Messages in this thread | | | Date | Thu, 27 Aug 2009 11:34:41 +0200 | From | Oleg Nesterov <> | Subject | Re: mmotm 2009-08-24-16-24 uploaded |
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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?
When the child (2713) exits and the parent hangs, could you send me the content of /proc/parent_pid/status?
OK, suppose that due to the patch above we lost the notification. But, wait4 returns -ECHILD, who reaped this child???
What does "$ ps CHILD_PID" say? /proc/child_pid/status please?
Oleg.
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