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

["Taylor R Campbell via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR bin/60472; it has been noted by GNATS.

From: Taylor R Campbell <riastradh%NetBSD.org@localhost>
To: tron%zhadum.org.uk@localhost
Cc: gnats-bugs%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, ryoon%NetBSD.org@localhost
Subject: Re: bin/60472: ld.elf_so(1) changes cause a segmentation fault in dlopen(3)
Date: Mon, 20 Jul 2026 19:05:31 +0000

 > Date: Mon, 20 Jul 2026 18:45:18 +0000 (UTC)
 > From: riastradh%NetBSD.org@localhost
 >=20
 > 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=3Dname@entry=3D0x7f7fff6e3940 "/usr/pkg/lib/dri/tls/swrast_dri.so",
     refobj=3Drefobj@entry=3D0x74cccaeb3000, flags=3Dflags@entry=3D9,
     mask=3Dmask@entry=3D0x7f7fff6e38b0) at /usr/src/libexec/ld.elf_so/searc=
 h.c:197
 197             assert(obj->refcount > 0);
 [Current thread is 1 (process 3675)]
 (gdb) bt
 #0  0x00007f7ff7ac580a in _rtld_load_library (
     name=3Dname@entry=3D0x7f7fff6e3940 "/usr/pkg/lib/dri/tls/swrast_dri.so",
     refobj=3Drefobj@entry=3D0x74cccaeb3000, flags=3Dflags@entry=3D9,
     mask=3Dmask@entry=3D0x7f7fff6e38b0) at /usr/src/libexec/ld.elf_so/searc=
 h.c:197
 #1  0x00007f7ff7ac2c4e in dlopen (
     name=3D0x7f7fff6e3940 "/usr/pkg/lib/dri/tls/swrast_dri.so", mode=3D258)
     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+=3D	-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>.