lkml.org 
[lkml]   [2009]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: mmotm 2009-08-24-16-24 uploaded
On Thu, 27 Aug 2009 11:34:41 +0200
Oleg Nesterov <oleg@redhat.com> wrote:

> On 08/27, KAMEZAWA Hiroyuki wrote:
> >
> > On Thu, 27 Aug 2009 14:44:53 +0900
> > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> >
> > >
> > > In the newest mmotom, my S14nfslock hangs up. (x86-64/Fedora10)
> > >
> > > On Mon, 24 Aug 2009 16:28:30 -0700
> > > akpm@linux-foundation.org wrote:
> > >
> > > > ptrace-__ptrace_detach-do-__wake_up_parent-if-we-reap-the-tracee.patch
> > > > do_wait-wakeup-optimization-shift-security_task_wait-from-eligible_child-to-wait_consider_task.patch
> > >
> > > bisected. following 2 patches for filtering SIGCHLD cause hang (for my environ).
> > >
> > > > do_wait-wakeup-optimization-change-__wake_up_parent-to-use-filtered-wakeup.patch
> > > > do_wait-wakeup-optimization-change-__wake_up_parent-to-use-filtered-wakeup-selinux_bprm_committed_creds-use-__wake_up_parent.patch
>
> Confused. Which patch causes the hang? They should be applied in reverse order,
>
> do_wait-wakeup-optimization-change-__wake_up_parent-to-use-filtered-wakeup-selinux_bprm_committed_creds-use-__wake_up_parent.patch
> do_wait-wakeup-optimization-change-__wake_up_parent-to-use-filtered-wakeup.patch
>
> > removed S14nfslockd from rc5.d and check it by strace
> > ==
> > 2712] fstat(6, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
> > [pid 2712] mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc6f263c000
> > [pid 2712] dup(6) = 7
> > [pid 2712] write(6, "2712\n"..., 5) = 5
> > [pid 2712] close(6) = 0
> > [pid 2712] munmap(0x7fc6f263c000, 4096) = 0
> > [pid 2712] clone(Process 2713 attached
> > child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7fc6f2625780) = 2713
> > [pid 2712] wait4(2713, Process 2712 suspended
> > <unfinished ...>
> > ==
> > When process 2713 exits, process 2712 don't wake up.
>
> Hmm, very strange. How can I reproduce?
>
Sorry, I don't know.

But exited process's, but not caught, p->exit_signal was -1. (confirmed by printk)
(details in another mail)


> When the child (2713) exits and the parent hangs, could you send
> me the content of /proc/parent_pid/status?

Name: rpc.statd
State: S (sleeping)
Tgid: 2989
Pid: 2989
PPid: 2988
TracerPid: 2978
Uid: 0 0 0 0
Gid: 0 0 0 0
FDSize: 64
Groups: 0 1 2 3 4 6 10
VmPeak: 8204 kB
VmSize: 8200 kB
VmLck: 0 kB
VmHWM: 596 kB
VmRSS: 596 kB
VmData: 196 kB
VmStk: 84 kB
VmExe: 44 kB
VmLib: 1688 kB
VmPTE: 28 kB
Threads: 1
SigQ: 0/190743
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000011000
SigCgt: 0000000000004203
CapInh: 0000000000000000
CapPrm: fffffffffffffeff
CapEff: fffffffffffffeff
CapBnd: fffffffffffffeff
Cpus_allowed: ff
Cpus_allowed_list: 0-7
Mems_allowed: 00000000,00000001
Mems_allowed_list: 0
voluntary_ctxt_switches: 89
nonvoluntary_ctxt_switches: 1
Stack usage: 0 kB

>
> OK, suppose that due to the patch above we lost the notification.
> But, wait4 returns -ECHILD, who reaped this child???
>
Not sure.

> What does "$ ps CHILD_PID" say? /proc/child_pid/status please?
>
Can't get it. It seems reaped.
==
[root@bluextal mmotm-2.6.31-Aug27]# kill -s 0 2990(CHILD's pid)
bash: kill: (2990) - No such process


Thanks
-Kame



\
 
 \ /
  Last update: 2009-08-27 11:47    [W:0.096 / U:0.136 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site