bin/102834: /usr/bin/mail hangs on the sigsuspend system call in popen.c

[Andreas Longwitz]

>Number:         102834
>Category:       bin
>Synopsis:       /usr/bin/mail hangs on the sigsuspend system call in popen.c
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Sep 03 21:00:39 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Andreas Longwitz
>Release:        FreeBSD 6.1
>Organization:
Data Service Stockelsdorf, Germany
>Environment:
FreeBSD loserver.longwitz 6.1-RELEASE FreeBSD 6.1-RELEASE #0: Tue May 23 22:16:05 CEST 2006 root at loserver.longwitz:/usr/src/sys/i386/compile/LOSERVER  i386

>Description:
Sometimes the command /usr/bin/mail -s subject mailadr hangs on the sigsuspend system call in popen.c. This happens when the function findchild() running from wait_child() is interrupted by sigchild() running findchild() again. This happens when the child started just before exits too quickly.
>How-To-Repeat:

>Fix:
In popen.c (functions free_child() and wait_child()) the line
    struct child *cp = findchild(pid);
must be moved after the 3 sigfunction-calls.

>Release-Note:
>Audit-Trail:
>Unformatted: