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mm/swapfile: fix wrong swap entry type for hwpoisoned swapcache page 

commit f985fc322063c73916a0d5b6b3fcc6db2ba5792c
Author: Miaohe Lin <linmiaohe@huawei.com>
Date:   Thu Jul 27 19:56:40 2023 +0800

    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.

    Link: https://lkml.kernel.org/r/20230727115643.639741-1-linmiaohe@huawei.com
    Link: https://lkml.kernel.org/r/20230727115643.639741-2-linmiaohe@huawei.com
    Fixes: 6b970599e807 ("mm: hwpoison: support recovery from ksm_might_need_to_copy()")
    Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
    Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
    Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
    Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

JIRA: https://issues.redhat.com/browse/RHEL-5619
Signed-off-by: Nico Pache <npache@redhat.com>
This commit is contained in:
Nico Pache 2024-04-15 19:04:28 -06:00
parent 2435935842
commit 94afa740b8
2 changed files with 6 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
mm/ksm.c
View File

@ -2783,6 +2783,8 @@ 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 */

8
mm/swapfile.c
View File

@ -1764,7 +1764,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
struct page *swapcache;
spinlock_t *ptl;
pte_t *pte, new_pte;
bool hwposioned = false;
bool hwpoisoned = PageHWPoison(page);
int ret = 1;
swapcache = page;
@ -1772,7 +1772,7 @@ 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(*pte, swp_entry_to_pte(entry)))) {
@ -1780,11 +1780,11 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
goto out;
}
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 {