FO->DeviceObject and FO->Vpb is NULL

NTFSD
1

Hi, all

I have a problem with some bugcheck in IRP_MJ_CREATE
handler. When analyzed the crash dump, I found that it is called
in kernel worker thread through our filter driver to LanmanRedirector.

When I examined the file object, I found that some fields seem
strange to me:

FO->Type: 5 (OK)
FO->Size: 0x70 (OK)
FO->DeviceObject: NULL (???)
FO->Vpb: NULL (???)
…
FO->FileName: “\All Users\Start Menu\Programs\SomeShellShortcut.lnk”
…
Has anyone ever seen this situation when DeviceObject and VPB is set to
NULL in the file object (and in create request) ?

Is this situation normal ?

L.

2

Hi, all

I have a problem with some bugcheck in IRP_MJ_CREATE
handler. When analyzed the crash dump, I found that it is called
in kernel worker thread through our filter driver to LanmanRedirector.

When I examined the file object, I found that some fields seem
strange to me:

FO->Type: 5 (OK)
FO->Size: 0x70 (OK)
FO->DeviceObject: NULL (???)
FO->Vpb: NULL (???)
…
FO->FileName: “\All Users\Start Menu\Programs\SomeShellShortcut.lnk”
…
Has anyone ever seen this situation when DeviceObject and VPB is set to
NULL in the file object (and in create request) ?

Is this situation normal ?

L.

3

FileObject->Vpb for redirectors will always be NULL. The Vpb is only
needed for local file system stacks as it is used for the translation
from file system stack to storage stack.

The FileObject->DeviceObject should not be NULL. It should point to the
redirector’s DeviceObject.

If you’ve only seen this once, my best guess is that the file object was
corrupted in some way.

Thanks,
Molly Brown
Microsoft Corporation

This posting is provided “AS IS” with no warranties and confers no
rights.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ladislav Zezula
Sent: Monday, February 02, 2004 10:13 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] FO->DeviceObject and FO->Vpb is NULL

Hi, all

I have a problem with some bugcheck in IRP_MJ_CREATE handler. When
analyzed the crash dump, I found that it is called in kernel worker
thread through our filter driver to LanmanRedirector.

When I examined the file object, I found that some fields seem strange
to me:

FO->Type: 5 (OK)
FO->Size: 0x70 (OK)
FO->DeviceObject: NULL (???)
FO->Vpb: NULL (???)
…
FO->FileName: “\All Users\Start Menu\Programs\SomeShellShortcut.lnk”
…
Has anyone ever seen this situation when DeviceObject and VPB is set to
NULL in the file object (and in create request) ?

Is this situation normal ?

L.

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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