1478415 - MozStackWalk stacks are truncated for rust code

Status: NEW

(Core :: XPCOM, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

Attachment: dmd.out.txt

In trying to investigate bug 1477716, I made a DMD build on linux and ran it in "live" mode:

MOZ_WEBRENDER=1 MOZ_ACCELERATED=1 ./mach run --dmd --mode live

I loaded the page in question and scrolled until it was really laggy, and then did the kill -34 <pid> to get DMD dumps. Then I ran dmd.py on the root process json.gz file to get the heap information. The result is attached - the first block seems to be what I'm looking for, but the stack is unfortunately not particularly useful because it seems like it didn't unwind the usual 8 frames.

Comment 1

[Andrew McCreight [:mccr8]]

DMD just uses the XPCOM stackwalking code so I'd imagine this is more of an issue with that code. I don't know what the expectation for it working with Rust code is.

Comment 2

[Andrew McCreight [:mccr8]]

I guess on Windows and OSX it doesn't use the standard stackwalking, but we are still using MozStackWalk on Linux.