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authorTakashi Iwai <tiwai@suse.de>2023-08-24 09:27:21 +0200
committerTakashi Iwai <tiwai@suse.de>2023-08-24 09:27:21 +0200
commita057efde80453c68c60e156803578a654b52c39f (patch)
tree51c312e95de536b6a29d18a12cfdba72029e09ad /mm/memory.c
parent17a1eab7b70d85fc5711f37bb6e530b771736bb7 (diff)
parenta4a6eed851bb661477654d772807d0e5aee5629c (diff)
Merge branch 'for-linus' into for-next
Back-merge the 6.5-devel branch for the clean patch application for 6.6 and resolving merge conflicts. Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c28
1 files changed, 16 insertions, 12 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 01f39e8144eff..603b2f4199483 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5393,27 +5393,28 @@ retry:
if (!vma_is_anonymous(vma) && !vma_is_tcp(vma))
goto inval;
- /* find_mergeable_anon_vma uses adjacent vmas which are not locked */
- if (!vma->anon_vma && !vma_is_tcp(vma))
- goto inval;
-
if (!vma_start_read(vma))
goto inval;
/*
+ * find_mergeable_anon_vma uses adjacent vmas which are not locked.
+ * This check must happen after vma_start_read(); otherwise, a
+ * concurrent mremap() with MREMAP_DONTUNMAP could dissociate the VMA
+ * from its anon_vma.
+ */
+ if (unlikely(!vma->anon_vma && !vma_is_tcp(vma)))
+ goto inval_end_read;
+
+ /*
* Due to the possibility of userfault handler dropping mmap_lock, avoid
* it for now and fall back to page fault handling under mmap_lock.
*/
- if (userfaultfd_armed(vma)) {
- vma_end_read(vma);
- goto inval;
- }
+ if (userfaultfd_armed(vma))
+ goto inval_end_read;
/* Check since vm_start/vm_end might change before we lock the VMA */
- if (unlikely(address < vma->vm_start || address >= vma->vm_end)) {
- vma_end_read(vma);
- goto inval;
- }
+ if (unlikely(address < vma->vm_start || address >= vma->vm_end))
+ goto inval_end_read;
/* Check if the VMA got isolated after we found it */
if (vma->detached) {
@@ -5425,6 +5426,9 @@ retry:
rcu_read_unlock();
return vma;
+
+inval_end_read:
+ vma_end_read(vma);
inval:
rcu_read_unlock();
count_vm_vma_lock_event(VMA_LOCK_ABORT);