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[Qemu-devel] [PATCH] exec.c: Don't reallocate IOMMUNotifiers that are in
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH] exec.c: Don't reallocate IOMMUNotifiers that are in use |
Date: |
Mon, 28 Jan 2019 17:42:41 +0000 |
The tcg_register_iommu_notifier() code has a GArray of
TCGIOMMUNotifier structs which it has registered by passing
memory_region_register_iommu_notifier() a pointer to the embedded
IOMMUNotifier field. Unfortunately, if we need to enlarge the
array via g_array_set_size() this can cause a realloc(), which
invalidates the pointer that memory_region_register_iommu_notifier()
put into the MemoryRegion's iommu_notify list. This can result
in segfaults.
Switch the GArray to holding pointers to the TCGIOMMUNotifier
structs, so that we can individually allocate and free them.
Cc: address@hidden
Fixes: 1f871c5e6b0f30644a60a ("exec.c: Handle IOMMUs in
address_space_translate_for_iotlb()")
Signed-off-by: Peter Maydell <address@hidden>
---
I don't know why I've suddenly started running into this; possibly
it's because of a recent Ubuntu upgrade and so a newer glibc.
---
exec.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/exec.c b/exec.c
index 895449f9261..cf6bc72c976 100644
--- a/exec.c
+++ b/exec.c
@@ -665,7 +665,7 @@ static void tcg_register_iommu_notifier(CPUState *cpu,
int i;
for (i = 0; i < cpu->iommu_notifiers->len; i++) {
- notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i);
+ notifier = g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier *, i);
if (notifier->mr == mr && notifier->iommu_idx == iommu_idx) {
break;
}
@@ -673,7 +673,8 @@ static void tcg_register_iommu_notifier(CPUState *cpu,
if (i == cpu->iommu_notifiers->len) {
/* Not found, add a new entry at the end of the array */
cpu->iommu_notifiers = g_array_set_size(cpu->iommu_notifiers, i + 1);
- notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i);
+ notifier = g_new0(TCGIOMMUNotifier, 1);
+ g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier *, i) = notifier;
notifier->mr = mr;
notifier->iommu_idx = iommu_idx;
@@ -705,8 +706,9 @@ static void tcg_iommu_free_notifier_list(CPUState *cpu)
TCGIOMMUNotifier *notifier;
for (i = 0; i < cpu->iommu_notifiers->len; i++) {
- notifier = &g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier, i);
+ notifier = g_array_index(cpu->iommu_notifiers, TCGIOMMUNotifier *, i);
memory_region_unregister_iommu_notifier(notifier->mr, ¬ifier->n);
+ g_free(notifier);
}
g_array_free(cpu->iommu_notifiers, true);
}
@@ -976,7 +978,7 @@ void cpu_exec_realizefn(CPUState *cpu, Error **errp)
vmstate_register(NULL, cpu->cpu_index, cc->vmsd, cpu);
}
- cpu->iommu_notifiers = g_array_new(false, true, sizeof(TCGIOMMUNotifier));
+ cpu->iommu_notifiers = g_array_new(false, true, sizeof(TCGIOMMUNotifier
*));
#endif
}
--
2.20.1
- [Qemu-devel] [PATCH] exec.c: Don't reallocate IOMMUNotifiers that are in use,
Peter Maydell <=