FreeBSD Errata Notice FreeBSD-EN-25:09.libc
2 July, 2025 by errata-notices@freebsd.org | freebsd
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FreeBSD-EN-25:09.libc Errata Notice
The FreeBSD Project
Topic: Dynamically-loaded C++ libraries crashing at exit
Category: core
Module: libc
Announced: 2025-07-02
Affects: FreeBSD 13.5 and FreeBSD 14.2
Corrected: 2025-04-17 01:01:36 UTC (stable/14, 14.2-STABLE)
2025-07-02 18:28:08 UTC (releng/14.2, 14.2-RELEASE-p4)
2025-04-17 01:02:12 UTC (stable/13, 13.5-STABLE)
2025-07-02 18:28:28 UTC (releng/13.5, 13.5-RELEASE-p2)
For general information regarding FreeBSD Errata Notices and Security
Advisories, including descriptions of the fields above, security
branches, and the following sections, please visit
<URL:https://security.FreeBSD.org/>.
I. Background
In C++, global objects' destructors are called at unload or exit time.
Global objects may be created either as objects in a global scope, or as
objects in a function scope declared with the `static` keyword.
II. Problem Description
Object destructors can create further global objects through the second
mechanism described above, function-scoped objects with the `static` keyword.
Creation of these objects adds more destructors that should be called at
unload or exit time while the application is already in the middle of
processing those destructors in reverse order from when they're added. As a
result, these newly added destructors are not called at unload time when the
C++ library has been loaded dynamically via dlopen() and subsequently
unloaded with dlclose().
III. Impact
The destructors that are not called at unload time are later attempted to be
called when the program exits, which may result in a crash as the library's
code has already been unmapped from the program's address space.
IV. Workaround
No workaround is available. C++ libraries that do not create more objects in
destructors are not affected.
V. Solution
Upgrade your system to a supported FreeBSD stable or release / security
branch (releng) dated after the correction date and restart any affected
services, or reboot the system.
Perform one of the following:
1) To update your system via a binary patch:
Systems running a RELEASE version of FreeBSD on the amd64 or arm64 platforms,
or the i386 platform on FreeBSD 13, can be updated via the freebsd-update(8)
utility:
# freebsd-update fetch
# freebsd-update install
2) To update your system via a source code patch:
The following patches have been verified to apply to the applicable
FreeBSD release branches.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# fetch https://security.FreeBSD.org/patches/EN-25:09/libc.patch
# fetch https://security.FreeBSD.org/patches/EN-25:09/libc.patch.asc
# gpg --verify libc.patch.asc
b) Apply the patch. Execute the following commands as root:
# cd /usr/src
# patch < /path/to/patch
c) Recompile the operating system using buildworld and installworld as
described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>.
Restart all daemons that use the library, or reboot the system.
VI. Correction details
This issue is corrected as of the corresponding Git commit hash in the
following stable and release branches:
Branch/path Hash Revision
- -------------------------------------------------------------------------
stable/14/ c43ae65b4b89 stable/14-n271080
releng/14.2/ 89a2823e17e5 releng/14.2-n269525
stable/13/ 04f7496f89e2 stable/13-n259249
releng/13.5/ f936833911d7 releng/13.5-n259167
- -------------------------------------------------------------------------
Run the following command to see which files were modified by a
particular commit:
# git show --stat <commit hash>
Or visit the following URL, replacing NNNNNN with the hash:
<URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN>
To determine the commit count in a working tree (for comparison against
nNNNNNN in the table above), run:
# git rev-list --count --first-parent HEAD
VII. References
<URL:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id(5870>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-25:09.libc.asc>
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