1507550 - Scrub out junk from Rust signatures in LSan white list

Status: RESOLVED FIXED

(Testing :: General, enhancement, P3)

Description

[Andrew McCreight [:mccr8]]

If my patch in bug 1480799 works, the WPT LSan whitelists should have their Rust signatures all scrubbed of the weird junk that seems to change depending on the build or compiler, and the importing mechanism should be changed to also scrub it, so we don't add more. I don't know if those need to be separate bugs or not.

A better fix would be to adjust the lsan-symbolizer to properly demangle Rust symbols, though that would also require regenerating these frames, in a different way. I'm not sure if that is easy or not.

Here's an excerpt of lsan-allowed looks like [1] with some formatting:
alloc_system::platform::_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$::alloc::h5a1f0db41e296502,
alloc_system::platform::_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$::alloc::h82bf91dcf8d89ced,
alloc_system::platform::_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$::alloc::hd3c140e687e2a935,
alloc_system::platform::_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$::realloc::h3ab64a4bcafe2c39,
alloc_system::platform::_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$::realloc::h5c6d61654badfe59,
alloc_system::platform::_$LT$impl$u20$core..alloc..GlobalAlloc$u20$for$u20$alloc_system..System$GT$::realloc::hfdaa883bde7dcfa7,

The idea is the various "h5a1f0db41e296502" stuff should be removed, and not introduced. Looking at the change log for this file, it seems like whatever changes in the compiler periodically, which introduces new leaks at import time, and then the new variant is added, which keeps us from leaking until whatever other compiler state happens.

[1] testing/web-platform/meta/webauthn/__dir__.ini

Comment 1

[Andrew McCreight [:mccr8]]

James, do you have time to look at this in the next week? If not, I can try my hand at it.

Comment 2

[James Graham [:jgraham]]

Attachment: Bug 1507550 - Scrub out junk from rust signatures when processing LSAN data,

Rust signatures aren't properly demangled, and contain some trailing
data that seems to depend on the compiler version. This defeats the
attempt to allow LSAN errors when importing tests, and we end up
adding multiple variants of the same symbol to the allow list.

To avoid this, simply preprocess the symbols not to contain the
trailing junk when reading LSAN output, whilst we await better
demangling.

Comment 3

[Andrew McCreight [:mccr8]]

Thanks for working on this.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/6beca6ad237e
Scrub out junk from rust signatures when processing LSAN data, r=mccr8
https://hg.mozilla.org/integration/mozilla-inbound/rev/4700d8714486
Fixup existing LSAN allowed rules to match new behaviour, a=testonly

Comment 5

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/6beca6ad237e
https://hg.mozilla.org/mozilla-central/rev/4700d8714486