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authorSuren Baghdasaryan <surenb@google.com>2023-07-08 12:12:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-07-08 14:08:02 -0700
commitc137381f71aec755fbf47cd4e9bd4dce752c054c (patch)
tree13f8dc7926e331b638e943a6759f9be7c87b7484 /mm
parent7fcd473a6455450428795d20db7afd2691c92336 (diff)
mm: lock a vma before stack expansion
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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c4
1 files changed, 4 insertions, 0 deletions
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