title: pool extension command description: The pool extension displays information about a specific pool allocation or about the entire system-wide pool. ms.assetid: 1c224e0c-d50c-487e-8238-9be054368ac2 keywords: ["pool", "pool, See "memory"", "pooltag.txt file", "pool tag", "memory, pool tag", "pool Windows Debugging"] ms.author: windowsdriverdev ms.date: 05/23/2017 ms.topic: article ms.prod: windows-hardware ms.technology: windows-devices topic_type:
- apiref api_name:
- pool api_type:
The !pool extension displays information about a specific pool allocation or about the entire system-wide pool.
!pool [Address [Flags]]
Specifies the pool entry to be displayed. If Address is -1, this command displays information about all heaps in the process.
If Address is 0 or omitted, this command displays information about the process heap.
Specifies the level of detail to be used. This can be any combination of the following bit values; the default is zero:
Bit 0 (0x1)
Causes the display to include the pool contents, not just the pool headers.
Bit 1 (0x2)
Causes the display to suppress pool header information for all pools, except the one that actually contains the specified Address.
Bit 31 (0x80000000)
(Windows XP and later) Suppresses the description of the pool type and pool tag in the display.
Windows XP and later
For information about memory pools, see the Windows Driver Kit (WDK) documentation and Microsoft Windows Internals, by Mark Russinovich and David Solomon. (These resources may not be available in some languages and countries.)
In Windows XP and later versions of Windows, the !pool extension displays the pool tag associated with each allocation. The owner of that pool tag is also displayed. This display is based on the contents of the pooltag.txt file. This file is located in the triage subdirectory of your Debugging Tools for Windows installation. If you want , you can edit this file to add additional pool tags relevant to your project.
Warning If you install an updated version of Debugging Tools for Windows in the same directory as the current version, it overwrites all of the files in that directory, including pooltag.txt. If you modify or replace the sample pooltag.txt file, be sure to save a copy of it to a different directory. After reinstalling the debuggers, you can copy the saved pooltag.txt over the default version.
If the !pool extension reports pool corruption, you should use !poolval to investigate.
Here is an example. If Address specifies 0xE1001050, the headers of all pools in this block are displayed, and 0xE1001050 itself is marked with an asterisk (*).
kd> !pool e1001050 e1001000 size: 40 previous size: 0 (Allocated) MmDT e1001040 size: 10 previous size: 40 (Free) Mm *e1001050 size: 10 previous size: 10 (Allocated) *ObDi e1001060 size: 10 previous size: 10 (Allocated) ObDi e1001070 size: 10 previous size: 10 (Allocated) Symt e1001080 size: 40 previous size: 10 (Allocated) ObDm e10010c0 size: 10 previous size: 40 (Allocated) ObDi .....
In this example, the right-most column shows the pool tag. The column to the left of this shows whether the pool is free or allocated.
The following command shows the pool headers and pool contents:
kd> !pool e1001050 1 e1001000 size: 40 previous size: 0 (Allocated) MmDT e1001008 ffffffff 0057005c 004e0049 004f0044 e1001018 ffffffff 0053005c 00730079 00650074 e1001040 size: 10 previous size: 40 (Free) Mm e1001048 ffffffff e1007ba8 e1501a58 01028101 e1001058 ffffffff 00000000 e1000240 01028101 *e1001050 size: 10 previous size: 10 (Allocated) *ObDi e1001058 ffffffff 00000000 e1000240 01028101 e1001068 ffffffff 00000000 e10009c0 01028101 e1001060 size: 10 previous size: 10 (Allocated) ObDi e1001068 ffffffff 00000000 e10009c0 01028101 e1001078 ffffffff 00000000 00000000 04028101 ......