From: Kairui Song <kasong@xxxxxxxxxxx>
When swapoff race with swapin, get_swap_device may fail and cause
swapin_readahead to return -EBUSY. In such case check if the page is
already swapped in by swapoff path.
Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
---
mm/memory.c | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index e399b37ef395..620fa87557fd 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3846,9 +3846,21 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
vmf, &cache_result);
- if (PTR_ERR(page) == -EBUSY) {
- goto out;
- } else if (page) {
+ if (IS_ERR_OR_NULL(page)) {
+ /*
+ * Back out if somebody else faulted in this pte
+ * while we released the pte lock.
+ */
+ vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
+ vmf->address, &vmf->ptl);
+ if (likely(vmf->pte && pte_same(ptep_get(vmf->pte), vmf->orig_pte))) {
+ if (!page)
+ ret = VM_FAULT_OOM;
+ else
+ ret = VM_FAULT_RETRY;
+ }
+ goto unlock;
+ } else {
folio = page_folio(page);
if (cache_result != SWAP_CACHE_HIT) {
/* Had to read the page from swap area: Major fault */
@@ -3866,17 +3878,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
ret = VM_FAULT_HWPOISON;
goto out_release;
}
- } else {
- /*
- * Back out if somebody else faulted in this pte
- * while we released the pte lock.
- */
- vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
- vmf->address, &vmf->ptl);
- if (likely(vmf->pte &&
- pte_same(ptep_get(vmf->pte), vmf->orig_pte)))
- ret = VM_FAULT_OOM;
- goto unlock;
}
ret |= folio_lock_or_retry(folio, vmf);
--
2.42.0
