hugetlbfs: don't delete error page from pagecache
authorJames Houghton <jthoughton@google.com>
Tue, 18 Oct 2022 20:01:25 +0000 (20:01 +0000)
committerAndrew Morton <akpm@linux-foundation.org>
Tue, 8 Nov 2022 23:57:22 +0000 (15:57 -0800)
commit8625147cafaa9ba74713d682f5185eb62cb2aedb
tree185342d7d161810419b46382581893ad93e46a22
parent120b116208a0877227fc82e3f0df81e7a3ed4ab1
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/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>
fs/hugetlbfs/inode.c
mm/hugetlb.c
mm/memory-failure.c