FAILED: patch "[PATCH] mm/swapfile: fix wrong swap entry type for hwpoisoned" failed to apply to 6.4-stable tree

The patch below does not apply to the 6.4-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]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.4.y
git checkout FETCH_HEAD
git cherry-pick -x f985fc322063c73916a0d5b6b3fcc6db2ba5792c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023081243-component-eatery-a09a@gregkh' --subject-prefix 'PATCH 6.4.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From f985fc322063c73916a0d5b6b3fcc6db2ba5792c Mon Sep 17 00:00:00 2001
From: Miaohe Lin <[email protected]>
Date: Thu, 27 Jul 2023 19:56:40 +0800
Subject: [PATCH] mm/swapfile: fix wrong swap entry type for hwpoisoned
swapcache page

Patch series "A few fixup patches for mm", v2.

This series contains a few fixup patches to fix potential unexpected return value, fix wrong swap entry type for hwpoisoned swapcache page and so on. More details can be found in the respective changelogs.

This patch (of 3):

Hwpoisoned dirty swap cache page is kept in the swap cache and there's simple interception code in do_swap_page() to catch it. But when trying to swapoff, unuse_pte() will wrongly install a general sense of "future accesses are invalid" swap entry for hwpoisoned swap cache page due to unaware of such type of page. The user will receive SIGBUS signal without expected BUS_MCEERR_AR payload. BTW, typo 'hwposioned' is fixed.

index ba266359da55..d20d7662419b 100644
@@ -2784,6 +2784,8 @@ struct page *ksm_might_need_to_copy(struct page *page,
 			anon_vma->root == vma->anon_vma->root) {
 		return page;		/* still no need to copy it */
 	}
+	if (PageHWPoison(page))
+		return ERR_PTR(-EHWPOISON);
 	if (!PageUptodate(page))
 		return page;		/* let do_swap_page report the error */
 

index 8e6dde68b389..b15112b1f1a8 100644
@@ -1746,7 +1746,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 	struct page *swapcache;
 	spinlock_t *ptl;
 	pte_t *pte, new_pte, old_pte;
-	bool hwposioned = false;
+	bool hwpoisoned = PageHWPoison(page);
 	int ret = 1;
 
 	swapcache = page;

@@ -1754,7 +1754,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 	if (unlikely(!page))
 		return -ENOMEM;
 	else if (unlikely(PTR_ERR(page) == -EHWPOISON))
-		hwposioned = true;
+		hwpoisoned = true;
 
 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 	if (unlikely(!pte || !pte_same_as_swp(ptep_get(pte),

@@ -1765,11 +1765,11 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 
 	old_pte = ptep_get(pte);
 
-	if (unlikely(hwposioned || !PageUptodate(page))) {
+	if (unlikely(hwpoisoned || !PageUptodate(page))) {
 		swp_entry_t swp_entry;
 
 		dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
-		if (hwposioned) {
+		if (hwpoisoned) {
 			swp_entry = make_hwpoison_entry(swapcache);
 			page = swapcache;
 		} else {