From 3e9d80a891df3b1a5d77db47fa7fdf33ba71e5cb Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Fri, 14 Jan 2022 14:05:04 -0800
Subject: [PATCH] mm,fs: split dump_mapping() out from dump_page()
dump_mapping() is a big chunk of dump_page(), and it'd be handy to be
able to call it when we don't have a struct page. Split it out and move
it to fs/inode.c. Take the opportunity to simplify some of the debug
messages a little.
Link: https://lkml.kernel.org/r/20211121121056.2870061-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/inode.c | 49 +++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 1 +
mm/debug.c | 52 ++--------------------------------------------
3 files changed, 52 insertions(+), 50 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 6b80a51129d56..980e7b7a54607 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -526,6 +526,55 @@ void __remove_inode_hash(struct inode *inode)
}
EXPORT_SYMBOL(__remove_inode_hash);
+void dump_mapping(const struct address_space *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;
+
+ /*
+ * If mapping is an invalid pointer, 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("invalid mapping:%px\n", mapping);
+ return;
+ }
+
+ if (!host) {
+ pr_warn("aops:%ps\n", a_ops);
+ return;
+ }
+
+ if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
+ get_kernel_nofault(ino, &host->i_ino)) {
+ pr_warn("aops:%ps invalid inode:%px\n", a_ops, host);
+ return;
+ }
+
+ if (!dentry_first) {
+ pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
+ return;
+ }
+
+ 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 invalid dentry:%px\n",
+ a_ops, ino, dentry_ptr);
+ return;
+ }
+
+ /*
+ * if dentry is corrupted, the %pd handler may still crash,
+ * but it's unlikely that we reach here with a corrupt mapping
+ */
+ pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry);
+}
+
void clear_inode(struct inode *inode)
{
/*
diff --git a/include/linux/fs.h b/include/linux/fs.h
index bbf812ce89a8c..5315fa68f751a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3152,6 +3152,7 @@ extern void unlock_new_inode(struct inode *);
extern void discard_new_inode(struct inode *);
extern unsigned int get_next_ino(void);
extern void evict_inodes(struct super_block *sb);
+void dump_mapping(const struct address_space *);
/*
* Userspace may rely on the the inode number being non-zero. For example, glibc
diff --git a/mm/debug.c b/mm/debug.c
index a05a39ff8fe4f..bc9ac87f0e08d 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -112,56 +112,8 @@ static void __dump_page(struct page *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:
+ else if (mapping)
+ dump_mapping(mapping);
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
pr_warn("%sflags: %pGp%s\n", type, &head->flags,
--
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