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[NTOS]: Blimey this was a hard one. When using the reserved flag to request 1MB in a new process (which is used for starting SMSS and CSRSS), we must request 1MB - 256 bytes (or any number, actually) to offset the fact that with a base address of 0x4, a 1MB region gets us at 0x100FFF, and not 0xFFFF, because Windows computes ending address *before* alignment, and then returns a new region size for you (so if you pass in 1MB, you get 1MB + 4096KB). In Win32csr, when the code is trying to release 1MB, this ended up in our "Case A", because it would still leave a page in the VAD. Fixed rtl to request just shy off a MB. Verified on Windows as well.

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[NTOS]: The fix above was due to fixing "EndingAddress" which was being initialized to zero too late (after writing to it!). This caused allocations with a fixed base address that were already on top of another allocation not to be seen as a conflict, then we tried inserting a VAD and received an ASSERT saying we've already found a VAD there. After fixing the sizing code, the bug above creeped up.
Whoever wrote the NtFreeVirtualMemory test is a godsend. It has been nailing bug after bug in the VAD implementation. Thank you.

svn path=/trunk/; revision=55990
This commit is contained in:
Sir Richard 2012-03-04 06:42:49 +00:00
parent acb68dc20d
commit 83a2328786
2 changed files with 14 additions and 13 deletions
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2
reactos/lib/rtl/process.c
View file

@ -84,7 +84,7 @@ RtlpInitEnvironment(HANDLE ProcessHandle,
{
/* Give 1MB starting at 0x4 */
BaseAddress = (PVOID)4;
EnviroSize = 1024 * 1024;
EnviroSize = (1024 * 1024) - 256;
Status = ZwAllocateVirtualMemory(ProcessHandle,
&BaseAddress,
0,

25
reactos/ntoskrnl/mm/ARM3/virtual.c
View file

@ -3295,6 +3295,8 @@ NtAllocateVirtualMemory(IN HANDLE ProcessHandle,
//
PRegionSize = ROUND_TO_PAGES(PRegionSize);
PageCount = BYTES_TO_PAGES(PRegionSize);
EndingAddress = 0;
StartingAddress = 0;
}
else
{
@ -3336,7 +3338,6 @@ NtAllocateVirtualMemory(IN HANDLE ProcessHandle,
// which was passed in isn't already conflicting with an existing address
// range.
//
EndingAddress = 0;
if (!PBaseAddress)
{
Status = MiFindEmptyAddressRangeInTree(PRegionSize,
@ -3345,6 +3346,17 @@ NtAllocateVirtualMemory(IN HANDLE ProcessHandle,
(PMMADDRESS_NODE*)&Process->VadFreeHint,
&StartingAddress);
ASSERT(NT_SUCCESS(Status));
//
// Now we know where the allocation ends. Make sure it doesn't end up
// somewhere in kernel mode.
//
EndingAddress = ((ULONG_PTR)StartingAddress + PRegionSize - 1) | (PAGE_SIZE - 1);
if ((PVOID)EndingAddress > MM_HIGHEST_VAD_ADDRESS)
{
Status = STATUS_NO_MEMORY;
goto FailPath;
}
}
else if (MiCheckForConflictingNode(StartingAddress >> PAGE_SHIFT,
EndingAddress >> PAGE_SHIFT,
@ -3357,17 +3369,6 @@ NtAllocateVirtualMemory(IN HANDLE ProcessHandle,
goto FailPath;
}
//
// Now we know where the allocation ends. Make sure it doesn't end up
// somewhere in kernel mode.
//
EndingAddress = ((ULONG_PTR)StartingAddress + PRegionSize - 1) | (PAGE_SIZE - 1);
if ((PVOID)EndingAddress > MM_HIGHEST_VAD_ADDRESS)
{
Status = STATUS_NO_MEMORY;
goto FailPath;
}
//
// Write out the VAD fields for this allocation
//