bug#8821: 23.3; spins and eats up memory

[-1 <-1@0throot.com>]

While using emacs in text mode (-nw) on my remote machine (over SSH), I 
lost connectivity. When I logged in later, I found that the emacs, which 
I had left in the background, was spinning and had consumed all of the 
memory. The following gives a basic idea,

$ ps -opid,%cpu,%mem,rss,vsz,args -p `pgrep emacs`
   PID %CPU %MEM   RSS    VSZ COMMAND
31367 95.6 87.6 1807420 3138696 emacs

I first encountered this problem in 23.1 and I was able to confirm it in 
23.3 as well.

Following is the looping strace output,

$ strace -o /tmp/1 -p `pgrep emacs`
$ grep -v gettimeofday /tmp/1 | sort | uniq
brk(0xb7585000)                         = 0xb7564000
brk(0xb7589000)                         = 0xb7564000
ioctl(3, FIONREAD, [-1074857400])       = -1 EIO (Input/output error)
ioctl(3, SNDCTL_TMR_STOP or TCSETSW, {B0 -opost -isig -icanon -echo 
...}) = -1 EIO (Input/output error)
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfef13a8) = -1 EIO 
(Input/output error)
kill(31367, SIGHUP)                     = 0
mmap2(NULL, 1048576, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 
-1, 0) = -1 ENOMEM (Cannot allocate memory)
mmap2(NULL, 1048576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 
-1, 0) = -1 ENOMEM (Cannot allocate memory)
mmap2(NULL, 2097152, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 
-1, 0) = -1 ENOMEM (Cannot allocate memory)
rt_sigprocmask(SIG_BLOCK, [IO], [HUP TERM IO], 8) = 0
write(3, "\7", 1)                       = -1 EIO (Input/output error)

Following is the output from pstack,

$ pstack `pgrep emacs`
#1  0x00768e88 in mmap () from /lib/libc.so.6
#2  0x00701644 in new_heap () from /lib/libc.so.6
#3  0x00701e51 in arena_get2 () from /lib/libc.so.6
#4  0x007042c5 in malloc () from /lib/libc.so.6
#5  0x0816e843 in ?? ()
#6  0x0816f6c7 in ?? ()
#7  0x08185acb in ?? ()
#8  0x0813e7fe in ?? ()
#9  0x0813ec9d in ?? ()
#10 0x08141b13 in ?? ()
#11 0x08141b59 in ?? ()
#12 0x0807b0c0 in bind ()
#13 0x081a0616 in ?? ()
#14 0x081a2d3a in ?? ()
#15 0x08120ada in ?? ()
#16 0x08120c29 in ?? ()
#17 0x0818475c in ?? ()
#18 0x081208f5 in ?? ()
#19 0x08184821 in ?? ()
#20 0x08120971 in ?? ()
#21 0x08120d3b in ?? ()
#22 0x08120e62 in ?? ()
#23 0x081171fd in ?? ()
#24 0x006a8bb6 in __libc_start_main () from /lib/libc.so.6
#25 0x08054621 in bind ()

The following are the steps to reproduce the problem,

1. ssh localhost
2. emacs -nw
3. press CTRL-Z
4. press enter
5. disconnect by typing ~.
6. ps aux | grep emacs

Additional details,

$ uname -a
Linux lap.local 2.6.31.5-127.fc12.i686.PAE #1 SMP Sat Nov 7 21:25:57 EST 
2009 i686 i686 i386 GNU/Linux

$ cat /etc/redhat-release
Fedora release 12 (Constantine)

Lemme know if you need further details.

-- 
-1