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The scheduler I have been working on for my OS class has been getting a "*** stack smashing detected ***" error on the VM I'm using (I'm using Vagrant with virtualbox). This error occurs roughly 50% of the time I run the program. When switching to the VM cluster provided by our professor (connected using SSH on the aforementioned VM), the error never showed up.

My first instinct was that my local VM didn't have enough memory allocated to it and that somehow the code I was running was going out of bounds of where my VM could access. (the test involved performing 128 matrix multiplications of varying sizes each in its own thread)

Can anyone confirm if this is a feasible explanation? My fear is the error is just being ignored on the other VM (I use the same makefile for both that compiles with flags -g and -lm). Thanks!

gormatron3000
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Stack smashing detected is caused when your program overwrites "canary" memory that is above the area where its local variables are located. It's usually due to writing more elements of a local array than were allocated for it. A bug-free program should never do this on any machine, no matter how much or how little memory is available. So your program is buggy and needs to be fixed.

In particular, this error is not caused by simply running out of stack space.

Most likely the other VM has its compiler configured to disable this check by default. You may be able to re-enable it with -fstack-protector. But either way, you should investigate and fix this bug on whichever machine lets you reproduce it.

Nate Eldredge
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