Bug 108669

Summary:	driOpenDriver uses RTLD_GLOBAL and breaks clang's libc++
Product:	Mesa	Reporter:	stsp2
Component:	Mesa core	Assignee:	mesa-dev
Status:	RESOLVED MOVED	QA Contact:	mesa-dev
Severity:	normal
Priority:	medium
Version:	18.0
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description stsp2 2018-11-06 00:37:12 UTC

driOpenDriver() does this:
handle = dlopen(realDriverName, RTLD_NOW | RTLD_GLOBAL)
When "realDriveName" == "radeonsi", we get libstdc++
loaded, because:

$ ldd /usr/lib64/dri/radeonsi_dri.so | grep libstdc++
libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f2b2ee30000)

So this dri driver is linked with libstdc++.
RTLD_GLOBAL makes a problem when the main program
or some other lib is built with clang's libc++.
There happens to be a mix of symbols with same name,
and an imminent, hard to debug crash.
Please use RTLD_LOCAL to avoid the problem.

I've found this patch:
https://lists.freedesktop.org/archives/mesa-commit/2014-June/050035.html
which reverts to RTLD_GLOBAL in 3 places.
The problem is described here:
https://lists.freedesktop.org/archives/mesa-dev/2014-May/060441.html
Based on that description, I think it was enough
to use RTLD_GLOBAL only for "libGL.so.1", leaving
other places with RTLD_LOCAL.

Comment 1 GitLab Migration User 2019-09-18 20:27:27 UTC

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