Loading jnidispatch on Android 15 with 16 KB page size leads to crash

[lisa-bella97]

1. Version of JNA and related jars
   5.16.0@aar
2. Version and vendor of the java virtual machine
   ART, Android 15
   System.getProperty("java.vm.version") = "2.1.0"
3. Operating system
   Android 15 with 16 KB page size
4. System architecture (CPU type, bitness of the JVM)
   arm64-v8a
5. Complete description of the problem
   Loading jnidispatch using System.loadLibrary("jnidispatch") is OK on Android 15 or less with 4 KB page size, but is not OK (leads to SIGSEGV crash) on Android 15 with 16 KB page size (support of this page size in Android 15 is described in docs).
   System.loadLibrary("jnidispatch") is called on Android platform in loadNativeDispatchLibrary function that is called in static block of JNA class Native, so you cannot properly use, for example, Native.load function on Android 15 with 16 KB page size.

To test this behaviour, we used the corresponding Android Studio emulator and Google Pixel 8 and Google Pixel 9 physical devices with 16 KB mode enabled.

Info about emulator:
Emulator version: 35.1.13-11943732 (HVF 14.5.0)
Host machine: macOS 14.5
Api level: 35
Type: Google APIs PlayStore Page Size 16 KB

Info about Google Pixel 8:
Api level: 35
Build number: AP41.240925.009

Info about Google Pixel 9:
Api level: 35
Build number: BP11.241121.010

6. Steps to reproduce
   You can find minimal sample here. Launching this app on Android 15, 16-KB-based emulator or some Google Pixel physical devices with 16 KB mode enabled will lead to SIGSEGV crash, full log with dump.

Related issue: #1618

[matthiasblaesing]

This should have fixed the issue: 17f4e59

It is unclear why it does not and it is unclear why that was not found when testing. This needs someone with interest in Android and willing to see where this goes wrong.

[matthiasblaesing]

I can't reproduce the problem. I modified the onCreate method in the sample app (btw: thanks, very useful) to this:

        Log.d("MY_LOGS", "Loading library jnidispatch")
        System.loadLibrary("jnidispatch") // This causes crash on Android 15 emulator with 16 KB page size
        var p = Runtime.getRuntime().exec(arrayOf("getconf", "PAGE_SIZE"));
        p.waitFor();
        var pageSize = p.inputStream.readAllBytes().toString(Charsets.UTF_8);
        Log.d("MY_LOGS", "jnidispatch is loaded. Version: " + Native.VERSION + " / Version Native: " + Native.VERSION_NATIVE + " / Page size: " + pageSize);

And get the expected result

Loading library jnidispatch
Load /data/app/~~QPQEWTIZJtTKYiMg6KMS_w==/com.example.testapp-8ycvvd3YvKiQlClPrJpUJw==/base.apk!/lib/x86_64/libjnidispatch.so using ns clns-7 from class loader (caller=/data/data/com.example.testapp/code_cache/.overlay/base.apk/classes4.dex): ok
jnidispatch is loaded. Version: 5.16.0 / Version Native: 7.0.3 / Page size: 16384

This looks sane to me. I can not check on arm64 though as the emulator can't be started:

matthias@enterprise:~$ bin/android-sdk-linux_86/emulator/emulator @Pixel_9_API_35_arm64_-_16k_pages
INFO    | Android emulator version 35.2.10.0 (build_id 12414864) (CL:N/A)
INFO    | Graphics backend: gfxstream
INFO    | Found systemPath /home/matthias/bin/android-sdk-linux_86/system-images/android-35/google_apis_ps16k/arm64-v8a/
PANIC: Avd's CPU Architecture 'arm64' is not supported by the QEMU2 emulator on x86_64 host.
matthias@enterprise:~$

[lisa-bella97]

What device (or emulator) do you use for testing? With x64 architecture?

I check your code on my Google Pixel 9 ARM64 physical device with 4 KB page size and 16 KB page size, Runtime.getRuntime().exec(arrayOf("getconf", "PAGE_SIZE")) returned 4096 for 4 KB page size and 16384 for 16 KB page size (as expected), but SIGSEGV crash occured in case of 16 KB page size.

I recorded videos to show this behaviour: https://drive.google.com/drive/folders/12vZfRMl4FKeDgM4lqOTGZLhHY_KK54G-?usp=sharing

[matthiasblaesing]

@lisa-bella97 I used the emulator for x86-64. Google did not only decided to break ABI they also ensured, that it is ugly to debug. The emulator is not able to emulate arm64 on x86-64 (at least it claims so and starting does not work). My Pixel 7a is not among the few blessed devises that can be switched to 16k mode, so that ends my journey.