@@ -318,6 +318,13 @@ int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb)
rc = make_folio_secure(folio, uvcb);
folio_unlock(folio);
}
+
+ /*
+ * Once we drop the PTL, the folio may get unmapped and
+ * freed immediately. We need a temporary reference.
+ */
+ if (rc == -EAGAIN)
+ folio_get(folio);
}
unlock:
pte_unmap_unlock(ptep, ptelock);
@@ -330,6 +337,7 @@ int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb)
* completion, this is just a useless check, but it is safe.
*/
folio_wait_writeback(folio);
+ folio_put(folio);
} else if (rc == -EBUSY) {
/*
* If we have tried a local drain and the folio refcount
folio_wait_writeback() requires that no spinlocks are held and that a folio reference is held, as documented. After we dropped the PTL, the folio could get freed concurrently. So grab a temporary reference. Fixes: 214d9bbcd3a6 ("s390/mm: provide memory management functions for protected KVM guests") Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: David Hildenbrand <david@redhat.com> --- arch/s390/kernel/uv.c | 8 ++++++++ 1 file changed, 8 insertions(+)