[PATCH v2 1/3] mm: lock a vma before stack expansion
From: Suren Baghdasaryan <surenb@google.com>
Date: 2023-07-08 19:12:22
Also in:
linux-mm, linuxppc-dev, lkml, regressions, stable
Subsystem:
memory management, memory mapping, the rest · Maintainers:
Andrew Morton, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
With recent changes necessitating mmap_lock to be held for write while expanding a stack, per-VMA locks should follow the same rules and be write-locked to prevent page faults into the VMA being expanded. Add the necessary locking. Cc: stable@vger.kernel.org Signed-off-by: Suren Baghdasaryan <surenb@google.com> --- mm/mmap.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/mm/mmap.c b/mm/mmap.c
index 204ddcd52625..c66e4622a557 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -1977,6 +1977,8 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address) return -ENOMEM; } + /* Lock the VMA before expanding to prevent concurrent page faults */ + vma_start_write(vma); /* * vma->vm_start/vm_end cannot change under us because the caller * is required to hold the mmap_lock in read mode. We need the
@@ -2064,6 +2066,8 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) return -ENOMEM; } + /* Lock the VMA before expanding to prevent concurrent page faults */ + vma_start_write(vma); /* * vma->vm_start/vm_end cannot change under us because the caller * is required to hold the mmap_lock in read mode. We need the
--
2.41.0.390.g38632f3daf-goog
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