On 8/19/20 11:57 AM, Matthew Wilcox (Oracle) wrote:
We check i_dentry is fetchable and i_ino is earlier in the struct
than i_ino, so it ought to work fine, but it's possible that struct
randomisation has reordered i_ino after i_dentry and the pointer is
just wild enough that i_dentry is fetchable and i_ino isn't.
Also print the inode number if the dentry is invalid.
Reported-by: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/debug.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
It's hard to write software that reports what's wrong with
itself. Let's just keep adding to the pile, then. :)
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
thanks,
--
John Hubbard
NVIDIA
diff --git a/mm/debug.c b/mm/debug.c
index ca8d1cacdecc..2a767865145c 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -120,6 +120,7 @@ void __dump_page(struct page *page, const char *reason)
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
@@ -136,21 +137,22 @@ void __dump_page(struct page *page, const char *reason)
goto out_mapping;
}
- if (get_kernel_nofault(dentry_first, &host->i_dentry.first)) {
+ 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, host->i_ino);
+ 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 with invalid dentry %px\n", a_ops,
- 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
@@ -158,7 +160,7 @@ void __dump_page(struct page *page, const char *reason)
* corrupted struct page
*/
pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
- a_ops, host->i_ino, &dentry);
+ a_ops, ino, &dentry);
}
}
out_mapping:
