ExAllocatePoolPriorityUninitialized function (wdm.h)

Article
02/22/2024

This routine is a wrapper and replacement option for ExAllocatePoolWithTagPriority.

ExAllocatePoolPriorityUninitialized allocates pool memory of the specified type.

Syntax

PVOID ExAllocatePoolPriorityUninitialized(
  __drv_strictTypeMatch(__drv_typeExpr)POOL_TYPE PoolType,
  SIZE_T                                         NumberOfBytes,
  ULONG                                          Tag,
  EX_POOL_PRIORITY                               Priority
);

Parameters

PoolType

The type of pool memory to allocate. For a description of the available pool memory types, see POOL_TYPE.

You can modify the enumeration value by performing a bitwise-OR with the POOL_RAISE_IF_ALLOCATION_FAILURE flag defined in wdm.h. This flag causes an exception to be raised if the request cannot be satisfied. Use of this flag is not recommended because it is costly.

Similarly, you can modify the PoolType value by bitwise-ORing this value with the POOL_COLD_ALLOCATION flag (also defined in wdm.h) as a hint to the kernel to allocate the memory from pages that are likely to be paged out quickly. To reduce the amount of resident pool memory as much as possible, you should not reference these allocations frequently. The POOL_COLD_ALLOCATION flag is only advisory.

NumberOfBytes

The number of bytes to allocate.

Tag

The pool tag to use for the allocated memory. For more information, see the Tag parameter of ExAllocatePoolWithTag.

Priority

An EX_POOL_PRIORITY enumeration value specifying the priority of this request.

Return value

ExAllocatePoolPriorityUninitialized returns NULL if there is insufficient memory in the free pool to satisfy the request unless POOL_RAISE_IF_ALLOCATION_FAILURE is specified. Otherwise, the routine returns a pointer to the allocated memory.

Remarks

Memory that ExAllocatePoolPriorityUninitialized allocates is uninitialized. A kernel-mode driver must first zero this memory if it is going to make it visible to user-mode software (to avoid leaking potentially privileged contents)

See the Remarks section of ExAllocatePoolWithTagPriority for additional guidance.

Requirements

Requirement	Value
Minimum supported client	Requires WDK for Windows 10, version 2004. Targets Windows 7 and later versions of the Windows operating system.
Target Platform	Universal
Header	wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
Library	NtosKrnl.lib
DLL	NtosKrnl.exe
IRQL	<= DISPATCH_LEVEL (see Remarks section)
DDI compliance rules	HwStorPortProhibitedDDIs, IrqlExAllocatePool, IrqlExFree2, SpNoWait, StorPortStartIo