head:%p order:%u compound_mapcount:%d\n",
+ head, compound_order(head),
+ head_compound_mapcount(head));
+ }
+ }
+ if (PageKsm(page))
+ type = "ksm ";
+ else if (PageAnon(page))
+ type = "anon ";
+ else if (mapping) {
+ struct inode *host;
+ const struct address_space_operations *a_ops;
+ struct hlist_node *dentry_first;
+ struct dentry *dentry_ptr;
+ struct dentry dentry;
+ unsigned long ino;
+
+ /*
+ * mapping can be invalid pointer and we don't want to crash
+ * accessing it, so probe everything depending on it carefully
+ */
+ if (get_kernel_nofault(host, &mapping->host) ||
+ get_kernel_nofault(a_ops, &mapping->a_ops)) {
+ pr_warn("failed to read mapping contents, not a valid kernel address?\n");
+ goto out_mapping;
+ }
+
+ if (!host) {
+ pr_warn("aops:%ps\n", a_ops);
+ goto out_mapping;
+ }
+
+ if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
+ get_kernel_nofault(ino, &host->i_ino)) {
+ pr_warn("aops:%ps with invalid host inode %px\n",
+ a_ops, host);
+ goto out_mapping;
+ }
+
+ if (!dentry_first) {
+ pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
+ goto out_mapping;
+ }
+
+ dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
+ if (get_kernel_nofault(dentry, dentry_ptr)) {
+ pr_warn("aops:%ps ino:%lx with invalid dentry %px\n",
+ a_ops, ino, dentry_ptr);
+ } else {
+ /*
+ * if dentry is corrupted, the %pd handler may still
+ * crash, but it's unlikely that we reach here with a
+ * corrupted struct page
+ */
+ pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
+ a_ops, ino, &dentry);
+ }
+ }
+out_mapping:
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
- pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
+ pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
+ page_cma ? " CMA" : "");
hex_only:
- print_hex_dump(KERN_ALERT, "raw: ", DUMP_PREFIX_NONE, 32,
+ print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
sizeof(unsigned long), page,
+ sizeof(struct page), false);
+ if (head != page)
+ print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
+ sizeof(unsigned long), head,
sizeof(struct page), false);
if (reason)
- pr_alert("page dumped because: %s\n", reason);
+ pr_warn("page dumped because: %s\n", reason);
#ifdef CONFIG_MEMCG
if (!page_poisoned && page->mem_cgroup)
- pr_alert("page->mem_cgroup:%px\n", page->mem_cgroup);
+ pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
#endif
}
@@ -91,6 +192,7 @@
{
__dump_page(page, reason);
dump_page_owner(page);
+ dump_page_pinner(page);
}
EXPORT_SYMBOL(dump_page);
@@ -121,7 +223,7 @@
"mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
"hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
- "pinned_vm %lx data_vm %lx exec_vm %lx stack_vm %lx\n"
+ "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
"start_code %lx end_code %lx start_data %lx end_data %lx\n"
"start_brk %lx brk %lx start_stack %lx\n"
"arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
@@ -134,7 +236,7 @@
#endif
"exe_file %px\n"
#ifdef CONFIG_MMU_NOTIFIER
- "mmu_notifier_mm %px\n"
+ "notifier_subscriptions %px\n"
#endif
#ifdef CONFIG_NUMA_BALANCING
"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
@@ -152,7 +254,8 @@
mm_pgtables_bytes(mm),
mm->map_count,
mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
- mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm,
+ (u64)atomic64_read(&mm->pinned_vm),
+ mm->data_vm, mm->exec_vm, mm->stack_vm,
mm->start_code, mm->end_code, mm->start_data, mm->end_data,
mm->start_brk, mm->brk, mm->start_stack,
mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
@@ -165,7 +268,7 @@
#endif
mm->exe_file,
#ifdef CONFIG_MMU_NOTIFIER
- mm->mmu_notifier_mm,
+ mm->notifier_subscriptions,
#endif
#ifdef CONFIG_NUMA_BALANCING
mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
@@ -175,4 +278,49 @@
);
}
+static bool page_init_poisoning __read_mostly = true;
+
+static int __init setup_vm_debug(char *str)
+{
+ bool __page_init_poisoning = true;
+
+ /*
+ * Calling vm_debug with no arguments is equivalent to requesting
+ * to enable all debugging options we can control.
+ */
+ if (*str++ != '=' || !*str)
+ goto out;
+
+ __page_init_poisoning = false;
+ if (*str == '-')
+ goto out;
+
+ while (*str) {
+ switch (tolower(*str)) {
+ case'p':
+ __page_init_poisoning = true;
+ break;
+ default:
+ pr_err("vm_debug option '%c' unknown. skipped\n",
+ *str);
+ }
+
+ str++;
+ }
+out:
+ if (page_init_poisoning && !__page_init_poisoning)
+ pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
+
+ page_init_poisoning = __page_init_poisoning;
+
+ return 1;
+}
+__setup("vm_debug", setup_vm_debug);
+
+void page_init_poison(struct page *page, size_t size)
+{
+ if (page_init_poisoning)
+ memset(page, PAGE_POISON_PATTERN, size);
+}
+EXPORT_SYMBOL_GPL(page_init_poison);
#endif /* CONFIG_DEBUG_VM */
--
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