Crash in info 7.0.1

[Mark Laws]

Hi,

To reproduce, simply run "info --index-search=nh groff" using info from
texinfo 7.0.1 and the info pages from groff 1.22.4.  info will
initialize the terminal, then the following will appear at the bottom
row:

> Found 'nh' in Request Index. (',' tries to find next.)

followed immediately by a message from inside glibc:

> malloc(): unsorted double linked list corrupted

Backtrace:

(gdb) bt full
#0  0x00007f7c7342064c in ?? () from /usr/lib/libc.so.6
No symbol table info available.
#1  0x00007f7c733d0958 in raise () from /usr/lib/libc.so.6
No symbol table info available.
#2  0x00007f7c733ba53d in abort () from /usr/lib/libc.so.6
No symbol table info available.
#3  0x00007f7c734147ee in ?? () from /usr/lib/libc.so.6
No symbol table info available.
#4  0x00007f7c7342a3dc in ?? () from /usr/lib/libc.so.6
No symbol table info available.
#5  0x00007f7c7342d78c in ?? () from /usr/lib/libc.so.6
No symbol table info available.
#6  0x00007f7c7342e732 in malloc () from /usr/lib/libc.so.6
No symbol table info available.
#7  0x0000560aa10b6e2e in xmalloc (s=s@entry=48) at xmalloc.c:45
No locals.
#8  0x0000560aa10a3fe3 in info_new_reference (nodename=0x0, filename=0x0) at 
scan.c:365
        r = <optimized out>
        r = <optimized out>
#9  scan_node_contents (node=node@entry=0x560aa24247f0, 
fb=fb@entry=0x560aa22c1730, tag_ptr=tag_ptr@entry=0x560aa237ee78) at scan.c:1560
        in_parentheses = 0
        entry = <optimized out>
        in_menu = 0
        match = 0x7f7c7331d864 "*note Environments::).\n\n     A negative 
argument resets the hyphenation margin to zero, emitting\n     a warning of 
type 'range'.\n\n     The current hyphenation margin is available in the '.hym' 
read-on"...
        refs = 0x560aa2424a90
        refs_index = 4
        refs_slots = 7
        in_index = 0
#10 0x0000560aa10a2427 in info_node_of_tag_ext (fb=fb@entry=0x560aa22c1730, 
tag_ptr=0x560aa237ee78, fast=fast@entry=0) at nodes.c:1289
        tag = 0x560aa2359690
        node = 0x560aa24247f0
        is_anchor = 0
        anchor_tag = <optimized out>
        node_pos = <optimized out>
        anchor_pos = <optimized out>
        parent = <optimized out>
        subfile = <optimized out>
#11 0x0000560aa10a2735 in info_node_of_tag (tag_ptr=<optimized out>, 
fb=0x560aa22c1730) at nodes.c:1329
No locals.
#12 0x0000560aa10a289b in info_get_node_with_defaults (filename_in=<optimized 
out>,
    nodename_in=nodename_in@entry=0x560aa239b350 "Manipulating Hyphenation", 
defaults=<optimized out>) at nodes.c:996
        node = 0x0
        file_buffer = <optimized out>
        filename = 0x560aa2423ac0 "groff"
        nodename = 0x560aa2414740 "Manipulating Hyphenation"
#13 0x0000560aa10aac31 in info_select_reference (window=0x560aa241bc70, 
entry=entry@entry=0x560aa239b380) at session.c:2066
        node = <optimized out>
        file_system_error = 0x0
        filename = <optimized out>
        nodename = 0x560aa239b350 "Manipulating Hyphenation"
        label = 0x560aa239b330 "nh"
        line_number = 94
#14 0x0000560aa109333f in main (argc=<optimized out>, argv=<optimized out>) at 
info.c:1028
        result = 0x560aa239b380
        i = 106
        match_offset = 0
        initial_fb = <optimized out>
        getopt_long_index = 7
        init_file = 0x0
        error = 0x0

Sincerely,
Mark Laws

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