Bug 2041942 - rust-brotli compression test failures caused by Rust 1.56+ / LLVM 13
Summary: rust-brotli compression test failures caused by Rust 1.56+ / LLVM 13
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: llvm
Version: 36
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Tom Stellard
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2022-01-18 15:13 UTC by Fabio Valentini
Modified: 2023-05-25 19:08 UTC (History)
14 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2023-05-25 19:08:05 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Github rust-lang rust pull 98567 0 None Merged Update llvm-project 2022-08-29 23:03:47 UTC

Description Fabio Valentini 2022-01-18 15:13:17 UTC
Description of problem:
Since rust was updated to version 1.56.0 in rawhide (which was the first version to use LLVM 13 instead of LLVM 12), the test suite in the brotli crate fails. This issue is still happening with Rust 1.58.0 in both Fedora Rawhide and 35.

Interestingly, the same failure does not happen on Fedora 34, where Rust is built against LLVM 12, so this only affects Rust 1.56+ WITH LLVM 13, but not with LLVM 12.

One of the unit tests in brotli (handling multithreaded compression) seems to return wrong results in some cases:

```
failures:
---- test_threading::multi_threaded_split_compression_test_4 stdout ----
thread 'test_threading::multi_threaded_split_compression_test_4' panicked at 'assertion failed: `(left == right)`
  left: `137602`,
 right: `136812`', src/bin/test_threading.rs:57:9
failures:
    test_threading::multi_threaded_split_compression_test_4
```

Version-Release number of selected component (if applicable):
rust-1.58.0-1.fc36
llvm-libs-13.0.0-6.fc36

How reproducible:
Always, on all tested architectures.

Steps to Reproduce:
1. fedpkg clone rust-brotli
2. cd rust-brotli
3. fedpkg mockbuild

Actual results:
One of the unit tests for multithreaded compression fails with unexpected result.

Expected results:
Unit test succeeds.

Additional info:
koschei has complete build logs for recent failed rust-brotli builds:
https://koschei.fedoraproject.org/package/rust-brotli?collection=f36

koschei log entry that shows when the first failure occurred:
https://koschei.fedoraproject.org/build/11391779

Comment 1 Ben Cotton 2022-02-08 21:10:26 UTC
This bug appears to have been reported against 'rawhide' during the Fedora 36 development cycle.
Changing version to 36.

Comment 2 Josh Stone 2022-08-29 22:31:45 UTC
Current versions of rust-brotli.spec have dropped the "brotli" binary, which is what included the "test_threading" module, so this hasn't been running anymore.

However, I just tried "cargo test --release" manually on the upstream sources, and it still fails with rust-1.63.0-1.fc36.x86_64 and llvm-libs-14.0.5-1.fc36.x86_64.

It does pass with upstream stable-1.63.0 (also LLVM 14.0.5).

Comment 3 Josh Stone 2022-08-29 23:03:47 UTC
It does not pass with upstream stable-1.62.0. I bisected that to rust#98567, which is an LLVM update nominally about AVR, but also includes a couple backports that @nikic added.

https://github.com/rust-lang/llvm-project/compare/d1ddc34c4b23468f6d2bf553084834b104e16dde...8b6b5014fdad3a750f7242a6bfdcad83619498d4

I'm guessing it's the SCEV patch that's relevant.

Comment 4 Ben Cotton 2023-04-25 16:47:39 UTC
This message is a reminder that Fedora Linux 36 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 36 on 2023-05-16.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '36'.

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Comment 5 Ludek Smid 2023-05-25 19:08:05 UTC
Fedora Linux 36 entered end-of-life (EOL) status on 2023-05-16.

Fedora Linux 36 is no longer maintained, which means that it
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