Bug #14

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

Added by skrueger over 8 years ago. Updated almost 8 years ago.

Status:ClosedStart date:
Priority:NormalDue date:
Assignee:-% Done:

0%

Category:-
Target version:-

Description

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?

History

#1 Updated by dillon over 8 years ago

: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
Matthew Dillon
<>

#2 Updated by skrueger over 8 years ago

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

#3 Updated by dillon over 8 years ago

:..
:> 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

Right. The mpsafe sysctls are experimental. I put them in there so
we could start identifying areas that need work, and we've identified
probably half a dozen issues so far. They aren't turned on by default
and so will not effect the release. The areas in question, along with
other goodies, are going to be worked on after the release.

In the case of fstat the issue is simply the process p_lock counter
being accessed without appropriate MP protection.

-Matt
Matthew Dillon
<>

#4 Updated by corecode almost 8 years ago

is this fixed?

#5 Updated by dillon almost 8 years ago

:Simon 'corecode' Schubert <> added the comment:
:
:is this fixed?

I think this one is fixed. Hopefully all the lockf related bugs have
been fixed now.

-Matt
Matthew Dillon
<>

#6 Updated by skrueger almost 8 years ago

sry for replying so late

yes this bug is fixed and the issue can be closed

thx

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