On 11/14/22 11:33, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 6.0-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
Below is backport for 6.0-stable. Only minor conflicts in code that is being
removed by this patch. Tested with simple program to access hugetlb pagecache
page after poisoning.
>From 5dcd97ae1a0848c1b9a1ec5f4ab623b1ab478892 Mon Sep 17 00:00:00 2001
From: James Houghton <jthoughton@xxxxxxxxxx>
Date: Tue, 18 Oct 2022 20:01:25 +0000
Subject: [PATCH] hugetlbfs: don't delete error page from pagecache
commit 8625147cafaa9ba74713d682f5185eb62cb2aedb upstream.
This change is very similar to the change that was made for shmem [1], and
it solves the same problem but for HugeTLBFS instead.
Currently, when poison is found in a HugeTLB page, the page is removed
from the page cache. That means that attempting to map or read that
hugepage in the future will result in a new hugepage being allocated
instead of notifying the user that the page was poisoned. As [1] states,
this is effectively memory corruption.
The fix is to leave the page in the page cache. If the user attempts to
use a poisoned HugeTLB page with a syscall, the syscall will fail with
EIO, the same error code that shmem uses. For attempts to map the page,
the thread will get a BUS_MCEERR_AR SIGBUS.
[1]: commit a76054266661 ("mm: shmem: don't truncate page if memory failure happens")
Link: https://lkml.kernel.org/r/20221018200125.848471-1-jthoughton@xxxxxxxxxx
Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Tested-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: James Houghton <jthoughton@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 13 ++++++-------
mm/hugetlb.c | 4 ++++
mm/memory-failure.c | 5 ++++-
3 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index f7a5b5124d8a..398f8702c34f 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -328,6 +328,12 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
} else {
unlock_page(page);
+ if (PageHWPoison(page)) {
+ put_page(page);
+ retval = -EIO;
+ break;
+ }
+
/*
* We have the page, copy it to user space buffer.
*/
@@ -991,13 +997,6 @@ static int hugetlbfs_migrate_folio(struct address_space *mapping,
static int hugetlbfs_error_remove_page(struct address_space *mapping,
struct page *page)
{
- struct inode *inode = mapping->host;
- pgoff_t index = page->index;
-
- remove_huge_page(page);
- if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
- hugetlb_fix_reserve_counts(inode);
-
return 0;
}
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ecc197d24efb..590ba2bf033d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6021,6 +6021,10 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
spin_lock(ptl);
+ ret = -EIO;
+ if (PageHWPoison(page))
+ goto out_release_unlock;
+
/*
* Recheck the i_size after holding PT lock to make sure not
* to leave any page mapped (as page_mapped()) beyond the end
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e7ac570dda75..4d302f6b02fc 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1079,6 +1079,7 @@ static int me_huge_page(struct page_state *ps, struct page *p)
int res;
struct page *hpage = compound_head(p);
struct address_space *mapping;
+ bool extra_pins = false;
if (!PageHuge(hpage))
return MF_DELAYED;
@@ -1086,6 +1087,8 @@ static int me_huge_page(struct page_state *ps, struct page *p)
mapping = page_mapping(hpage);
if (mapping) {
res = truncate_error_page(hpage, page_to_pfn(p), mapping);
+ /* The page is kept in page cache. */
+ extra_pins = true;
unlock_page(hpage);
} else {
unlock_page(hpage);
@@ -1103,7 +1106,7 @@ static int me_huge_page(struct page_state *ps, struct page *p)
}
}
- if (has_extra_refcount(ps, p, false))
+ if (has_extra_refcount(ps, p, extra_pins))
res = MF_FAILED;
return res;
--
2.38.1
