Bug 15491

Summary:	segmentation fault in busybox/glibc due to CONFIG_STACK_OPTIMIZATION_386
Product:	buildroot	Reporter:	Felix Schmidt <fesc2000>
Component:	Other	Assignee:	unassigned
Status:	RESOLVED MOVED
Severity:	normal	CC:	buildroot, yann.morin.1998
Priority:	P5
Version:	2023.02
Target Milestone:	---
Hardware:	All
OS:	Linux
Host:	Embedded Atom CE2752	Target:	i686-buildroot-linux-gnu
Build:	Linux x86

Description Felix Schmidt 2023-03-25 21:10:12 UTC

Hi,

i was facing the issue that busybox (ls appled) was generating a random segmentation fault in libc/ctime() (i386 platform, glibc 2.30).
The actual problem was that CONFIG_STACK_OPTIMIZATION_386 was set by default, causing an 8 byte aligned stack, and glibc uses a movaps instruction on it (which requires 16 byte alignment).

Obviously i could solve this by disabling CONFIG_STACK_OPTIMIZATION_386, but it took me quite a while to find it out.

This really should be disabled by default. After some digging it seems that the ABI nowadays mandates 16 byte stack alignment even for i386 (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38496).

Comment 1 Thomas Petazzoni 2023-03-26 12:15:47 UTC

See also this patch and the discussion: https://patchwork.ozlabs.org/project/buildroot/patch/20230210233658.3763549-1-romain.naour@gmail.com/

Comment 2 Yann E. MORIN 2024-06-15 15:07:35 UTC

Thank you for your report.

The issue tracker for the Buildroot project has been moved to
the Gitlab.com issue tracker:
    https://gitlab.com/buildroot.org/buildroot/-/issues

We are taking this opportunity to close old issues in this old
tracker. If you believe your issue is still relevant, please
open one in the new issue tracker.

Thank you!