We are formulating a optimization problem in Cvxpy and using Mosek solver.
Our problem happens to be infeasible.
Debugging of which, we require these two information from Mosek:
Infeasibility Report: We are able to generate this perfectly.
Certificate of Infeasibility: We are unable to get this.
Is there a way to also get the certificate of infeasibility, when using Mosek with Cvxpy?
Related
I'm struggling to debug a crash that's being reported repeatedly in Crashlytics. Here is a screenshot of the report. Seems that it's caused by Google Analytics (reporting the crash on the GAIThread) but not sure what steps I need to take to address this? I've been unable to reproduce the issue and not even sure what is triggering this.
Has anyone else had experience with EXC_BAD_ACCESS KERN_PROTECTION_FAILURE caused by GA or similar?
Former Crashlytics SDK maintainer here. Information might be stale - best to check in with them for latest information.
The crashtlyics SDK protects itself from infinite recursion (which can produce hundreds of thousands of frames) by truncating repeated frames after a certain threshold. To me, it looks like that's exactly what happened here. The crash occurred in a random function that just happened to be running when the stack overflowed.
What I would do is, first, make sure you have the latest version of this Google SDK. I then might check in with them to see if they know of any reason why that function might recurse. Or, perhaps some documentation covers those conditions and/or options that might affect it's behavior.
I'm using the Z3 SMT solver implemented through python. I have the source code, and I would like to have some, any, indication that the process is running. Is it possible to use some verbose command or anything to get an idea of what the process is currently doing? I know the algorithm behind it, but I want to visualize, even with printf, what is occurring in the code.
Thanks!
You can use:
set_option(verbose=10)
to obtain verbose output to standard err.
After a solver has finished, you can get statistics using the
statistics()
method.
In debug mode you can use
enable_trace("arith")
to get low level traces (here given with "arith" as an example tag).
This is intended for debugging only.
So far as I know, in iOS there are three techniques of function hooking:
preload library using DYLD_INSERT_LIBRARIES
imported symbol table redirection using fishhook
patch the functions when they are already loaded - i.e. already in memory using substrate MSHookFunction
These expose security issues so I wanna be able to detect when such things happen. For point number 1, I can apply function pointer verification to detect. However for 2 and 3, I haven't had any idea. I am very thankful for ideas that can be done to address the issue.
I had the same issue - trying to avoid any potential function hooking within my app.
My app was recently PEN tested and was found to have a vulnerability around function hooking. The security report referenced Frida as one of the main culprits for executing such an act. I'm sure most of you peeps would be familiar with this tool.
OWASP suggests a few remedial solutions for securing your app, but in this context, the section titled Anti-Debugging Checks would be the main focus.
As suggested by OWASP, I used ptrace with PT_DENY_ATTACH - denying a GDB/LLDB process to attach to the application.
From OWASP:
In other words, using ptrace with PT_DENY_ATTACH ensures that no other debugger can attach to the calling process; if a debugger attempts to attach, the process will terminate
Here is the solution I used (for Swift). I also had help from this Raywenderlich.com article (Objective-C). I can confirm that using the linked solution works - the app launches but the debugger cuts out, stopping all logs to the console. This could potentially deter hackers, but there will always be a way to get around this. As stated the Raywenderlich article linked:
Don’t get too comfortable. Hackers often use Cycript, a JavaScript-styled program that can manipulate Objective-C apps at runtime. The scariest thing is that the previous logic to check for debugging activity fails when Cycript is attached. Remember, nothing is truly secure…
However, according to Joseph Lord, writing apps using Swift can hopefully help you here. But then again, the reverse engineer always wins.
I hope this helps, in some way or form ...
We're writing an application which uses our http api, and occasionally it will encounter errors, failed connections, timeouts, etc.
We'd like to, at least in beta, be able to capture these incidents, and forward them to ourselves somehow. Since obviously many of these issues could be due to the actual connection being down, this would need to queue these incidents and send them when a connection is available.
I tried googling for an answer for this but to no avail, came across a bunch of solutions which catch exceptions, but not just random "incidents" (could really just be a string we log somewhere, we'd just include all the details in it).
Short of writing my own coredata (or something) backed queue, I'm at a loss at what a solution for this could be.
Does anyone know of any libs/services which could help with this?
You might want to look into Testflight, or less general purpose, Parse. Not quite sure, but maybe HockeyKit offers a solution for this, too.
You can take a look at Bugfender, it's a product we have built to solve this problem. We have found that while developing an app there are a lot of issues that are not crashes, so we decided to make our own product to help us on this.
It's easy to integrate and you can get the devices logs. Our service works offline and online, we have spent a lot of time to make it reliable and easy to use.
Compared to other products, you don't need any crash to get the logs, you choose when you want them.
I read some of the similar posts on this site that deal with what seems to be the same issue and the responses didn't really seem to clarify things for me.
My application works fine in the simulator. I believe I'm on Bold 9000 with OS 4.6. The app is signed.
My app makes an HTTP call via 3G to fetch an XML result. type is application/xhtml+xml.
In the device, it gives no error. it makes no visual sign of error. I tell the try catch to print the results to the screen and I get nothing.
HttpConnection was taken right out of the demos and works fine in sim.
Since it gives no error, I begin to reflect back on things I recall reading back when the project began. deviceside=true? Something like that?
My request is simply HttpConnection connection = (HttpConnection)Connector.open(url);
where url is just a standard url, no get vars.
Based on the amount of time I see the connection arrows in the corner of the screen, I assume the app is launching the initial communication to my server, then either getting a bad result, or it gets results and the persistent store is not functioning as expected.
I have no idea where to begin with this. Posting code would be ridiculous since it would be basically my whole app.
I guess my question is if anyone knows of any major differences with device versus simulator that could cause something like http connection or persistent store to fail?
A build setting? An OS restriction? Any standard procedure I may have just not known about that everyone should do before beginning device testing?
Thanks
Just providing the URL will not work. You will have to append some info after the URL to determine the transport method your HTTP connection will use. For instance http://example.com;deviceside=true will use DirectTCP (you might also have to supply APN information but that's saved on the device for my phone). http://example.com;interface=wifi will use wi-fi. On OS 5 there's a ConnectionFactory class that makes this a lot easier. Here's a link that goes into more detail.
This was a tough one for me!
As Jonathan said you have to put some parameters in the url to make it work on the device. You shouldn't do it by hand but use the ConnectionFactory instead.
As you may thing this would just make it work but it doesn't!
The real problem is that not the url has been altered because it has ;interface=wifi;deviceside=true in it (in my case). Depending on the webserver accepting your request this could broke the code.
A solution I tried and that works is try to happend a fake parameter like
&foo=true -> &foo=true;deviceside=true
This will result as a standard parameter for the webserver but your device would use it to driver your connection.
On the simulator this work without this extra code because behind it there is a BIS server for you. On the device (as in my case) there isn't because I'm using a development device unregistered and without SIM (just wifi).
Another point is that the HttpConnection class doesn't handle HTTP 302 Redirect and if you get one you have to handle it manually.
It's probably an issue with the APN not being specified. See my answer for this question for details:
video streaming over http in blackberry
I would make this a comment, but I think I don't have enough rep yet for that... So I'll just answer and hope this doesn't get hosed for just pasting in some links.
I've been working on this exact sort of networking issue on our app this past week, and it is indeed tricky as some others have pointed out. Here are two links which really helped us out using HTTP on different devices, especially older devices which do not provide ConnectionFactory.
http://supportforums.blackberry.com/t5/Java-Development/Connecting-your-BlackBerry-http-and-socket-connections-to-the/td-p/206242
The first one has some code examples, including demonstration of querying the system's ServiceBook and CoverageInfo classes to make a decision about what kind of connection will work.