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[NTOS:MM] Fix a race

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This commit is contained in:
Jérôme Gardou 2020-12-30 09:43:55 +01:00
parent 11eee4eeec
commit 8ed15a49a7
2 changed files with 32 additions and 2 deletions
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7
ntoskrnl/mm/freelist.c
View file

@ -436,7 +436,12 @@ MmGetRmapListHeadPage(PFN_NUMBER Pfn)
/* Get the entry */
Pfn1 = MiGetPfnEntry(Pfn);
ASSERT(Pfn1);
ASSERT_IS_ROS_PFN(Pfn1);
if (!MI_IS_ROS_PFN(Pfn1))
{
MiReleasePfnLock(oldIrql);
return NULL;
}
/* Get the list head */
ListHead = Pfn1->RmapListHead;

27
ntoskrnl/mm/rmap.c
View file

@ -149,7 +149,32 @@ MmPageOutPhysicalAddress(PFN_NUMBER Page)
/* Delete this virtual mapping in the process */
MmDeleteVirtualMapping(Process, Address, &Dirty, &MapPage);
ASSERT(MapPage == Page);
/* There is a window betwwen the start of this function and now,
* where it's possible that the process changed its memory layout,
* because of copy-on-write, unmapping memory, or whatsoever.
* Just go away if that is the case */
if (MapPage != Page)
{
PMM_REGION Region = MmFindRegion((PVOID)MA_GetStartingAddress(MemoryArea),
&MemoryArea->SectionData.RegionListHead,
Address, NULL);
/* Restore the mapping */
MmCreateVirtualMapping(Process, Address, Region->Protect, &MapPage, 1);
if (Dirty)
MmSetDirtyPage(Process, Address);
MmUnlockSectionSegment(Segment);
MmUnlockAddressSpace(AddressSpace);
if (Address < MmSystemRangeStart)
{
ExReleaseRundownProtection(&Process->RundownProtect);
ObDereferenceObject(Process);
}
/* We can still try to flush it to disk, though */
goto WriteSegment;
}
if (Page != PFN_FROM_SSE(Entry))
{