CONTAINING_RECORD with null pointer

NTDEV
1

Hi,

I was just looking at a driver crash on 32-bit W2K8 and see some code
applied CONTAINING_RECORD to a null pointer.

Does anybody know if different WIndows versions trap invalid addresses in
the range of 0xfffffxxx differently? W2K8 seemed to know it was a null
pointer reference, and we have never seen this error on W2K3, but suspect it
may still happen.

Jan

2

Jan Bottorff wrote:

I was just looking at a driver crash on 32-bit W2K8 and see some code
applied CONTAINING_RECORD to a null pointer.

Does anybody know if different WIndows versions trap invalid addresses
in the range of 0xfffffxxx differently? W2K8 seemed to know it was a
null pointer reference, and we have never seen this error on W2K3, but
suspect it may still happen.

I don’t think 2008 changed anything here. Virtual addresses through
ffdfffff are meaningful, but ffe00000 through ffffffff are unmapped.
You should get a page fault, or an “IRQL not less or equal” blue screen.

–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.

3

In a vain attempt to make pointer casting respect NULL I usually code such
things as:

pFoo = (pFooField ? CONTAINING_RECORD(pFooField, FOO, Field) : NULL);

if a NULL value is permitted to be propagated. At least that prevents the
deref on some very high address and is more likely to be observed as a NULL
Ptr Deref in a bugcheck.

More often than not I try to wrap such stuff in a FORCEINLINE ?cast?
function that will ASSERT() on the NULL pointer in a checked build.

Of course, if this is not your code, then there is not much you can do about
it L.

Good Luck

Dave Cattley

Consulting Engineer

Systems Software Development

From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jan Bottorff
Sent: Wednesday, October 08, 2008 5:17 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] CONTAINING_RECORD with null pointer

Hi,

I was just looking at a driver crash on 32-bit W2K8 and see some code
applied CONTAINING_RECORD to a null pointer.

Does anybody know if different WIndows versions trap invalid addresses in
the range of 0xfffffxxx differently? W2K8 seemed to know it was a null
pointer reference, and we have never seen this error on W2K3, but suspect it
may still happen.

Jan

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