Driver Verifier warning

NTDEV
1

Hi,

In my driver, I am allocating memory in the paged
pool on receiving an IOCTL. I allocate it using
ExAllocatePool() and then use MmProbeandLockPages to
lock it. I need to pass on the user mode address of
this buffer back to the application, hence I call
MmMapLockedPages.
When I test my driver with Driver Verifier, I get a
message saying “MmMapLockedPages used instead of
MmMapLockedPagesSpecifyCache.This can cause the system
to bugcheck whenever the resources are low. Please fix
the driver”. What is wrong here ? My driver works
perfectly. Does this mean this is a bug ?

Thanks for all help.
Madhu

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2

MmMapLockedPages bugchecks if you run out of system PTEs.

MmMapLockedPagesSpecifyCache, I think depending on how you call it,
can simply fail and you can try to deal with the failure.

Dave Cox
Hewlett-Packard Co.
SSO/OVBU/SRM (Santa Barbara)
https://ecardfile.com/id/Dave+Cox

-----Original Message-----
From: M V [mailto:xxxxx@yahoo.com]
Sent: Wednesday, June 20, 2001 8:49 AM
To: NT Developers Interest List
Subject: [ntdev] Driver Verifier warning

Hi,

In my driver, I am allocating memory in the paged
pool on receiving an IOCTL. I allocate it using
ExAllocatePool() and then use MmProbeandLockPages to
lock it. I need to pass on the user mode address of
this buffer back to the application, hence I call
MmMapLockedPages.
When I test my driver with Driver Verifier, I get a
message saying “MmMapLockedPages used instead of
MmMapLockedPagesSpecifyCache.This can cause the system
to bugcheck whenever the resources are low. Please fix
the driver”. What is wrong here ? My driver works
perfectly. Does this mean this is a bug ?

Thanks for all help.
Madhu

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