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[Qemu-devel] [PATCH] memory: unregister AddressSpace MemoryListener with
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH] memory: unregister AddressSpace MemoryListener within BQL |
Date: |
Tue, 10 Feb 2015 13:52:49 +0100 |
address_space_destroy_dispatch is called from an RCU callback and hence
outside the iothread mutex (BQL). However, after address_space_destroy
no new accesses can hit the destroyed AddressSpace so it is not necessary
to observe changes to the memory map. Move the memory_listener_unregister
call earlier, to make it thread-safe again.
Reported-by: Alex Williamson <address@hidden>
Fixes: 374f2981d1f10bc4307f250f24b2a7ddb9b14be0
Signed-off-by: Paolo Bonzini <address@hidden>
---
exec.c | 6 +++++-
include/exec/memory-internal.h | 1 +
memory.c | 1 +
3 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index 6b79ad1..6dff7bc 100644
--- a/exec.c
+++ b/exec.c
@@ -2059,11 +2059,15 @@ void address_space_init_dispatch(AddressSpace *as)
memory_listener_register(&as->dispatch_listener, as);
}
+void address_space_unregister(AddressSpace *as)
+{
+ memory_listener_unregister(&as->dispatch_listener);
+}
+
void address_space_destroy_dispatch(AddressSpace *as)
{
AddressSpaceDispatch *d = as->dispatch;
- memory_listener_unregister(&as->dispatch_listener);
g_free(d);
as->dispatch = NULL;
}
diff --git a/include/exec/memory-internal.h b/include/exec/memory-internal.h
index 25c43c0..fb467ac 100644
--- a/include/exec/memory-internal.h
+++ b/include/exec/memory-internal.h
@@ -23,6 +23,7 @@
typedef struct AddressSpaceDispatch AddressSpaceDispatch;
void address_space_init_dispatch(AddressSpace *as);
+void address_space_unregister(AddressSpace *as);
void address_space_destroy_dispatch(AddressSpace *as);
extern const MemoryRegionOps unassigned_mem_ops;
diff --git a/memory.c b/memory.c
index 9b91243..130152c 100644
--- a/memory.c
+++ b/memory.c
@@ -1978,6 +1978,7 @@ void address_space_destroy(AddressSpace *as)
as->root = NULL;
memory_region_transaction_commit();
QTAILQ_REMOVE(&address_spaces, as, address_spaces_link);
+ address_space_unregister(as);
/* At this point, as->dispatch and as->current_map are dummy
* entries that the guest should never use. Wait for the old
--
1.8.3.1
- [Qemu-devel] [PATCH] memory: unregister AddressSpace MemoryListener within BQL,
Paolo Bonzini <=