zombie processes waiting for a lock, smth to worry about?

[Stefan Krüger]

Matthew Dillon wrote:
> :hi folks,
> :
> :sometimes sysctl or fstat just stop and end up as a zombie process
> :
> :% ps
> :  PID  TT  STAT      TIME COMMAND
> :   81 #C1  SL     0:00.04 _su -m (csh)
> :40884 #C1  IWL    0:00.00 sysctl
> :41510 #C1  DWL    0:00.00 sh -c /usr/bin/fstat > /dev/null 2>&1
> :41513 #C1  ZL     0:00.00 /usr/bin/fstat
> :53544 #C1  IWL    0:00.00 sysctl
> :53549 #C1  IWL    0:00.00 sysctl
> :53647 #C1  DL     0:00.01 sh -c /usr/bin/fstat > /dev/null 2>&1
> :53648 #C1  ZL     0:00.00 /usr/bin/fstat
> :53651 #C1  DL     0:00.02 sh -c /usr/bin/fstat > /dev/null 2>&1
> :53654 #C1  ZL     0:00.00 /usr/bin/fstat
> :57387 #C1  R1L+   0:00.01 ps
> :
> :I can't kill them, even with kill -9
> :
> :so my question is, ignore them or is smth broken?
> 
>     Well, fstat can seg-fault trying to access kernel memory.  The
>     question is why aren't these zombies being reaped by their parent.
> 
>     If you generate a kernel core dump with the system in this state
>     and upload it to leaf I'll try to track it down.
Matt suggested turning off the mpsafe sysctl's (they're turned off by
default) and this worked, no more zombie processes, no more strange
netstat -m output, no systat -ifstat errors