[merged mm-hotfixes-stable] filemap-replace-pte_offset_map-with-pte_offset_map_nolock.patch removed from -mm tree

[merged mm-hotfixes-stable] filemap-replace-pte_offset_map-with-pte_offset_map_nolock.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: filemap: replace pte_offset_map() with pte_offset_map_nolock()
has been removed from the -mm tree.  Its filename was
     filemap-replace-pte_offset_map-with-pte_offset_map_nolock.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: ZhangPeng <zhangpeng362@huawei.com>
Subject: filemap: replace pte_offset_map() with pte_offset_map_nolock()
Date: Wed, 13 Mar 2024 09:29:13 +0800

The vmf->ptl in filemap_fault_recheck_pte_none() is still set from
handle_pte_fault().  But at the same time, we did a pte_unmap(vmf->pte). 
After a pte_unmap(vmf->pte) unmap and rcu_read_unlock(), the page table
may be racily changed and vmf->ptl maybe fails to protect the actual page
table.  Fix this by replacing pte_offset_map() with
pte_offset_map_nolock().

As David said, the PTL pointer might be stale so if we continue to use
it infilemap_fault_recheck_pte_none(), it might trigger UAF.  Also, if
the PTL fails, the issue fixed by commit 58f327f2ce80 ("filemap: avoid
unnecessary major faults in filemap_fault()") might reappear.

Link: https://lkml.kernel.org/r/20240313012913.2395414-1-zhangpeng362@huawei.com
Fixes: 58f327f2ce80 ("filemap: avoid unnecessary major faults in filemap_fault()")
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/filemap.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/filemap.c~filemap-replace-pte_offset_map-with-pte_offset_map_nolock
+++ a/mm/filemap.c
@@ -3231,7 +3231,8 @@ static vm_fault_t filemap_fault_recheck_
 	if (!(vmf->flags & FAULT_FLAG_ORIG_PTE_VALID))
 		return 0;
 
-	ptep = pte_offset_map(vmf->pmd, vmf->address);
+	ptep = pte_offset_map_nolock(vma->vm_mm, vmf->pmd, vmf->address,
+				     &vmf->ptl);
 	if (unlikely(!ptep))
 		return VM_FAULT_NOPAGE;
 
_

Patches currently in -mm which might be from zhangpeng362@huawei.com are