Re: [PATCH] Re: [RFC PATCH] namespaces: fix leak on fork() failure

From: Mike Galbraith
Date: Sat May 05 2012 - 02:08:28 EST

On Sat, 2012-05-05 at 07:56 +0200, Mike Galbraith wrote:
> On Fri, 2012-05-04 at 13:29 -0700, Eric W. Biederman wrote:
>
> > Shrug. I have skimmed through all of that code and I don't see anything
> > obvious. I guess it would take a few more data points to figure out
> > where we are sleeping for a jiffy or two while we are reaping children.

egrep 'synchronize|rcu_barrier' /trace

vsftpd-7981 [003] .... 577.164997: synchronize_sched <-switch_task_namespaces
vsftpd-7981 [003] .... 577.164998: _cond_resched <-synchronize_sched
vsftpd-7981 [003] .... 577.164998: wait_rcu_gp <-synchronize_sched
vsftpd-7982 [003] .... 577.166583: synchronize_sched <-switch_task_namespaces
vsftpd-7982 [003] .... 577.166583: _cond_resched <-synchronize_sched
vsftpd-7982 [003] .... 577.166584: wait_rcu_gp <-synchronize_sched
vsftpd-7983 [003] .... 577.167128: synchronize_sched <-switch_task_namespaces
vsftpd-7983 [003] .... 577.167129: _cond_resched <-synchronize_sched
vsftpd-7983 [003] .... 577.167129: wait_rcu_gp <-synchronize_sched
vsftpd-7980 [003] .... 577.167678: synchronize_sched <-switch_task_namespaces
vsftpd-7980 [003] .... 577.167679: _cond_resched <-synchronize_sched
vsftpd-7980 [003] .... 577.167679: wait_rcu_gp <-synchronize_sched
vsftpd-7984 [003] .... 577.168232: synchronize_sched <-switch_task_namespaces
vsftpd-7984 [003] .... 577.168232: _cond_resched <-synchronize_sched
vsftpd-7984 [003] .... 577.168233: wait_rcu_gp <-synchronize_sched
vsftpd-7979 [003] .... 577.168800: synchronize_sched <-switch_task_namespaces
vsftpd-7979 [003] .... 577.168800: _cond_resched <-synchronize_sched
vsftpd-7979 [003] .... 577.168801: wait_rcu_gp <-synchronize_sched
vsftpd-7985 [003] .... 577.169373: synchronize_sched <-switch_task_namespaces
vsftpd-7985 [003] .... 577.169373: _cond_resched <-synchronize_sched
vsftpd-7985 [003] .... 577.169373: wait_rcu_gp <-synchronize_sched
vsftpd-7986 [003] .... 577.169946: synchronize_sched <-switch_task_namespaces
vsftpd-7986 [003] .... 577.169947: _cond_resched <-synchronize_sched
vsftpd-7986 [003] .... 577.169947: wait_rcu_gp <-synchronize_sched
vsftpd-7987 [003] .... 577.170519: synchronize_sched <-switch_task_namespaces
vsftpd-7987 [003] .... 577.170519: _cond_resched <-synchronize_sched
vsftpd-7987 [003] .... 577.170519: wait_rcu_gp <-synchronize_sched
vsftpd-7978 [003] .... 577.171091: synchronize_sched <-switch_task_namespaces
vsftpd-7978 [003] .... 577.171091: _cond_resched <-synchronize_sched
vsftpd-7978 [003] .... 577.171091: wait_rcu_gp <-synchronize_sched
vsftpd-7977 [003] .... 577.171519: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.171519: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.171519: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.171519: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.171520: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.171520: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.171532: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.171532: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.171533: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.171691: rcu_barrier_callback <-__rcu_process_callbacks
vsftpd-7977 [003] .... 577.176443: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.176552: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.176552: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.176553: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.176553: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.176553: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.176554: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.176561: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.176561: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.176562: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.176730: rcu_barrier_callback <-__rcu_process_callbacks
vsftpd-7977 [003] .... 577.180448: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.180553: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.180553: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.180554: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.180554: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.180555: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.180555: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.180561: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.180562: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.180563: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.180767: rcu_barrier_callback <-__rcu_process_callbacks
vsftpd-7977 [003] .... 577.184450: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.184565: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.184566: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.184566: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.184566: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.184566: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.184567: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.184573: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.184573: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.184573: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.184733: rcu_barrier_callback <-__rcu_process_callbacks
vsftpd-7977 [003] .... 577.188430: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.188536: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.188536: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.188536: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.188536: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.188537: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.188537: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.188555: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.188555: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.188555: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.188715: rcu_barrier_callback <-__rcu_process_callbacks
vsftpd-7977 [003] .... 577.192421: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.192527: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.192527: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.192527: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.192527: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.192528: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.192528: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.192546: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.192546: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.192547: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.192731: rcu_barrier_callback <-__rcu_process_callbacks
ksoftirqd/3-16 [003] ..s. 577.192731: complete <-rcu_barrier_callback
vsftpd-7977 [003] .... 577.192750: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.192821: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.192821: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.192821: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.192821: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.192822: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.192822: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.192832: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.192833: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.192833: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.196559: rcu_barrier_callback <-__rcu_process_callbacks
ksoftirqd/3-16 [003] ..s. 577.196560: complete <-rcu_barrier_callback
vsftpd-7977 [003] .... 577.196571: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.196642: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.196642: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.196642: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.196642: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.196643: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.196643: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.196653: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.196654: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.196654: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.200577: rcu_barrier_callback <-__rcu_process_callbacks
ksoftirqd/3-16 [003] ..s. 577.200577: complete <-rcu_barrier_callback
vsftpd-7977 [003] .... 577.200589: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.200659: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.200659: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.200659: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.200659: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.200660: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.200660: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.200671: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.200671: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.200672: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.204548: rcu_barrier_callback <-__rcu_process_callbacks
ksoftirqd/3-16 [003] ..s. 577.204548: complete <-rcu_barrier_callback
vsftpd-7977 [003] .... 577.204559: mutex_unlock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.204630: rcu_barrier <-deactivate_locked_super
vsftpd-7977 [003] .... 577.204631: rcu_barrier_sched <-rcu_barrier
vsftpd-7977 [003] .... 577.204631: _rcu_barrier.isra.31 <-rcu_barrier_sched
vsftpd-7977 [003] .... 577.204631: mutex_lock <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.204631: __init_waitqueue_head <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.204631: on_each_cpu <-_rcu_barrier.isra.31
vsftpd-7977 [003] d... 577.204642: rcu_barrier_func <-on_each_cpu
vsftpd-7977 [003] d... 577.204642: call_rcu_sched <-rcu_barrier_func
vsftpd-7977 [003] .... 577.204643: wait_for_completion <-_rcu_barrier.isra.31
ksoftirqd/3-16 [003] ..s. 577.208511: rcu_barrier_callback <-__rcu_process_callbacks
ksoftirqd/3-16 [003] ..s. 577.208511: complete <-rcu_barrier_callback
vsftpd-7977 [003] .... 577.208523: mutex_unlock <-_rcu_barrier.isra.31


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