Bug 2403472 - GCC may miscompile AutoBuffer which causes Firefox crashes on Fedora 43 only.
Summary: GCC may miscompile AutoBuffer which causes Firefox crashes on Fedora 43 only.
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: gcc
Version: 43
Hardware: Unspecified
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Jakub Jelinek
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-10-13 07:57 UTC by Martin Stransky
Modified: 2025-11-05 16:30 UTC (History)
16 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2025-11-05 16:30:01 UTC
Type: ---
Embargoed:

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Description Martin Stransky 2025-10-13 07:57:42 UTC 
Found upstream reports at https://bugzilla.mozilla.org/show_bug.cgi?id=1990430#c1

Firefox crash data at https://bugzilla.mozilla.org/show_bug.cgi?id=1990430 reports there are AutoBuffer array crashes on Fedora 43 only on all Firefox versions.

First crashes correlates with this GCC update: https://bodhi.fedoraproject.org/updates/FEDORA-2025-483b46505e 

This code may be wrongly align:
https://searchfox.org/firefox-main/rev/91e6069b9c1e7289d0c727b5110e144edc589204/xpcom/ds/nsTArray.h#2974


Reproducible: Always
Comment 1 Zephyr Lykos 2025-11-05 16:30:01 UTC 
This is not be a GCC issue.
see https://bugzilla.mozilla.org/show_bug.cgi?id=1990430, the dtor of AutoTArray is not compiler-provided, so it's not trivially copyable, thus UB.

Fix in upstream firefox.
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