[Bug 292146] shells/mksh: Segmentation fault on RELESE-15.0

From: <bugzilla-noreply_at_freebsd.org>
Date: Sat, 03 Jan 2026 08:54:19 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=292146

            Bug ID: 292146
           Summary: shells/mksh: Segmentation fault on RELESE-15.0
           Product: Ports & Packages
           Version: Latest
          Hardware: amd64
                OS: Any
            Status: New
          Severity: Affects Some People
          Priority: ---
         Component: Individual Port(s)
          Assignee: ports-bugs@FreeBSD.org
          Reporter: h4ckee@proton.me
                CC: schaiba@gmail.com
                CC: schaiba@gmail.com
             Flags: maintainer-feedback?(schaiba@gmail.com)

Created attachment 266771
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=266771&action=edit
Build log

Hello!
I'm trying to build mksh-R59c on FreeBSD 15.0-RELEASE, but get Segmentation
faults. Could you please help me to find the issue amd mabybe fix it?

Below is when I run Build.sh manually:

    root@freebsd15:/usr/src/contrib/mksh # lldb /usr/src/contrib/mksh/mksh
    (lldb) target create "/usr/src/contrib/mksh/mksh"
    Current executable set to '/usr/src/contrib/mksh/mksh' (x86_64).
    (lldb) run
    Process 23012 launched: '/usr/src/contrib/mksh/mksh' (x86_64)
    Process 23012 stopped
    * thread #1, name = 'mksh', stop reason = signal SIGSEGV: address not
mapped to object (fault address: 0x62)
        frame #0: 0x0000000000230163 mksh`inittraps + 355
    mksh`inittraps:
    ->  0x230163 <+355>: cmpb   $0x0, (%rax)
        0x230166 <+358>: jne    0x230037       ; <+55>
        0x23016c <+364>: jmp    0x230020       ; <+32>
        0x230171 <+369>: movl   $0x0, 0x1fefd(%rip) ; sigtraps + 40
    (lldb) bt
    * thread #1, name = 'mksh', stop reason = signal SIGSEGV: address not
mapped to object (fault address: 0x62)
      * frame #0: 0x0000000000230163 mksh`inittraps + 355
        frame #1: 0x0000000000239d57 mksh`main + 599
        frame #2: 0x0000000821da037f libc.so.7`__libc_start1 + 303
        frame #3: 0x0000000000212004 mksh`_start at crt1_s.S:80
    (lldb)

Or sometimes I get (with disabled stack-protecrot and PIE+RELRO):

root@freebsd15:/usr/src/bin/mksh # lldb
/usr/obj/usr/src/amd64.amd64/bin/mksh/mksh.full
(lldb) target create "/usr/obj/usr/src/amd64.amd64/bin/mksh/mksh.full"
Current executable set to '/usr/obj/usr/src/amd64.amd64/bin/mksh/mksh.full'
(x86_64).
(lldb) run
Process 14406 launched: '/usr/obj/usr/src/amd64.amd64/bin/mksh/mksh.full'
(x86_64)
Process 14406 stopped
* thread #1, name = 'mksh.full', stop reason = signal SIGSEGV: address not
mapped to object (fault address: 0x1)
    frame #0: 0x0000279ed1831c0b mksh.full`inittraps at histrap.c:1114:28
   1111                 sigtraps[i].mess = NULL;
   1112 #endif
   1113                 if ((sigtraps[i].mess == NULL) ||
-> 1114                     (sigtraps[i].mess[0] == '\0'))
   1115                         sigtraps[i].mess = shf_smprintf(Tf_sd,
   1116                             "Signal", i);
   1117         }
(lldb) bt
* thread #1, name = 'mksh.full', stop reason = signal SIGSEGV: address not
mapped to object (fault address: 0x1)
  * frame #0: 0x0000279ed1831c0b mksh.full`inittraps at histrap.c:1114:28
    frame #1: 0x0000279ed183c28f mksh.full`main [inlined] main_init(argc=1,
argv=0x000027a6f1bbebc0, sp=<unavailable>, lp=<unavailable>) at main.c:352:2
    frame #2: 0x0000279ed183c039 mksh.full`main(argc=<unavailable>,
argv=<unavailable>) at main.c:738:12
    frame #3: 0x000027a6f3b6c37f libc.so.7`__libc_start1 + 303
    frame #4: 0x0000279ed18127e1 mksh.full`_start at crt1_s.S:80
(lldb)

When I build from ports I still get Segfault:

root@freebsd15:/usr/ports/shells/mksh # ll work/mksh/mksh
-rwxr-xr-x  1 root wheel uarch 362472 Jan  3 08:35 work/mksh/mksh*
root@freebsd15:/usr/ports/shells/mksh # file work/mksh/mksh
work/mksh/mksh: ELF 64-bit LSB executable, x86-64, version 1 (FreeBSD),
dynamically linked, interpreter /libexec/ld-elf.so.1, for FreeBSD 15.0
(1500068), FreeBSD-style, with debug_info, not stripped
root@freebsd15:/usr/ports/shells/mksh # work/mksh/mksh
Segmentation fault (core dumped)

Regards,
Sergey.

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