Re: bin/60472: ld.elf_so(1) changes cause a segmentation fault in dlopen(3)

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Mon, 20 Jul 2026 18:45:18 +0000 (UTC)
> From: riastradh%NetBSD.org@localhost
> 
> Can you please provide the stack trace from the core dump?

In particular, is it the same (for the part inside ld.elf_so) as this
stack trace that ryoon@ posted?

Core was generated by `firefox-bin'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007f7ff7ac580a in _rtld_load_library (
    name=name@entry=0x7f7fff6e3940 "/usr/pkg/lib/dri/tls/swrast_dri.so",
    refobj=refobj@entry=0x74cccaeb3000, flags=flags@entry=9,
    mask=mask@entry=0x7f7fff6e38b0) at /usr/src/libexec/ld.elf_so/search.c:197
197             assert(obj->refcount > 0);
[Current thread is 1 (process 3675)]
(gdb) bt
#0  0x00007f7ff7ac580a in _rtld_load_library (
    name=name@entry=0x7f7fff6e3940 "/usr/pkg/lib/dri/tls/swrast_dri.so",
    refobj=refobj@entry=0x74cccaeb3000, flags=flags@entry=9,
    mask=mask@entry=0x7f7fff6e38b0) at /usr/src/libexec/ld.elf_so/search.c:197
#1  0x00007f7ff7ac2c4e in dlopen (
    name=0x7f7fff6e3940 "/usr/pkg/lib/dri/tls/swrast_dri.so", mode=258)
    at /usr/src/libexec/ld.elf_so/rtld.c:1696
#2  0x000074ccb9d75b35 in loader_open_driver_lib () from /usr/pkg/lib/libGL.so

If so, it should be fixed by this commit:

https://mail-index.netbsd.org/source-changes/2026/07/20/msg163255.html


As a workaround, you can also comment out the line

src/libexec/ld.elf_so:CPPFLAGS+=	-DDEBUG

I enabled it in current the other day so we would shake out all the
bitrot in ld.elf_so assertions over the years to make them useful
again as a diagnostic measure, especially for chasing hard-to-find
race conditions like PR lib/59751: dlclose is not MT-safe depending on
the libraries unloaded <https://gnats.NetBSD.org/59751>.