bug#27668: 26.0.50; Crash with display-line-numbers t

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Date: Thu, 13 Jul 2017 20:17:51 +0200
> 
> (gdb) p  it->glyph_row->used[TEXT_AREA]
> $1 = 66
> 
> (gdb) bt
> #0  terminate_due_to_signal (sig=sig@entry=6, 
> backtrace_limit=backtrace_limit@entry=2147483647) at emacs.c:363
> #1  0x00000000005a5084 in die (msg=msg@entry=0x6987d8 "pdl->kind == 
> SPECPDL_BACKTRACE", file=file@entry=0x698448 "eval.c", line=line@entry=150) 
> at alloc.c:7348
> #2  0x0000000000419f3b in backtrace_function (pdl=<optimized out>) at 
> eval.c:150
> #3  <function called from gdb>
> #4  maybe_produce_line_number (it=it@entry=0x7fffffff8130) at xdisp.c:21010
> #5  0x0000000000465365 in display_line (it=it@entry=0x7fffffff8130, 
> cursor_vpos=cursor_vpos@entry=16) at xdisp.c:21225
> #6  0x00000000004672bd in try_window (window=..., 
> window@entry=XIL(0x146d7d5), pos=..., flags=flags@entry=1) at xdisp.c:17544
> #7  0x000000000047f9ab in redisplay_window (window=XIL(0x146d7d5), 
> just_this_one_p=just_this_one_p@entry=false) at xdisp.c:16991
> #8  0x00000000004831fb in redisplay_window_0 (window=..., 
> window@entry=XIL(0x146d7d5)) at xdisp.c:14751

Curiouser and curiouser...

OK, in frame #5, the one in display_line, what do these produce:

  (gdb) p it->current
  (gdb) pgrowx it->glyph_row