Goals

Have my app run normally without crashes.

Expected Results

Same as "Goals" (above).

Actual Results

I'm seeing EXC_BAD_ACCESS in at least 2 different places. Please see:-

This might be related to #6556, but since that has been closed for a while, I decided to open a new issue for this.

Steps for others to Reproduce

So far, I have been unable to reproduce this in a sample project, but, here are a few things I can tell:-

• Crash occurs randomly during a mass import when several write transactions are committed in quick succession on a single serial operation queue.
• This happens on brand new installation (i.e. not upgrading from old file format, also, not following compaction).
• My realm is stored in shared app group container (if that matters).
• So far, I have been unable to reproduce this on the Simulator, but it occurs fairly frequently when running on an actual device (iPad 6th generation).
• Since one of the crashes happens in do_encryption_read_barrier, I think it's also worth mentioning that my Realm is not encrypted.
• _{I have noticed that I can get rid of this crash if is slow down my writes (since my writes are committed on a serial background queue using NSOperation subclasses, adding [NSThread sleepForTimeInterval:1.0]; after [realm commitWriteTransaction]; in my NSOperation subclass is enough, but this is obviously not ideal).} I eventually hit this crash irrespective on this change.
• One way that I have found to get rid of these crashes is to not use realm notifications of any kind, or use KVO on realm objects. (Which is also not ideal).
• A pattern I have noticed: This crash manifests itself after I have crashed once with a "mmap() failed: Cannot allocate memory size: XXXXXXXX offset: 0" exception during a mass import upon a fresh install, after which there are only EXC_BAD_ACCESS crashes no "mmap() failed" exceptions. I must say though: the exact same code had absolutely no "mmap() failed" exceptions or EXC_BAD_ACCESS crashes when used with realm-cocoa version 4.3.2.

Code Sample

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None right now.

Version of Realm and Tooling

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Realm framework version: 5.3.5

Realm Object Server version: N/A

Xcode version: 12 Beta 6

iOS/OSX version: iOS 14 Beta 6

Dependency manager + version: SPM (or Dynamic Framework built from source)