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[Qemu-devel] [PATCH 19/66] memory: destroy phys_sections one by one
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 19/66] memory: destroy phys_sections one by one |
Date: |
Thu, 4 Jul 2013 17:13:15 +0200 |
phys_sections_clear is invoked after the dispatch tree has been
destroyed. This leaves a window where phys_sections_nb > 0 but the
subpages are not valid anymore, which is a recipe for use-after-free
bugs.
Move the destruction of subpages in phys_sections_clear. We will
still destroy the subpages when an address space is cleaned up,
because address_space_destroy will clear as->root and commit the
change before it calls address_space_destroy_dispatch.
Signed-off-by: Paolo Bonzini <address@hidden>
---
exec.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/exec.c b/exec.c
index 5094746..78be4f5 100644
--- a/exec.c
+++ b/exec.c
@@ -754,17 +754,6 @@ hwaddr memory_region_section_get_iotlb(CPUArchState *env,
static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
uint16_t section);
static subpage_t *subpage_init(AddressSpace *as, hwaddr base);
-static void destroy_page_desc(uint16_t section_index)
-{
- MemoryRegionSection *section = &phys_sections[section_index];
- MemoryRegion *mr = section->mr;
-
- if (mr->subpage) {
- subpage_t *subpage = container_of(mr, subpage_t, iomem);
- memory_region_destroy(&subpage->iomem);
- g_free(subpage);
- }
-}
static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
{
@@ -779,8 +768,6 @@ static void destroy_l2_mapping(PhysPageEntry *lp, unsigned
level)
for (i = 0; i < L2_SIZE; ++i) {
if (!p[i].is_leaf) {
destroy_l2_mapping(&p[i], level - 1);
- } else {
- destroy_page_desc(p[i].ptr);
}
}
lp->is_leaf = 0;
@@ -810,9 +797,21 @@ static uint16_t phys_section_add(MemoryRegionSection
*section)
return phys_sections_nb++;
}
+static void phys_section_destroy(MemoryRegion *mr)
+{
+ if (mr->subpage) {
+ subpage_t *subpage = container_of(mr, subpage_t, iomem);
+ memory_region_destroy(&subpage->iomem);
+ g_free(subpage);
+ }
+}
+
static void phys_sections_clear(void)
{
- phys_sections_nb = 0;
+ while (phys_sections_nb > 0) {
+ MemoryRegionSection *section = &phys_sections[--phys_sections_nb];
+ phys_section_destroy(section->mr);
+ }
}
static void register_subpage(AddressSpaceDispatch *d, MemoryRegionSection
*section)
--
1.8.1.4
- [Qemu-devel] [PATCH 08/66] prep: replace register_ioport*, (continued)
- [Qemu-devel] [PATCH 08/66] prep: replace register_ioport*, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 09/66] vt82c686: replace register_ioport*, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 10/66] Privatize register_ioport_read/write, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 11/66] isa: implement isa_is_ioport_assigned via memory_region_find, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 12/66] vmware-vga: Accept unaligned I/O accesses, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 13/66] xen: Mark fixed platform I/O as unaligned, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 14/66] ioport: Switch dispatching to memory core layer, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 16/66] vmport: Disentangle read handler type from portio, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 15/66] ioport: Remove unused old dispatching services, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 17/66] ioport: Move portio types to ioport.h, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 19/66] memory: destroy phys_sections one by one,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 20/66] exec: simplify destruction of the phys map, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 21/66] memory: add getter for owner, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 22/66] memory: add ref/unref, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 23/66] memory: introduce memory_region_present, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 24/66] memory: add ref/unref calls, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 25/66] exec: check MRU in qemu_ram_addr_from_host, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 26/66] exec: move qemu_ram_addr_from_host_nofail to cputlb.c, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 27/66] memory: return MemoryRegion from qemu_ram_addr_from_host, Paolo Bonzini, 2013/07/04
- [Qemu-devel] [PATCH 28/66] exec: reorganize address_space_map, Paolo Bonzini, 2013/07/04