Text cursor hangs/freezes, 2 x backspace unfreezes

[Sebastian Kayser]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: solaris2.9
Compiler: /opt/studio/SOS12/SUNWspro/bin/cc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='solaris2.9' -DCONF_MACHTYPE='i386-pc-solaris2.9' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/opt/csw/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H -DSOLARIS   -I.  -I. -I./include -I./lib  
-I/opt/csw/include -xO3 -m32 -xarch=386 -xnorunpath
uname output: SunOS ray3 5.10 Generic_141445-09 i86pc i386 i86pc
Machine Type: i386-pc-solaris2.9

Bash Version: 4.1
Patch Level: 5
Release Status: release

Description:
I am using bash 4.1.5 on Solaris 10 x86 (binary from opencsw.org built on
Solaris 9) in an xterm 243. Every now and then the text cursor "freezes", i.e.
subsequent keyboard input doesn't show up. truss'ing the bash process shows
that it's still reading the keys, but it doesn't process/display them.

$ truss -p 26716
read(0, 0x08047534, 1)          (sleeping...)
read(0, " a", 1)                                = 1
read(0, " s", 1)                                = 1
read(0, " d", 1)                                = 1
read(0, " f", 1)                                = 1
read(0, "  ", 1)                                = 1
read(0, "  ", 1)                                = 1
read(0, "  ", 1)                                = 1
read(0, 0x08047534, 1)          (sleeping...)
read(0, " 1", 1)                                = 1
read(0, " 2", 1)                                = 1
read(0, " 3", 1)                                = 1
read(0, " 4", 1)                                = 1
read(0, 0x08047534, 1)          (sleeping...)

Hitting backspace twice "unfreezes" the cursor and everything is back to
normal. Previously entered characters don't show up, but new ones do.

...
read(0, "\b", 1)                                = 1
read(0, "\b", 1)                                = 1
write(2, "\b1B [ K", 4)                         = 4
read(0, 0x08047534, 1)          (sleeping...)
read(0, "  ", 1)                                = 1
write(2, "  ", 1)                               = 1
read(0, "  ", 1)                                = 1
...

The binary hasn't been built with debugging symbols. When the issue occurs, the
stack trace looks like below. The issue is nothing specifically new to 4.1.5,
I also ran into it with previous versions. Please let me know if you need any
additional information.

$ pstack core.26716
core 'core.26716' of 26716:     -bash
 fee09ff7 read     (0, 8047534, 1)
 080b8c21 rl_getc  (80f6dd8) + 1f
 080b8be7 rl_read_key (0, 804755c, 80aba46, 8047564, 80aba60, 8047570) + ad
 080ab914 readline_internal_char (8047564, 80aba60, 8047570, 80ab6fe, 808b5d6, 
8047580) + 5c
 080aba46 ???????? (8047570, 80ab6fe, 808b5d6, 8047580, 8067595, 8113e08)
 080aba60 ???????? (808b5d6, 8047580, 8067595, 8113e08, 8047770, 8047588)
 080ab6fe readline (8113e08) + 37
 08067595 ???????? (804759c, 8067d13, 0, 80475e0, 8047770, 80475b0)
 0806750d ???????? (0, 80475e0, 8047770, 80475b0, 806869c, 1)
 08067d13 ???????? (1)
 0806869c ???????? (0)
 0806825d ???????? (0, 0, 0, 80feea8, 0, 8102000)
 08065e05 yyparse  (0, 8047de8, 8065c7c, 0, 0, 0) + 12f
 08065bd9 parse_command (0, 0, 0, 0, 8047dfc, 80659f9) + 56
 08065c7c read_command (0, 0, 1, 8047e1c, 8064010, 8047e84) + 8c
 080659f9 reader_loop (8047e84, 8047e04, feffb818, 1, 0, 1) + dd
 08064010 main     (1, 8047e48, 8047e50) + 638
 08063942 ???????? (1, 8047eec, 0, 8047ef2, 8047eff, 8047f0f)


Repeat-By:
Sorry, couldn't yet narrow down how this issue can be triggered.