What could be happening in Safe Mode to make my heap corruption bug go away?

Raymond Chen November 30, 2016 Nov 30, 2016 11/30/16

A customer had a program that encountered heap corruption bugs, and they found that the bugs didn't occur when the system was running Safe Mode. What is so special about Safe Mode that makes the bug go away, and how can we get that Safe Mode-like behavior all the time? While we're at it, let's make the entire plane out of the black box. In ...

If I simply want to create a registry key but don’t intend to do anything else with it, what security access mask should I ask for?

Raymond Chen November 28, 2016 Nov 28, 2016 11/28/16

A customer wanted to create a registry key if it didn't already exist, but they weren't interested in writing anything to the key yet. They just wanted to ensure that it existed. Now, we know that the Reg­Create­Key­Ex function will either open a key (if it exists) or create a key (if it doesn't already exist). That seems to fit ...

Lock free many-producer/single-consumer patterns: A work queue of distinct events, FIFO

Raymond Chen November 25, 2016 Nov 25, 2016 11/25/16

At last, our long national nightmare is over: The end of the miniseries on lock-free many-producer/single-consumer patterns. We'll finish up with the case where there are many producers generating work, and one consumer performing the work, and the work items must be processed in the order they were submitted. We can build on the algorithm we...

Lock free many-producer/single-consumer patterns: A work queue of distinct events, order not important

Raymond Chen November 24, 2016 Nov 24, 2016 11/24/16

Almost done with our miniseries on lock-free many-producer/single-consumer patterns. Today, we'll look at the case of multiple producers generating distinct work items which cannot be coalesced, but for which the order of processing is not important. As I noted last time, you can view this as a scenario built on top of the previous one. In ...

Lock free many-producer/single-consumer patterns: A work queue of identical non-coalescable events

Raymond Chen November 23, 2016 Nov 23, 2016 11/23/16

Onward with our miniseries on lock-free many-producer/single-consumer patterns. Today, we're going to look at the case where you have a work queue where there can be multiple work items, and you need to perform them all, but each item is identical. For example, you may have a Buy It button. Each time the user clicks the button, you want to ...

Lock free many-producer/single-consumer patterns: A work queue where the last one wins

Raymond Chen November 22, 2016 Nov 22, 2016 11/22/16

Continuing our miniseries on lock-free many-producer/single-consumer patterns, we're going to look at the case where you have a work queue where there can be multiple work items, but each work item replaces the previous one. You see this pattern when the work is something like Update. If you update with one set of data, and then update with a...

Lock free many-producer/single-consumer patterns: A work queue with task coalescing

Raymond Chen November 21, 2016 Nov 21, 2016 11/21/16

Today we're going to implement a very simple producer/consumer pattern: There are many producers who are producing work, and a single consumer who processes the work. The work is all identical, and it is idempotent. That means that doing the work twice is the same as doing it once. You see this pattern when the work is something like Refresh...