mm: support poison recovery from do_cow_fault()

Patch series "mm: hwpoison: two more poison recovery".

One more CoW path to support poison recorvery in do_cow_fault(), and the
last copy_user_highpage() user is replaced to copy_mc_user_highpage() from
copy_present_page() during fork to support poison recorvery too.

This patch (of 2):

Like commit a873dfe1032a ("mm, hwpoison: try to recover from copy-on
write faults"), there is another path which could crash because it does
not have recovery code where poison is consumed by the kernel in
do_cow_fault(), a crash calltrace shown below on old kernel, but it
could be happened in the lastest mainline code,

  CPU: 7 PID: 3248 Comm: mpi Kdump: loaded Tainted: G           OE     5.10.0 #1
  pc : copy_page+0xc/0xbc
  lr : copy_user_highpage+0x50/0x9c
  Call trace:
    copy_page+0xc/0xbc
    do_cow_fault+0x118/0x2bc
    do_fault+0x40/0x1a4
    handle_pte_fault+0x154/0x230
    __handle_mm_fault+0x1a8/0x38c
    handle_mm_fault+0xf0/0x250
    do_page_fault+0x184/0x454
    do_translation_fault+0xac/0xd4
    do_mem_abort+0x44/0xbc

Fix it by using copy_mc_user_highpage() to handle this case and return
VM_FAULT_HWPOISON for cow fault.

[wangkefeng.wang@huawei.com: unlock/put vmf->page, per Miaohe]
Link: https://lkml.kernel.org/r/20240910021541.234300-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index 42674c0748cba87569da942f1a8ff5182c3c8c7e..64421ea5a403683f5851d2880c9d90f734a127ca 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5089,10 +5089,14 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
        if (ret & VM_FAULT_DONE_COW)
                return ret;
 
-       copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
+       if (copy_mc_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma)) {
+               ret = VM_FAULT_HWPOISON;
+               goto unlock;
+       }
        __folio_mark_uptodate(folio);
 
        ret |= finish_fault(vmf);
+unlock:
        unlock_page(vmf->page);
        put_page(vmf->page);
        if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))