[PULL,1/3] memory: Make memory_region_readd_subregion() properly handle mapped aliases

Commit Message

Philippe Mathieu-Daudé March 29, 2022, 10:36 a.m. UTC

From: David Hildenbrand <[e-mail]>

memory_region_readd_subregion() wants to readd a region by first
removing it and then readding it. For readding, it doesn't use one of
the memory_region_add_*() variants, which is why fail to re-increment the
mr->mapped_via_alias counters, resulting in the
assert(alias->mapped_via_alias >= 0) in memory_region_del_subregion()
triggering the next time we call memory_region_readd_subregion().

Fix it by using memory_region_add_subregion_common() for readding the
region.

Reported-by: Niek Linnenbank <[e-mail]>
Fixes: 5ead62185d23 ("memory: Make memory_region_is_mapped() succeed when mapped via an alias")
Tested-by: Niek Linnenbank <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Cc: Peter Xu <[e-mail]>
Cc: "Philippe Mathieu-Daudé" <[e-mail]>
Signed-off-by: David Hildenbrand <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 softmmu/memory.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Patch

diff --git a/softmmu/memory.c b/softmmu/memory.c
index 8060c6de78..bfa5d5178c 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -2626,8 +2626,7 @@  static void memory_region_readd_subregion(MemoryRegion *mr)
         memory_region_transaction_begin();
         memory_region_ref(mr);
         memory_region_del_subregion(container, mr);
-        mr->container = container;
-        memory_region_update_container_subregions(mr);
+        memory_region_add_subregion_common(container, mr->addr, mr);
         memory_region_unref(mr);
         memory_region_transaction_commit();
     }