Example fails with SIGSEGV on MacOS with Nim 2.2.2 and default orc memory manager

[martin-c]

The first example

import serial

for port in listSerialPorts():
  echo port

compile with
nim c --stacktrace:on example.nim

Compilation works es expected. But running the produced binary results in

Traceback (most recent call last)
/Users/martin/.nimble/pkgs2/serial-1.2.0-85079d0e3a6e3f1478357c016e03308b8ede3a05/serial/private/utils/list_serialports_mac.nim(96) example
/Users/martin/.nimble/pkgs2/serial-1.2.0-85079d0e3a6e3f1478357c016e03308b8ede3a05/serial/private/utils/list_serialports_mac.nim(84) getDeviceName
/usr/local/Cellar/nim/2.2.2/nim/lib/system/arc.nim(188) nimRawDispose
/usr/local/Cellar/nim/2.2.2/nim/lib/system/alloc.nim(1165) dealloc
/usr/local/Cellar/nim/2.2.2/nim/lib/system/alloc.nim(1063) rawDealloc
/usr/local/Cellar/nim/2.2.2/nim/lib/system/alloc.nim(815) addToSharedFreeListBigChunks
SIGSEGV: Illegal storage access. (Attempt to read from nil?)

Compiling with --mm:refc creates binary which works, but no serial ports are listed. (MacOS 15.3)

[euantorano]

Thanks, I’ll need to investigate and see where it’s going wrong.

On Sun, 9 Feb 2025, at 17:25, martin-c wrote: The first example import serial for port in listSerialPorts(): echo port compile with `nim c --stacktrace:on example.nim` Compilation works es expected. But running the produced binary results in `Traceback (most recent call last) /Users/martin/.nimble/pkgs2/serial-1.2.0-85079d0e3a6e3f1478357c016e03308b8ede3a05/serial/private/utils/list_serialports_mac.nim(96) example /Users/martin/.nimble/pkgs2/serial-1.2.0-85079d0e3a6e3f1478357c016e03308b8ede3a05/serial/private/utils/list_serialports_mac.nim(84) getDeviceName /usr/local/Cellar/nim/2.2.2/nim/lib/system/arc.nim(188) nimRawDispose /usr/local/Cellar/nim/2.2.2/nim/lib/system/alloc.nim(1165) dealloc /usr/local/Cellar/nim/2.2.2/nim/lib/system/alloc.nim(1063) rawDealloc /usr/local/Cellar/nim/2.2.2/nim/lib/system/alloc.nim(815) addToSharedFreeListBigChunks SIGSEGV: Illegal storage access. (Attempt to read from nil?)

`

…

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[euantorano]

As an experiment, I've created the same code in Swift, and it compiles and runs fine there. I'm trying to work out what Nim is doing differently, but I suspect it's something related to ORC.

Example Swift implementation:

import Foundation

func listSerialPorts() {
    var it: io_iterator_t = io_iterator_t()
    
    let kernResult = withUnsafeMutablePointer(to: &it) { itPtr in
        IOServiceGetMatchingServices(
            kIOMainPortDefault,
            IOServiceMatching("IOSeriaolBSDClient"),
            itPtr
        )
    }
    
    if kernResult == KERN_SUCCESS {
        defer {
            IOObjectRelease(it)
        }
        
        while IOIteratorIsValid(it) != 0 {
            let service = IOIteratorNext(it)
            
            if service == 0 {
                break
            }
            
            let key = CFStringCreateWithCString(
                kCFAllocatorDefault,
                "IOCalloutDevice",
                kCFStringEncodingASCII
            )
            
            let cfContainer = IORegistryEntryCreateCFProperty(
                service,
                key,
                kCFAllocatorDefault,
                0
            )
            
            if let cfContainer {
                let name = CFStringGetCStringPtr((cfContainer as! CFString), kCFStringEncodingASCII)
                
                print(String(cString: name!))
            }
        }
    }
}

listSerialPorts()