[Bug threads/29681] New: VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[Bug threads/29681] New: VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

            Bug ID: 29681
           Summary: VS 2022 Preview C++ Android debugger crashes on
                    breakpoint in thread on arm64v8a device
           Product: gdb
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: threads
          Assignee: unassigned at sourceware dot org
          Reporter: daniel.hilburn at outlook dot com
  Target Milestone: ---

I have an Android app which I am attempting to debug on my Samsung Galaxy S21.
I’m using VS 2022 Preview. Ultimately, my goal is to create a fully native
project using the NativeActivity, as the old project template using ANT was
removed. This project is just the provided Gradle Android App project modified
to use the NativeActivity implemented in a second SharedLib project. When I
deploy the app to my phone and connect the debugger, it correctly starts the
NativeActivity and I can hit a breakpoint in the ANativeActivity_onCreate
function. So far so good. ANativeActivity_onCreate creates a second thread on
which to run my app code so that ANativeActivity_onCreate can return. That
second thread executes correctly without crashing. However, if I put a
breakpoint into the code running on that second thread, the debugger throws an
error and stops the app and disconnects.

I’ve enabled debugger logging using “Debug.MIDebugLog /On:MIDebugLog.txt
/OutputWindow” in the Command Terminal window in VS and the error it provides
is “Call Frame Instruction op 45 in vendor extension space is not handled on
this architecture.” It seems to be unable to retrieve the call stack from the
second thread. If I put a breakpoint in the ANativeActivity_onCreate
immediately after it creates the thread, I can see the new thread in the
Threads window. However, selecting it shows the same error and Visual Studio
shows a window explaining that the selected thread is not supported.

I contacted Visual Studio support about this issue
(https://developercommunity.visualstudio.com/t/VS-2022-Preview-C-Android-debugger-cra/10165250?space=62&entry=problem)
and they said that it is an issue with GDB and recommended that I contact you
guys.

I have attached an AndroidApp.zip file containing the small example project.
The test project is basically just the provided C++ Android App Gradle project
with an additional C++ Android Shared Object Library project compiling the
android_native_app_glue.c code. You can reproduce by putting a breakpoint in
android_native_app_glue.c in android_app_create() at line 314 and another in
android_app_entry() at line 240. The first breakpoint will hit on the initial
thread without trouble and the second breakpoint from the second thread will
cause the debugger to crash.

Please let me know if you need any additional information from me on this
issue, and thanks in advance for your assistance.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #1 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
Created attachment 14397
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14397&action=edit
Contains a test VS solution to demonstrate the bug, MIDebugLog.txt with gdb
output from a crash, and AboutVS.txt with Visual Studio installation info

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

Daniel Hilburn <daniel.hilburn at outlook dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #14397|Contains a test VS solution |AndroidApp.zip
        description|to demonstrate the bug,     |
                   |MIDebugLog.txt with gdb     |
                   |output from a crash, and    |
                   |AboutVS.txt with Visual     |
                   |Studio installation info    |

--- Comment #2 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
Comment on attachment 14397
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14397
AndroidApp.zip

Contains a test VS solution to demonstrate the bug, MIDebugLog.txt with gdb
output from a crash, and AboutVS.txt with Visual Studio installation info

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #3 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
Comment on attachment 14397
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14397
AndroidApp.zip

Contains a test VS solution to demonstrate the bug, MIDebugLog.txt with gdb
output from a crash, and AboutVS.txt with Visual Studio installation info.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[simark at simark dot ca]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

Simon Marchi <simark at simark dot ca> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |simark at simark dot ca

--- Comment #4 from Simon Marchi <simark at simark dot ca> ---
When you say it crashes, are you talking about this?

17: (2106595) <-1060-stack-list-frames 0 1000
17: (2106628) ->1060^error,msg="Call Frame Instruction op 45 in vendor
extension space is not handled on this architecture."

That's the only abnormal thing I see, and that would prevent VSCode from
showing a stack trace.

According to the message, a DWARF CFI expression uses the 45 (0x2d)
vendor-specific operator.  From your logs, I see that you are on AArch64
(ARM64), so it's probably
DW_CFA_AARCH64_negate_ra_state:

https://gitlab.com/gnutools/binutils-gdb/-/blob/091782c46d9b321f5b7c5e5330b5febe015d73d6/include/dwarf2.def#L791

I see that we handle it here:
https://gitlab.com/gnutools/binutils-gdb/-/blob/091782c46d9b321f5b7c5e5330b5febe015d73d6/gdb/aarch64-tdep.c#L1339

Looks like you are using GDB 8.3, which is too old.  It looks like it was added
in GDB 9.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #5 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
Yes. I suspect that it isn't really crashing, but just that the callstack error
causes the VS debugger to stop, which immediately closes the app.

Thank you so much for the detailed and useful information. I'll try updating my
GDB version and see if that fixes things.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #6 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
In attempting to update my gdb version, it appears that Visual Studio's Android
debugger is adb and it uses gdbserver deployed to the device with the deployed
app to debug it remotely. Where did you see my gdb version information? I'd
like to also check the gdbserver and adb versions to make sure that they are
also up-to-date.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[simark at simark dot ca]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #7 from Simon Marchi <simark at simark dot ca> ---
(In reply to Daniel Hilburn from comment #6)
> In attempting to update my gdb version, it appears that Visual Studio's
> Android debugger is adb and it uses gdbserver deployed to the device with
> the deployed app to debug it remotely. Where did you see my gdb version
> information? I'd like to also check the gdbserver and adb versions to make
> sure that they are also up-to-date.

In your MI logs:

17: (2094895) ->~"GNU gdb (GDB) 8.3\n"

adb is the tool used to access / connect to devices, but you definitely have a
GDB somewhere.  Any idea where it comes from, Android SDK or shipped with a
Visual Studio extension?

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #8 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
As I understand it Visual Studio has a gdb "frontend" (not sure what that
means), so maybe that is it on my PC side of things. The Android NDK ships with
a prebuilt gdbserver, which Visual Studio deploys with my application to the
Android device. I thought that adb was communicating with that, but maybe it is
Visual Studio itself. In trying to track down my local gdb file to update it, I
debugged my application from Visual Studio and looked in Task Manager to see
what programs were running. I saw adb but no gdb, so that's why I was thinking
that VS was using adb. I'll look into how Visual Studio's gdb debugger works
and see if I can track that down.

Incidentally, do you think that the error is originating from the gdbserver on
the device or from the gdb on my host PC? The way it emits seems like Visual
Studio is sending a command to gdbserver to retrieve the callstack when the
breakpoint hits and gdbserver is replying that the specified command is not
handled. Does that correct? If so, that would imply that the host debugger in
VS is more up-to-date than the gdbserver instance running on the device.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[simark at simark dot ca]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #9 from Simon Marchi <simark at simark dot ca> ---
(In reply to Daniel Hilburn from comment #8)
> As I understand it Visual Studio has a gdb "frontend" (not sure what that
> means), so maybe that is it on my PC side of things. The Android NDK ships
> with a prebuilt gdbserver, which Visual Studio deploys with my application
> to the Android device. I thought that adb was communicating with that, but
> maybe it is Visual Studio itself. In trying to track down my local gdb file
> to update it, I debugged my application from Visual Studio and looked in
> Task Manager to see what programs were running. I saw adb but no gdb, so
> that's why I was thinking that VS was using adb. I'll look into how Visual
> Studio's gdb debugger works and see if I can track that down.

You definitely have a gdb binary somewhere, because this kind of chatter in the
logs:

-1060-stack-list-frames 0 1000
1060^error,msg="Call Frame Instruction op 45 in vendor extension space is not
handled on this architecture."

is GDB MI (machine interface).  It is your GUI application (Visual Studio)
talking to GDB.

If I had to guess, adb is involved as the communication bridge between gdb and
gdbserver.

To locate which gdb is used, you could try to look at the processes (ps) while
your debug session is running.  I tried download the Android NDK, but couldn't
find a GDB executable in there.  Perhaps it is downloaded separately /
on-demand.

> Incidentally, do you think that the error is originating from the gdbserver
> on the device or from the gdb on my host PC? The way it emits seems like
> Visual Studio is sending a command to gdbserver to retrieve the callstack
> when the breakpoint hits and gdbserver is replying that the specified
> command is not handled. Does that correct? If so, that would imply that the
> host debugger in VS is more up-to-date than the gdbserver instance running
> on the device.

The error originates from GDB on your host PC.  The stack trace is generated by
GDB on the host, using the DWARF information present in the executable. 
GDBserver doesn't do stack unwind.

Visual Studio talk on your host talks with GDB on your host.  GDB talks to
GDBserver whenever it needs to interact with the debugged process, for instance
to read memory or registers, or to resume threads.  In your case, it's GDB that
generates the error, the DWARF information in the executable contains an
operation that GDB does not know about.

Again, if I had to guess, I'd say that your GDB and GDBserver versions are the
same, if they come from the same place.  In theory, you can upgrade only your
GDB, as it's supposed to be able to talk with older GDBservers.  Some newer
features might not be available, but in most cases it degrades gracefully.  But
in your case, the problem you encounter only concerns work done on the host, so
it should work fine to use a newer GDB with your current GDBserver.  I say
should, because it's not the best tested scenario.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #10 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
Ah! You were absolutely right! I looked again and found it nested underneath
Visual Studio's process in Task Manager. It looks like gdb and gdbserver both
come from the Android NDK. I've posted on the NDK github page to request an
update in the next version.

Thank you so much for all of your help on this. Do you know if there is a
prebuilt gdb binary for windows which I can download? I tried downloading the
12.1 gdb source code, but it won't build for me. I extracted it and then ran
"./configure" and then "make" and it emits "no targets specified and no
makefile found".

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[simark at simark dot ca]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #11 from Simon Marchi <simark at simark dot ca> ---
(In reply to Daniel Hilburn from comment #10)
> Thank you so much for all of your help on this. Do you know if there is a
> prebuilt gdb binary for windows which I can download? I tried downloading
> the 12.1 gdb source code, but it won't build for me. I extracted it and then
> ran "./configure" and then "make" and it emits "no targets specified and no
> makefile found".

I don't know if someone provides a pre-built binary.  What's more is that in
your case, since you want to debug AArch64 code, you'll need to enable the
AArch64 target.  That means passing a flag like
--target=aarch64-something-something to configure.  You can try to start your
existing GDB and do "show configuration" to see how that one was configured,
and start from there.

After that, the build environment on Windows is very different from Linux, so I
may not be able to help you much.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #12 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
You've already helped so much. Thank you! I'll ask NDK support for information
on building gdb. Surely, they know how to do it. =D

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

Daniel Hilburn <daniel.hilburn at outlook dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |NOTABUG

--- Comment #13 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
Marking Resolve NotABug, as this wasn't a bug with gdb or gdbserver. Thanks
again for all of your help.

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[Bug threads/29681] VS 2022 Preview C++ Android debugger crashes on breakpoint in thread on arm64v8a device

[daniel.hilburn at outlook dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29681

--- Comment #14 from Daniel Hilburn <daniel.hilburn at outlook dot com> ---
As a sort of epilogue to this issue, it turns out that Android NDK has dropped
gdb support in favor of lldb. They have a Visual Studio extension called
Android Game Developer Extension which uses that. It seems much better than the
older Visual Studio integration.

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