** Description changed: - We're encountering a critical issue in Qt 5.15.13 as shipped in Ubuntu - 24.04 (Noble). The Qt V4 JIT engine occasionally generates invalid - machine code, resulting in crashes at runtime. + [ Impact ] + We're encountering a critical issue in Qt 5.15.13 as shipped in Ubuntu 24.04 (Noble). The Qt V4 JIT engine occasionally generates invalid machine code, resulting in crashes at runtime. - This issue is tracked upstream as QTBUG-111935 [0], and was fixed in Qt + This issue is tracked upstream as + https://bugreports.qt.io/browse/QTBUG-111935, and was fixed in Qt 5.15.14. Symptoms: - * Application crashes with segmentation faults or illegal instruction errors when executing certain JavaScript in QML (GC). - * The issue appears to stem from bad register allocation or incorrect code paths during JIT compilation. + * Application crashes with segmentation faults or illegal instruction errors when executing certain JavaScript in QML (GC). + * The issue appears to stem from bad register allocation or incorrect code paths during JIT compilation. - Affected Package: - qtdeclarative-opensource-src version 5.15.13 in Ubuntu Noble + This affects users using Lomiri (and plasma) on arm64 (maybe others) + devices. It causes random crashes in normal day to day use, 100% with + QV4_MM_AGGRESSIVE_GC=1, never with QV4_FORCE_INTERPRETER=1. - Upstream Fix: + [ Test Plan ] + * Start plasmashell or lomiri with set QV4_MM_AGGRESSIVE_GC=1. - Commit that resolves the issue: + [ Where problems could occur ] + The fix touches the JIT interpreter code, so potential problems would occur there. - qt/qtdeclarative@3bd18f4 [1] or attached patch - JIT: Add missing {STORE|LOAD}_ACC() to CreateCallContext + However, we run upstream test suite during build, so it should catch any + potential regressions. - Would it be possible to Cherry-pick the above fix into the current Qt - 5.15.13 package in Noble? + [ Other Info ] + Upstream commit that resolves the issue: - I’m only able to apply a downstream patch for now, but would prefer a - shared fix in the official archive if feasible. - - Thanks for considering this! - - [0] https://bugreports.qt.io/browse/QTBUG-111935 - [1] https://github.com/qt/qtdeclarative/commit/3bd18f41cfb0f3da65eecf216e49a9bb6bda71a6 - - — Marius + https://code.qt.io/cgit/qt/qtdeclarative.git/commit/?id=3bd18f41cfb0f3da65eecf216e49a9bb6bda71a6
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2111216 Title: Qt V4 JIT engine generates bad JIT code To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qtdeclarative-opensource-src/+bug/2111216/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
