NetBSD Problem Report #60925

From oster@fween.ca  Sun Oct 25 21:21:53 2026
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Date: Sun, 25 Oct 2026 15:14:30 -0600 (CST)
From: oster@netbsd.org
Reply-To: oster@netbsd.org
To: gnats-bugs@NetBSD.org
Subject: named and cmake dump core in 10.2_STABLE amd64 after pthread_atfork.c changes
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X-From4GNATS: "oster@netbsd.org via gnats" <gnats-admin@NetBSD.org>

>Number:         60925
>Category:       lib
>Synopsis:       named and cmake dump core in 10.2_STABLE amd64 after pthread_atfork.c changes
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    martin
>State:          analyzed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Oct 25 21:25:00 +0000 2026
>Closed-Date:    
>Last-Modified:  Mon Oct 26 03:32:50 +0000 2026
>Originator:     Greg Oster
>Release:        NetBSD 10.2_STABLE
>Organization:

>Environment:


System: NetBSD pepe 10.1_STABLE NetBSD 10.1_STABLE (GENERIC) #0: Mon Sep 7 09:22:42 CST 2026 oster@gonzo:/u1/builds/build451/src/obj/amd64/u1/builds/build451/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:
   With today's NetBSD 10.2_STABLE checkout, cmake dumps core when running the bootstrap version
of cmake when trying to build cmake in pkgsrc.  The stack trace looks, in part, like:

#0  0x000076728c57f79a in _lwp_kill () from /usr/lib/libc.so.12
#1  0x000076728c584fa0 in abort () from /usr/lib/libc.so.12
#2  0x000076728e2220fa in uv__signal_global_init () at src/unix/signal.c:73
#3  0x000076728bc07cb6 in pthread_once () from /usr/lib/libpthread.so.1
#4  0x000076728e21dc0b in uv_once (guard=guard@entry=0x76728e42cb00 <uv.signal_global_init_guard>, 
    callback=callback@entry=0x76728e21a99d <uv__signal_global_init>) at src/unix/thread.c:454
#5  0x000076728e21aa1c in uv__signal_global_once_init () at src/unix/signal.c:111
#6  0x000076728e216d8a in uv_loop_init (loop=0x76728eca8000) at src/unix/loop.c:83
#7  0x00000000e078dcd1 in cmUVProcessChain::InternalData::Prepare(cmUVProcessChainBuilder const*) ()
 ...

  Within the same environment, named also dumps core, with the following stack trace:
Program terminated with signal SIGABRT, Aborted.
#0  0x000071db8af7f79a in _lwp_kill () from /usr/lib/libc.so.12
(gdb) where
#0  0x000071db8af7f79a in _lwp_kill () from /usr/lib/libc.so.12
#1  0x000071db8af84fa0 in abort () from /usr/lib/libc.so.12
#2  0x000071db9046d115 in ?? () from /usr/lib/libisc.so.21
#3  0x000071db8ec07cb6 in pthread_once () from /usr/lib/libpthread.so.1
#4  0x000071db90464e55 in uv_once () from /usr/lib/libisc.so.21
#5  0x000071db9045c26d in uv_loop_init () from /usr/lib/libisc.so.21
#6  0x000071db9043604d in isc.netmgr_create () from /usr/lib/libisc.so.21
#7  0x000071db904229b8 in isc_managers_create () from /usr/lib/libisc.so.21
#8  0x0000000095a666f2 in main ()
(gdb) 

This is replicated both on a full 10.2_STABLE install in userland (for named) on two
separate hosts, and in a 10.2_STABLE chroot (both with 10.1_STABLE and 10.2_STABLE kernels) for cmake.

>How-To-Repeat:
     Upgrade from 10.1_STABLE to today's 10.2_STABLE.  Run '/etc/rc.d/named onestart'.  Watch named fail to start
and dump core (if enabled).  Attempt to compile /usr/pkgsrc/devel/cmake in a 10.2_STABLE virtual environment.
Watch it also fail and dump core.

Note that the problem does not exist in the official 10.2 release.  It is only in 10.2_STABLE.

>Fix:
     Reverting this commit:

cvs rdiff -u -r1.17 -r1.17.2.1 src/lib/libc/gen/pthread_atfork.c

gets things working for me.  But no idea as to the underlying issue.

>Release-Note:

>Audit-Trail:
From: mlelstv@serpens.de (Michael van Elst)
To: gnats-bugs@netbsd.org
Cc: 
Subject: Re: lib/60925: named and cmake dump core in 10.2_STABLE amd64 after pthread_atfork.c changes
Date: Sun, 25 Oct 2026 23:44:25 -0000 (UTC)

 gnats-admin@NetBSD.org ("oster@netbsd.org via gnats") writes:

 >     Reverting this commit:
 >cvs rdiff -u -r1.17 -r1.17.2.1 src/lib/libc/gen/pthread_atfork.c
 >gets things working for me.  But no idea as to the underlying issue.


 -       return malloc(sizeof(atfork_builtin));
 +       rv = mmap(0, sizeof(atfork_builtin), PROT_READ|PROT_WRITE, MAP_PRIVATE,
 +           -1, 0);


 Shouldn't that be    MAP_ANON | MAP_PRIVATE   ?


From: Greg Oster <oster@netbsd.org>
To: gnats-bugs@netbsd.org, lib-bug-people@netbsd.org, gnats-admin@netbsd.org,
 netbsd-bugs@netbsd.org, oster@netbsd.org
Cc: 
Subject: Re: lib/60925: named and cmake dump core in 10.2_STABLE amd64 after
 pthread_atfork.c changes
Date: Sun, 25 Oct 2026 20:07:40 -0600

 On 2026-10-25 17.45, Michael van Elst via gnats wrote:
 > The following reply was made to PR lib/60925; it has been noted by GNATS.
 > 
 > From: mlelstv@serpens.de (Michael van Elst)
 > To: gnats-bugs@netbsd.org
 > Cc:
 > Subject: Re: lib/60925: named and cmake dump core in 10.2_STABLE amd64 after pthread_atfork.c changes
 > Date: Sun, 25 Oct 2026 23:44:25 -0000 (UTC)
 > 
 >   gnats-admin@NetBSD.org ("oster@netbsd.org via gnats") writes:
 >   
 >   >     Reverting this commit:
 >   >cvs rdiff -u -r1.17 -r1.17.2.1 src/lib/libc/gen/pthread_atfork.c
 >   >gets things working for me.  But no idea as to the underlying issue.
 >   
 >   
 >   -       return malloc(sizeof(atfork_builtin));
 >   +       rv = mmap(0, sizeof(atfork_builtin), PROT_READ|PROT_WRITE, MAP_PRIVATE,
 >   +           -1, 0);
 >   
 >   
 >   Shouldn't that be    MAP_ANON | MAP_PRIVATE   ?
 I tested starting /usr/sbin/named with pthread_atfork.c build with 
 "MAP_ANON | MAP_PRIVATE" instead, and it worked fine!

 Later...

 Greg Oster


Responsible-Changed-From-To: lib-bug-people->martin
Responsible-Changed-By: riastradh@NetBSD.org
Responsible-Changed-When: Mon, 26 Oct 2026 03:32:50 +0000
Responsible-Changed-Why:
This arose from an incomplete pullup-10 #1380:
https://releng.netbsd.org/cgi-bin/req-10.cgi?show=1380


State-Changed-From-To: open->analyzed
State-Changed-By: riastradh@NetBSD.org
State-Changed-When: Mon, 26 Oct 2026 03:32:50 +0000
State-Changed-Why:
problem analyzed


>Unformatted:

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