This is a note to let you know that I've just added the patch titled
hugetlbfs: don't delete error page from pagecache
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hugetlbfs-don-t-delete-error-page-from-pagecache.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0a2add122582bf84c10561cad33fe3b36c1e4209
Author: James Houghton <jthoughton@xxxxxxxxxx>
Date: Tue Oct 18 20:01:25 2022 +0000
hugetlbfs: don't delete error page from pagecache
[ Upstream commit 8625147cafaa9ba74713d682f5185eb62cb2aedb ]
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: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index d74a49b188c2..be8deec29ebe 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -361,6 +361,12 @@ 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.
*/
@@ -984,13 +990,6 @@ static int hugetlbfs_migrate_page(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 dbb63ec3b5fa..e7bd42f23667 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5350,6 +5350,10 @@ 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 85b1a77e3a99..2ad0f4580091 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1040,6 +1040,7 @@ 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;
@@ -1047,6 +1048,8 @@ 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 {
res = MF_FAILED;
@@ -1064,7 +1067,7 @@ 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;
