os-sunos/448: The 'root' httpd server process will block, the machine will respond very slowly, and refuse all connections.

[Josh Rabinowitz <jo...@stockmaster.com>]

>Number:         448
>Category:       os-sunos
>Synopsis:       The 'root' httpd server process will block, the machine will respond very slowly, and refuse all connections.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apache (Apache HTTP Project)
>State:          open
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Mon Apr 21 22:30:01 1997
>Originator:     joshr@stockmaster.com
>Organization:
apache
>Release:        1.2b8
>Environment:
SunOS 4.1.4, few patches, built with gcc.  On a Sparc IPX running
about 50,000 invokations of a nph- cgi daily.
>Description:
I have observed the server to seriously misbehave in the following way.
I have not tried to reproduce it.  
Symptoms:
1)  top display showed the root httpd process at the top of the
	display, but not spinning cpus,  
4083 root      32    0  372K  276K run    14:51  1.96%  1.95% httpd

2) When I attached to the same process with gdb: Attaching to program `/usr/local/etc/httpd/httpd', process 4083sendmail
Reading symbols from /usr/lib/libc.so.1.9.1...done.
Reading symbols from /usr/lib/libdl.so.1.0...done.
0xf7737300 in fork ()
(gdb) where
#0  0xf7737300 in fork ()
#1  0x5680 in make_child ()
#2  0x60e4 in standalone_main ()
#3  0x6438 in main ()
(gdb) c
Continuing. (...no return...)

3) Then I traced the process:
race -p process
wait4 (0, 0xf7fffc94, 0x1, 0) = 15139
getpid () = 4083
gettimeofday (0xf7fffb08, 0) = 0
getpid () = 4083
gettimeofday (0xf7fffb08, 0) = 0
fork () = 15140
- SIGCHLD (20)
wait4 (0, 0xf7fffc94, 0x1, 0) = 15140
getpid () = 4083
gettimeofday (0xf7fffb08, 0) = 0
getpid () = 4083
gettimeofday (0xf7fffb08, 0) = 0
fork () = 15141
- SIGCHLD (20)
wait4 (0, 0xf7fffc94, 0x1, 0) = 15141
>How-To-Repeat:
I have no idea. This only happens very occasionally 
(I catch it occurring, say, once a month)
>Fix:

>Audit-Trail:
>Unformatted: