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hugetlbfs: don't delete error page from pagecache

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[ Upstream commit 8625147caf ]

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 a760542666 ("mm: shmem: don't truncate page if memory failure happens")

Link: https://lkml.kernel.org/r/20221018200125.848471-1-jthoughton@google.com
Signed-off-by: James Houghton <jthoughton@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Tested-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
James Houghton 2022-10-18 20:01:25 +00:00 • committed by Justin Hammond
parent 8ac32285ea
commit 220dae6595
3 changed files with 14 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
fs/hugetlbfs/inode.c
View file

@ -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;
}

4
mm/hugetlb.c
View file

@ -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

5
mm/memory-failure.c
View file

@ -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;