llvm dev - Apr 2019 - LLD WASM linker has a deadlock race condition bug

Greetings,

I would like to bring attention to this bug report:
https://bugs.llvm.org/show_bug.cgi?id=41508

WebAssembly is getting quite some attention in the 8.0.0 release cycle
of LLVM thanks to the target being promoted to non-experimental.
Consequently the WASM linker code in LLD is getting some more broad testing.

In the Zig frontend I've added --no-threads for now, to work around the bug.

Please let me know if there is more information I can provide to help
diagnose and fix this bug in LLD. The repro case I uploaded in the issue
tracker triggers the deadlock about 1 in 6 times for me.

Regards,
Andrew

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20190416/dbbeae63/attachment.sig>

Hi Andrew,

I replied to you on the bug report thread. A suspicious thing I found in
lld/wasm is that it calls parallelForEach from a callback function of
parallelForEach, although that function is not reentrant.

On Tue, Apr 16, 2019 at 4:35 PM Andrew Kelley via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Greetings,
>
> I would like to bring attention to this bug report:
> https://bugs.llvm.org/show_bug.cgi?id=41508
>
> WebAssembly is getting quite some attention in the 8.0.0 release cycle
> of LLVM thanks to the target being promoted to non-experimental.
> Consequently the WASM linker code in LLD is getting some more broad
> testing.
>
> In the Zig frontend I've added --no-threads for now, to work around the
> bug.
>
> Please let me know if there is more information I can provide to help
> diagnose and fix this bug in LLD. The repro case I uploaded in the issue
> tracker triggers the deadlock about 1 in 6 times for me.
>
> Regards,
> Andrew
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20190416/60aac886/attachment.html>