Messages in this thread | | | Date | Thu, 27 Aug 2009 18:43:03 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: mmotm 2009-08-24-16-24 uploaded |
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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
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