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FAILED: patch "[PATCH] hugetlbfs: don't delete error page from pagecache" failed to apply to 6.0-stable tree

PATCH [email protected] 2 participants 3 messages Nov 14, 2022 – Nov 21, 2022

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Stable branch Memory management HugeTLB HWPoison memory failure handling
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[email protected]

author maintainer
#0 lore raw

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 <[email protected]>.

Possible dependencies:

8625147cafaa ("hugetlbfs: don't delete error page from pagecache") 7e1813d48dd3 ("hugetlb: rename remove_huge_page to hugetlb_delete_from_page_cache")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8625147cafaa9ba74713d682f5185eb62cb2aedb Mon Sep 17 00:00:00 2001
From: James Houghton <[email protected]>
Date: Tue, 18 Oct 2022 20:01:25 +0000
Subject: [PATCH] hugetlbfs: don't delete error page from pagecache

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/[email protected] open here
Signed-off-by James Houghton <[email protected]>
Reviewed-by Mike Kravetz <[email protected]>
Reviewed-by Naoya Horiguchi <[email protected]>
Tested-by Naoya Horiguchi <[email protected]>
Reviewed-by Yang Shi <[email protected]>
Cc Axel Rasmussen <[email protected]>
Cc James Houghton <[email protected]>
Cc Miaohe Lin <[email protected]>
Cc Muchun Song <[email protected]>
Cc <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
fs/hugetlbfs/inode.c +6 -7
index dd54f67e47fd..df7772335dc0 100644
@@ -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.
 			 */

@@ -1111,13 +1117,6 @@ 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;
-
-	hugetlb_delete_from_page_cache(page);
-	if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
-		hugetlb_fix_reserve_counts(inode);
-
 	return 0;
 }
mm/hugetlb.c +4 -0
index 546df97c31e4..e48f8ef45b17 100644
@@ -6111,6 +6111,10 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
 
 	ptl = huge_pte_lock(h, dst_mm, dst_pte);
 
+	ret = -EIO;
+	if (PageHWPoison(page))
+		goto out_release_unlock;
+
 	/*
 	 * We allow to overwrite a pte marker: consider when both MISSING|WP
 	 * registered, we firstly wr-protect a none pte which has no page cache
mm/memory-failure.c +4 -1
index 145bb561ddb3..bead6bccc7f2 100644
@@ -1080,6 +1080,7 @@ 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;

@@ -1087,6 +1088,8 @@ 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);

@@ -1104,7 +1107,7 @@ 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;
Reviewed-by Reviewed-by Naoya Horiguchi Tested-by Naoya Horiguchi Reviewed-by Yang Shi
#1 lore raw
Quoted 5 lines · On 11/14/22 11:33, [email protected] 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 <[email protected]>.

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 <[email protected]>
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/[email protected] open here
Signed-off-by James Houghton <[email protected]>
Reviewed-by Mike Kravetz <[email protected]>
Reviewed-by Naoya Horiguchi <[email protected]>
Tested-by Naoya Horiguchi <[email protected]>
Reviewed-by Yang Shi <[email protected]>
Cc Axel Rasmussen <[email protected]>
Cc James Houghton <[email protected]>
Cc Miaohe Lin <[email protected]>
Cc Muchun Song <[email protected]>
Cc <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Mike Kravetz <[email protected]>
---
 fs/hugetlbfs/inode.c | 13 ++++++-------
 mm/hugetlb.c         |  4 ++++
 mm/memory-failure.c  |  5 ++++-
 3 files changed, 14 insertions(+), 8 deletions(-)
fs/hugetlbfs/inode.c +6 -7
index f7a5b5124d8a..398f8702c34f 100644
@@ -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;
 }
mm/hugetlb.c +4 -0
index ecc197d24efb..590ba2bf033d 100644
@@ -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
mm/memory-failure.c +4 -1
index e7ac570dda75..4d302f6b02fc 100644
@@ -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;
Signature · 1 line
2.38.1
author maintainer
#2 lore raw
Quoted 7 lines · Mike Kravetz
Quoted 5 lines · On 11/14/22 11:33, [email protected] 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 <[email protected]>.

Quoted 8 lines

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.

Quoted 1 line

From 5dcd97ae1a0848c1b9a1ec5f4ab623b1ab478892 Mon Sep 17 00:00:00 2001

From: James Houghton <[email protected]>
Date: Tue, 18 Oct 2022 20:01:25 +0000
Subject: [PATCH] hugetlbfs: don't delete error page from pagecache

Looks like Sasha already picked this up, thanks.

greg k-h