shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-05 10:31:46 +09:00
Code Issues Packages Projects Releases Wiki Activity

FROMGIT: userfaultfd: fix PTE unmapping stack-allocated PTE copies

Browse Source 
Current implementation of move_pages_pte() copies source and destination
PTEs in order to detect concurrent changes to PTEs involved in the move.
However these copies are also used to unmap the PTEs, which will fail if
CONFIG_HIGHPTE is enabled because the copies are allocated on the stack.
Fix this by using the actual PTEs which were kmap()ed.

Link: https://lkml.kernel.org/r/20250226185510.2732648-3-surenb@google.com
Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
(cherry-picked from commit 927e926d72d9155fde3264459fe9bfd7b5e40d28 https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-hotfixes-stable)
Change-Id: I0ee6c1b509ea7c4fa68056d6e512d4ac167c9234
Bug: 401790618
This commit is contained in:
Suren Baghdasaryan
2025-02-26 10:55:09 -08:00
committed by Lokesh Gidra
parent af439accc7
commit 8d8d44ff91
1 changed files with 10 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
mm/userfaultfd.c
View File

@@ -1175,8 +1175,8 @@ retry:
spin_unlock(src_ptl); spin_unlock(src_ptl);
if (!locked) { if (!locked) {
pte_unmap(&orig_src_pte); pte_unmap(src_pte);
pte_unmap(&orig_dst_pte); pte_unmap(dst_pte);
src_pte = dst_pte = NULL; src_pte = dst_pte = NULL;
/* now we can block and wait */ /* now we can block and wait */
folio_lock(src_folio); folio_lock(src_folio);
@@ -1192,8 +1192,8 @@ retry:
/* at this point we have src_folio locked */ /* at this point we have src_folio locked */
if (folio_test_large(src_folio)) { if (folio_test_large(src_folio)) {
/* split_folio() can block */ /* split_folio() can block */
pte_unmap(&orig_src_pte); pte_unmap(src_pte);
pte_unmap(&orig_dst_pte); pte_unmap(dst_pte);
src_pte = dst_pte = NULL; src_pte = dst_pte = NULL;
err = split_folio(src_folio); err = split_folio(src_folio);
if (err) if (err)
@@ -1218,8 +1218,8 @@ retry:
goto out; goto out;
} }
if (!anon_vma_trylock_write(src_anon_vma)) { if (!anon_vma_trylock_write(src_anon_vma)) {
pte_unmap(&orig_src_pte); pte_unmap(src_pte);
pte_unmap(&orig_dst_pte); pte_unmap(dst_pte);
src_pte = dst_pte = NULL; src_pte = dst_pte = NULL;
/* now we can block and wait */ /* now we can block and wait */
anon_vma_lock_write(src_anon_vma); anon_vma_lock_write(src_anon_vma);
@@ -1237,8 +1237,8 @@ retry:
entry = pte_to_swp_entry(orig_src_pte); entry = pte_to_swp_entry(orig_src_pte);
if (non_swap_entry(entry)) { if (non_swap_entry(entry)) {
if (is_migration_entry(entry)) { if (is_migration_entry(entry)) {
pte_unmap(&orig_src_pte); pte_unmap(src_pte);
pte_unmap(&orig_dst_pte); pte_unmap(dst_pte);
src_pte = dst_pte = NULL; src_pte = dst_pte = NULL;
migration_entry_wait(mm, src_pmd, src_addr); migration_entry_wait(mm, src_pmd, src_addr);
err = -EAGAIN; err = -EAGAIN;
@@ -1281,8 +1281,8 @@ retry:
src_folio = folio; src_folio = folio;
src_folio_pte = orig_src_pte; src_folio_pte = orig_src_pte;
if (!folio_trylock(src_folio)) { if (!folio_trylock(src_folio)) {
pte_unmap(&orig_src_pte); pte_unmap(src_pte);
pte_unmap(&orig_dst_pte); pte_unmap(dst_pte);
src_pte = dst_pte = NULL; src_pte = dst_pte = NULL;
put_swap_device(si); put_swap_device(si);
si = NULL; si = NULL;