[Qemu-devel] [PATCH] memory: check write/read_with_attrs in memory dispatch

[Li Qiang <liq3ea@gmail.com>]

This can avoid the NULL-deref if the rm doesn't has a
read/write nor write/read_with_attrs callback.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
---
 memory.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/memory.c b/memory.c
index d14c6dec1d..3baf5857b9 100644
--- a/memory.c
+++ b/memory.c
@@ -1377,13 +1377,15 @@ static MemTxResult memory_region_dispatch_read1(MemoryRegion *mr,
                                          mr->ops->impl.max_access_size,
                                          memory_region_read_accessor,
                                          mr, attrs);
-    } else {
+    } else if (mr->ops->read_with_attrs) {
         return access_with_adjusted_size(addr, pval, size,
                                          mr->ops->impl.min_access_size,
                                          mr->ops->impl.max_access_size,
                                          memory_region_read_with_attrs_accessor,
                                          mr, attrs);
     }
+
+    return MEMTX_DECODE_ERROR;
 }
 
 MemTxResult memory_region_dispatch_read(MemoryRegion *mr,
@@ -1454,7 +1456,7 @@ MemTxResult memory_region_dispatch_write(MemoryRegion *mr,
                                          mr->ops->impl.max_access_size,
                                          memory_region_write_accessor, mr,
                                          attrs);
-    } else {
+    } else if (mr->ops->write_with_attrs) {
         return
             access_with_adjusted_size(addr, &data, size,
                                       mr->ops->impl.min_access_size,
@@ -1462,6 +1464,8 @@ MemTxResult memory_region_dispatch_write(MemoryRegion *mr,
                                       memory_region_write_with_attrs_accessor,
                                       mr, attrs);
     }
+
+    return MEMTX_DECODE_ERROR;
 }
 
 void memory_region_init_io(MemoryRegion *mr,
-- 
2.11.0