[PATCH v2 26/33] mm: prevent do_swap_page from handling page faults under VMA lock
Suren Baghdasaryan
surenb at google.com
Fri Jan 27 11:41:03 PST 2023
Due to the possibility of do_swap_page dropping mmap_lock, abort fault
handling under VMA lock and retry holding mmap_lock. This can be handled
more gracefully in the future.
Signed-off-by: Suren Baghdasaryan <surenb at google.com>
Reviewed-by: Laurent Dufour <laurent.dufour at fr.ibm.com>
---
mm/memory.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/mm/memory.c b/mm/memory.c
index 593548f24007..33ecc850d3cb 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3690,6 +3690,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
if (!pte_unmap_same(vmf))
goto out;
+ if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
+ ret = VM_FAULT_RETRY;
+ goto out;
+ }
+
entry = pte_to_swp_entry(vmf->orig_pte);
if (unlikely(non_swap_entry(entry))) {
if (is_migration_entry(entry)) {
--
2.39.1
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