[foreign-memaccess+abi] Integrated: 8268673: Stack walk across optimized entry frame on fresh native thread fails

[Jorn Vernee]

Hi Sebastian,

This sounds very odd, as the code you link to doesn't seem to use 
upcalls? The ProgrammableUpcallHandler.USE_INTRINSICS flag is only used 
to control the invocation mode of upcalls.

May I ask how exactly you're diagnosing this problem?

Jorn

On 15/06/2021 15:48, Sebastian Stenzel wrote:
> Hi,
>
> I have pulled this fix (foreign-jextract commit e4f89d7b0f8) and can 
> confirm that the crashes are gone. However, copying bytes from heap to 
> native buffers still is a little odd. Take this code: [1]; [2]
>
> If I run the project with 
> `-Djdk.internal.foreign.ProgrammableUpcallHandler.USE_INTRINSICS=false`, 
> it copies the contents of HELLO_STR to the segment. Without the flag 
> it copies 13 null-bytes, though. 13 being the correct length of the 
> source buffer.
>
> I guess this is not related to the stack walking problem. The only 
> thing I can tell is that said flag has some influence on the behaviour.
>
> Cheers!
> Sebastian
>
>
> [1] my upcall method: 
> https://github.com/skymatic/fuse-panama/blob/3e5dc43ec7a6ba7e2c39fcce0db48d4350fdc0b3/src/main/java/de/skymatic/fusepanama/FuseOperations.java#L222-L227 
> <https://github.com/skymatic/fuse-panama/blob/3e5dc43ec7a6ba7e2c39fcce0db48d4350fdc0b3/src/main/java/de/skymatic/fusepanama/FuseOperations.java#L222-L227>
> [2] method invoked during upcall, which copies bytes to the specified 
> segment: 
> https://github.com/skymatic/fuse-panama/blob/3e5dc43ec7a6ba7e2c39fcce0db48d4350fdc0b3/src/test/java/de/skymatic/fusepanama/examples/HelloPanamaFileSystem.java#L109-L112 
> <https://github.com/skymatic/fuse-panama/blob/3e5dc43ec7a6ba7e2c39fcce0db48d4350fdc0b3/src/test/java/de/skymatic/fusepanama/examples/HelloPanamaFileSystem.java#L109-L112>
>
>
>> On 14. Jun 2021, at 17:09, Jorn Vernee <jvernee at openjdk.java.net 
>> <mailto:jvernee at openjdk.java.net>> wrote:
>>
>> On Mon, 14 Jun 2021 12:13:52 GMT, Jorn Vernee <jvernee at openjdk.org 
>> <mailto:jvernee at openjdk.org>> wrote:
>>
>>> Hi,
>>>
>>> When native code creates a new thread and calls a Panama upcall, and 
>>> during that upcall a stack walk is triggered, getting the sender 
>>> frame for the entry frame is not possible, and should not be attempted.
>>>
>>> For JNI this case is handled already by indicating the end of the 
>>> stack frame stream, but for Panama upcalls it is not, and the VM 
>>> will either hit an assert or crash when trying to find the last Java 
>>> frame before the entry frame (which does not exist in this case).
>>>
>>> This patch adds handling for panama upcalls frames to 
>>> `frame::is_first_frame`, which is used by the stack walking code to 
>>> determine when to stop walking.
>>>
>>> Thanks,
>>> Jorn
>>
>> This pull request has now been integrated.
>>
>> Changeset: 2287ca5a
>> Author:    Jorn Vernee <jvernee at openjdk.org <mailto:jvernee at openjdk.org>>
>> URL: 
>> https://git.openjdk.java.net/panama-foreign/commit/2287ca5a530c348bc4ec7c0c6774e8ed9101dffa 
>> <https://git.openjdk.java.net/panama-foreign/commit/2287ca5a530c348bc4ec7c0c6774e8ed9101dffa>
>> Stats:     194 lines in 11 files changed: 193 ins; 0 del; 1 mod
>>
>> 8268673: Stack walk across optimized entry frame on fresh native 
>> thread fails
>>
>> Reviewed-by: mcimadamore
>>
>> -------------
>>
>> PR: https://git.openjdk.java.net/panama-foreign/pull/558 
>> <https://git.openjdk.java.net/panama-foreign/pull/558>
>