843940 - Valgrind warns about jumps due to an uninitialized member in mozilla::layers::Transaction that lacks a constructor

Status: RESOLVED FIXED

(Core :: Widget, defect)

Description

[Ben Turner (not reading bugmail, use the needinfo flag!)]

Bug 776217 added an mTargetRotation member to mozilla::layers::Transaction and never initialized it. Valgrind warns that we're making decisions based on that uninitialized value.

==18180== Conditional jump or move depends on uninitialised value(s)
==18180==    at 0x62647B7: mozilla::layers::ShadowLayerForwarder::BeginTransaction(nsIntRect const&, mozilla::ScreenRotation, nsIntRect const&, unsigned int) (ShadowLayers.cpp:51)
==18180==    by 0x623A548: mozilla::layers::BasicShadowLayerManager::BeginTransactionWithTarget(gfxContext*) (BasicLayerManager.cpp:1108)
==18180==    by 0x5748664: PresShell::Paint(nsView*, nsRegion const&, unsigned int) (nsPresShell.cpp:5391)
==18180==    by 0x5A499B9: nsViewManager::ProcessPendingUpdatesForView(nsView*, bool) (nsViewManager.cpp:400)
==18180==    by 0x5A49ABA: nsViewManager::WillPaintWindow(nsIWidget*) (nsViewManager.cpp:621)
==18180==    by 0x5A48008: nsView::WillPaintWindow(nsIWidget*) (nsView.cpp:960)
==18180==    by 0x5F0C72A: mozilla::widget::PuppetWidget::Paint() (PuppetWidget.cpp:552)
==18180==    by 0x5F0C8B5: mozilla::widget::PuppetWidget::PaintTask::Run() (PuppetWidget.cpp:594)
==18180==    by 0x61D0261: nsThread::ProcessNextEvent(bool, bool*) (nsThread.cpp:627)
==18180==    by 0x61A2C1D: NS_ProcessNextEvent_P(nsIThread*, bool) (nsThreadUtils.cpp:238)
==18180==    by 0x5FB0626: mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) (MessagePump.cpp:82)
==18180==    by 0x61F2F5B: MessageLoop::Run() (message_loop.cc:208)

Comment 1

[Nick Cameron [:nrc]]

The offending branch was only added in bug 796722.

Comment 2

[Nick Cameron [:nrc]]

Attachment: initialise mTargetRotation

Comment 3

[Nick Cameron [:nrc]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/e615a1f50311

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/e615a1f50311