Hey,

release 1.13.1, running makewhatis /usr/share/man I get:

% gdb ./makewhatis
GNU gdb 6.1.1 [FreeBSD]
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This GDB was configured as "amd64-marcel-freebsd"...
(gdb) r /usr/share/man
Starting program: /home/uqs/ports/textproc/mdocml/work/mdocml-1.13.1/makewhatis /usr/share/man
[New LWP 101640]
[New Thread 801806400 (LWP 101640/makewhatis)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 801806400 (LWP 101640/makewhatis)]
0x0000000000410ba6 in post_it (mdoc=0x801819200) at mdoc_validate.c:1209
1209            lt = nbl->norm->Bl.type;
Current language:  auto; currently minimal
(gdb) bt
#0  0x0000000000410ba6 in post_it (mdoc=0x801819200) at mdoc_validate.c:1209
#1  0x000000000040e488 in rew_last (mdoc=0x801819200, to=0x802961240) at mdoc_macro.c:289
#2  0x000000000040e635 in rew_sub (t=<value optimized out>, mdoc=0x801819200, tok=<value optimized out>, line=<value optimized out>, ppos=<value optimized out>)
    at mdoc_macro.c:589
#3  0x000000000040c604 in blk_full (mdoc=0x801819200, tok=MDOC_Sh, line=610, ppos=1, pos=0x7fffffffd9a0, buf=0x80251e200 ".Sh RETURN VALUES") at mdoc_macro.c:1059
#4  0x000000000040a7a2 in mdoc_parseln (mdoc=0x801819200, ln=610, buf=0x80251e200 ".Sh RETURN VALUES", offs=1) at mdoc.c:886
#5  0x00000000004188fc in mparse_buf_r (curp=0x801817080, start=1) at read.c:565
#6  0x0000000000417da5 in mparse_parse_buffer (curp=0x801817080, file=<value optimized out>) at read.c:719
#7  0x00000000004180e0 in mparse_readfd (curp=0x801817080, fd=<value optimized out>, file=0x801b23100 "man9/callout_reset_on.9.gz") at read.c:765
#8  0x00000000004040ea in mpages_merge (mc=0x80181b058, mp=0x801817080) at mandocdb.c:1158
#9  0x0000000000403128 in main (argc=<value optimized out>, argv=<value optimized out>) at mandocdb.c:515
(gdb) f 0
#0  0x0000000000410ba6 in post_it (mdoc=0x801819200) at mdoc_validate.c:1209
1209            lt = nbl->norm->Bl.type;
(gdb) l
1204            nit = mdoc->last;
1205            if (MDOC_BLOCK != nit->type)
1206                    return(1);
1207    
1208            nbl = nit->parent->parent;
1209            lt = nbl->norm->Bl.type;
1210    
1211            switch (lt) {
1212            case LIST_tag:
1213                    /* FALLTHROUGH */
(gdb) p *nbl
$1 = {parent = 0x80183e840, child = 0x802961100, last = 0x0, next = 0x0, prev = 0x8024177e0, nchild = 2, line = 107, pos = 1, lastline = 378, tok = MDOC_Sh, flags = 24, 
  type = MDOC_BLOCK, sec = SEC_DESCRIPTION, norm = 0x0, prev_font = 0x0, args = 0x0, pending = 0x0, head = 0x802961100, body = 0x802961240, tail = 0x0, string = 0x0, 
  span = 0x0, eqn = 0x0, end = ENDBODY_NOT}
(gdb) 


Moving callout_reset_on.9 out of the way just makes it die at some other
section 9 manual. Good news however is that if I remove man9 altogether
it seemingly runs to completion. I'll attach the man-page in question,
hoping you'll be able to reproduce. Thanks!

Cheers,
Uli