Comments (5)
What the slide is saying that without protection, the access may be unsafe.
Now even if you did protection, the pointer may have been freed between the time you obtained it and called protect(cur). We perform validation to ensure that this does not happen.
from cs431.
Hence we can call protect on an already freed pointer safely? I.e. the protect method doesn't dereference the pointer
Is this: protect(null)
also safe then?
from cs431.
protect(null)
itself is safe (hence in the homework Shield::protect()
is a safe function) what isn't safe is dereference of a null pointer or protected pointer without validation. This is precisely why we validate the pointer and also check if its null.
from cs431.
Okay, so protecting a pointer to invalid memory is safe. Then why does it say "unsafe protect()" on slide 7?
from cs431.
Ah, so the situation in slide 7 is a case where the dereference is unsafe even if validation succeeds. That's why its saying "unsafe protect()".
from cs431.
Related Issues (20)
- [Question] I get VALID?=timeout with full score log HOT 4
- [Lecture] Suggestion on teaching promising semantics HOT 1
- Optional Q&A session on June 5th (Wed)
- [Question] Understanding of access hazard & ABA hazard HOT 1
- Server rebooting scheduled (Jun 5, Wed, 10pm~) HOT 1
- [Question] zip is not installed on server HOT 2
- gg.kaist.ac.kr down for preparing for the final exam HOT 1
- [Question] find_harris_herlihy_shavit relaxed load for tag HOT 6
- [Question] Timeout on growable_array stress_concurrent with cargo_asan HOT 2
- [Question] How to get previous node of bucket sentinel? HOT 8
- [Question] Code lines for maintaining the invariants of stack/queue HOT 1
- [Question] About the problem of 2022 Fall HOT 2
- [Question] ordering in stack push for maintaining invariant HOT 1
- Final claim session on June 17th (Mon) HOT 4
- [Question] HW 7 reason for having atomicUsize type in hazard field HOT 2
- [Question] [HW7] Failed Basic Tests in hazard.rs HOT 3
- [Question] HW7 Dropping the Hazard Bag HOT 3
- [Question] Partial Points on HW7 HOT 1
- [Question] err happend when run cargo run hello_server in terminal HOT 1
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from cs431.