trace/traceAsync extensions use try-finally incorrectly [247066503]

Fixed

Bug

Status Update

No update yet.

Description

be...@mercurydevelopment.com

created issue #1

Sep 16, 2022 11:25AM

https://github.com/androidx/androidx/blob/androidx-main/tracing/tracing-ktx/src/main/java/androidx/tracing/Trace.kt#L28

The common pattern for try-finally with resources is to

open()
try {
  doSmth()
} finally {
  close()
}

With Trace.beginSection inside the try block it's possible to break all the sections in the trace by closing unopened section in case if Trace.beginSection throws an exception.

And Trace.beginSection may throw an exception if sectionName exceeds 127 characters (probably there are other cases), so this piece of code will produce wrong trace output:

fun wrongTraceFun() = trace(0..100.joinToString("")) { // just any long name
    Thread.sleep(1)
}

fun anotherFun() = trace("anotherFun") {
   runCatching { wrongTraceFun() }
   Trace.sleep(1000)
}

In the resulting trace file all the sections will be skewed (e.g. anotherFun section will be short, instead of 1s)

Comments

ra...@google.com <ra...@google.com> #2Sep 19, 2022 10:45PM

A couple of questions:

1. Have you saw crash in real device or only in simulators?
2. Do you use dynamic feature for language ID?

ra...@google.com <ra...@google.com> #3Sep 19, 2022 10:46PM

Tested on Android 12 Emulator with custom executor, but cannot repro this issue.

be...@mercurydevelopment.com <be...@mercurydevelopment.com> #4Sep 19, 2022 11:04PM

Second crash in the description is from a real device. Experienced it myself on two different Xiaomi phones, plus lots of crashes from users in the Google Play console.
Dynamic features are not used in the application.

As a wild guess, I have downgraded build tools from 31.0.0 to 30.0.3, compileSdk from 31 to 30, and moved all work with Language ID to the service in a separate process (just to be sure that crash can kill secondary process instead of main). This combination is in beta for 2 days by now and I don't see any SIGSEGV crashes.

ra...@google.com <ra...@google.com> #5Sep 19, 2022 11:06PM

Hmm, I feel the crash might be something related to separate/secondary process.

I also changed compileSdk and targetSDK to 31 but still cannot repro this issue.

be...@mercurydevelopment.com <be...@mercurydevelopment.com> #6Sep 19, 2022 11:16PM

On the contrary, there was no separate process before, when crashes started.

In the new build (with the aforementioned changes) I can see SIGSEGV crash, but only one instead of dozens and it has a bit different backtrace:

signal 11 (SIGSEGV), code 1 (SEGV_MAPERR)
liblanguage_id_jni.so (offset 0x11e000)

backtrace:
  #00  pc 000000000003c7c0  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/split_config.arm64_v8a.apk!lib/arm64-v8a/liblanguage_id_jni.so (offset 0x11e000)
  #00  pc 000000000003b960  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/split_config.arm64_v8a.apk!lib/arm64-v8a/liblanguage_id_jni.so (offset 0x11e000)
  #00  pc 000000000003bb48  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/split_config.arm64_v8a.apk!lib/arm64-v8a/liblanguage_id_jni.so (offset 0x11e000)
  #00  pc 000000000003bafc  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/split_config.arm64_v8a.apk!lib/arm64-v8a/liblanguage_id_jni.so (offset 0x11e000)
  #00  pc 0000000000036c98  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/split_config.arm64_v8a.apk!lib/arm64-v8a/liblanguage_id_jni.so (offset 0x11e000)
  #00  pc 0000000000032714  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/split_config.arm64_v8a.apk!lib/arm64-v8a/liblanguage_id_jni.so (offset 0x11e000)
  #00  pc 0000000000031cac  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/split_config.arm64_v8a.apk!lib/arm64-v8a/liblanguage_id_jni.so (offset 0x11e000)
  #00  pc 0000000000057438  /data/app/azagroup.reedy-mF7zTu2bv_ELlbFArwNgqA==/oat/arm64/base.odex (offset 0x57000)

cc...@google.com <cc...@google.com> Sep 22, 2022 06:10PM

Reassigned to cc...@google.com.

ap...@google.com <ap...@google.com> #7Sep 27, 2022 11:27PM

Marked as fixed.

FYI, ML Kit launched a new language ID SDK in the latest release, which uses a new language ID model. https://developers.google.com/ml-kit/release-notes#august_11_2021

Could you try the new SDK version(17.0.0) to check if you can still repro this native crash? Thanks!

na...@google.com <na...@google.com> #8Oct 5, 2022 05:14PM

Thank you, I'll try it and check.