Stream: git-wasmtime

Topic: wasmtime / Issue #1166 Determine cause of crash with infe...

view this post on Zulip Wasmtime GitHub notifications bot (Feb 03 2021 at 20:39):

bjorn3 commented on Issue #1166:

This is a bug with the old x86 backend.

view this post on Zulip Wasmtime GitHub notifications bot (Feb 03 2021 at 20:48):

cfallin closed Issue #1166:

Reported in https://github.com/bytecodealliance/cranelift/issues/1305 and fixed (by partially reverting a patch in https://github.com/bytecodealliance/cranelift/pull/1308), it appears that when brz and brnz are emitted with runtime-inferred REX prefixes (and therefore don't have constant instruction size), the code can jump into the middle of nowhere.

https://github.com/bytecodealliance/cranelift/pull/1308 changed brz and brnz back to using separate encodings for REX and non-REX to prevent crashes in the meantime. This issue is to find the cause and fix it.

STR are in https://github.com/bytecodealliance/cranelift/issues/1305 but I was not able to reproduce it locally.

Last updated: Dec 13 2025 at 21:03 UTC