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[Qemu-devel] [PATCH] exec.c: Use atomic_rcu_read() to access dispatch in
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH] exec.c: Use atomic_rcu_read() to access dispatch in memory_region_section_get_iotlb() |
Date: |
Mon, 20 Jul 2015 12:27:16 +0100 |
When accessing the dispatch pointer in an AddressSpace within an RCU
critical section we should always use atomic_rcu_read(). Fix an
access within memory_region_section_get_iotlb() which was incorrectly
doing a direct pointer access.
Signed-off-by: Peter Maydell <address@hidden>
---
I discussed this on IRC with Paolo a while back, and IIRC he said
that although this is a bug it's not one that can currently have
any ill effects, though I forget why (probably because this code
path is TCG only and TCG is single-threaded right now).
exec.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index 7d60e15..0a4a0c5 100644
--- a/exec.c
+++ b/exec.c
@@ -954,7 +954,10 @@ hwaddr memory_region_section_get_iotlb(CPUState *cpu,
iotlb |= PHYS_SECTION_ROM;
}
} else {
- iotlb = section - section->address_space->dispatch->map.sections;
+ AddressSpaceDispatch *d;
+
+ d = atomic_rcu_read(§ion->address_space->dispatch);
+ iotlb = section - d->map.sections;
iotlb += xlat;
}
--
1.9.1
- [Qemu-devel] [PATCH] exec.c: Use atomic_rcu_read() to access dispatch in memory_region_section_get_iotlb(),
Peter Maydell <=