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macosunixsignalscoredump

Core Dumps aren't written to /cores on Mac OS Monterey

I've been banging my head against this for a while. Obviously read this: Where are core dumps written on Mac?

And this which lead to this.

Just so we're 100% clear:

I did:

touch  /cores/x
rm /cores/x

So write permission is good.

Did

ulimit -c unlimited

So cores should be generated.

But even a trivial:

sleep 100 & killall -SIGSEGV sleep

Doesn't generate a core. My current bet is that one of the filesystem protection features of the OS is giving me grief. Another possibility is that this is related to ARM (Running on an M1 Max).

Any ideas are very welcome... I even tried this unsuccessfully: (Mac) leave core file where the executable is instead of /cores?

Solution

  • I'm currently on Mac OS Monterey. The solution suggested at https://developer.apple.com/forums/thread/694233?answerId=695943022#695943022 worked for me.

    A quick summary: it is now necessary to enable com.apple.security.get-task-allow entitlement per executable.

    Example with cat:

    1. Make a copy first. Required since cat is on a read-only filesystem.

      % cp $(which cat) cat-copy

    2. Create a dummy .entitlements with the com.apple.security.get-task-allow entitlement set:

      % /usr/libexec/PlistBuddy -c "Add :com.apple.security.get-task-allow bool true" tmp.entitlements
File Doesn't Exist, Will Create: tmp.entitlements

    3. Re-sign cat-copy with those entitlements:

      % codesign -s - -f --entitlements tmp.entitlements cat-copy 
CrashSelf: replacing existing signature