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

From: Mike Galbraith
Date: Sat May 05 2012 - 01:56:06 EST

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.

GrimReaper meets SynchroZilla

vsftpd-7977 [003] .... 577.171463: sys_wait4 <-system_call_fastpath
vsftpd-7977 [003] .... 577.171463: do_wait <-sys_wait4
vsftpd-7977 [003] .... 577.171463: add_wait_queue <-do_wait
vsftpd-7977 [003] .... 577.171463: _raw_spin_lock_irqsave <-add_wait_queue
vsftpd-7977 [003] d... 577.171463: _raw_spin_unlock_irqrestore <-add_wait_queue
vsftpd-7977 [003] .... 577.171464: _raw_read_lock <-do_wait
vsftpd-7977 [003] .... 577.171464: wait_consider_task <-do_wait
vsftpd-7977 [003] .... 577.171464: wait_consider_task <-do_wait
vsftpd-7977 [003] .... 577.171464: wait_consider_task <-do_wait
vsftpd-7977 [003] .... 577.171465: __task_pid_nr_ns <-wait_consider_task
vsftpd-7977 [003] .... 577.171465: pid_nr_ns <-__task_pid_nr_ns
vsftpd-7977 [003] .... 577.171465: thread_group_times <-wait_consider_task
vsftpd-7977 [003] .... 577.171466: thread_group_cputime <-thread_group_times
vsftpd-7977 [003] .... 577.171466: task_sched_runtime <-thread_group_cputime
vsftpd-7977 [003] .... 577.171466: task_rq_lock <-task_sched_runtime
vsftpd-7977 [003] .... 577.171466: _raw_spin_lock_irqsave <-task_rq_lock
vsftpd-7977 [003] d... 577.171467: _raw_spin_lock <-task_rq_lock
vsftpd-7977 [003] d... 577.171467: _raw_spin_unlock_irqrestore <-task_sched_runtime
vsftpd-7977 [003] .... 577.171467: nsecs_to_jiffies <-thread_group_times
vsftpd-7977 [003] .... 577.171467: _raw_spin_lock_irq <-wait_consider_task
vsftpd-7977 [003] .... 577.171468: release_task <-wait_consider_task
vsftpd-7977 [003] .... 577.171468: proc_flush_task <-release_task
vsftpd-7977 [003] .... 577.171470: d_hash_and_lookup <-proc_flush_task
vsftpd-7977 [003] .... 577.171470: full_name_hash <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171470: d_lookup <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171470: __d_lookup <-d_lookup
vsftpd-7977 [003] .... 577.171471: d_hash_and_lookup <-proc_flush_task
vsftpd-7977 [003] .... 577.171471: full_name_hash <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171471: d_lookup <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171472: __d_lookup <-d_lookup
vsftpd-7977 [003] .... 577.171472: d_hash_and_lookup <-proc_flush_task
vsftpd-7977 [003] .... 577.171472: full_name_hash <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171472: d_lookup <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171473: __d_lookup <-d_lookup
vsftpd-7977 [003] .... 577.171473: d_hash_and_lookup <-proc_flush_task
vsftpd-7977 [003] .... 577.171473: full_name_hash <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171473: d_lookup <-d_hash_and_lookup
vsftpd-7977 [003] .... 577.171473: __d_lookup <-d_lookup
vsftpd-7977 [003] .... 577.171474: pid_ns_release_proc <-proc_flush_task
vsftpd-7977 [003] .... 577.171474: kern_unmount <-pid_ns_release_proc
vsftpd-7977 [003] .... 577.171474: mnt_make_shortterm <-kern_unmount
vsftpd-7977 [003] .... 577.171474: vfsmount_lock_global_lock_online <-mnt_make_shortterm
vsftpd-7977 [003] .... 577.171474: _raw_spin_lock <-vfsmount_lock_global_lock_online
vsftpd-7977 [003] .... 577.171475: vfsmount_lock_global_unlock_online <-mnt_make_shortterm
vsftpd-7977 [003] .... 577.171475: mntput <-kern_unmount
vsftpd-7977 [003] .... 577.171475: mntput_no_expire <-mntput
vsftpd-7977 [003] .... 577.171476: vfsmount_lock_local_lock <-mntput_no_expire
vsftpd-7977 [003] .... 577.171476: vfsmount_lock_global_lock_online <-mntput_no_expire
vsftpd-7977 [003] .... 577.171476: _raw_spin_lock <-vfsmount_lock_global_lock_online
vsftpd-7977 [003] .... 577.171476: mnt_get_count <-mntput_no_expire
vsftpd-7977 [003] .... 577.171477: vfsmount_lock_global_unlock_online <-mntput_no_expire
vsftpd-7977 [003] .... 577.171477: mnt_get_writers.isra.12 <-mntput_no_expire
vsftpd-7977 [003] .... 577.171477: __fsnotify_vfsmount_delete <-mntput_no_expire
vsftpd-7977 [003] .... 577.171477: fsnotify_clear_marks_by_mount <-__fsnotify_vfsmount_delete
vsftpd-7977 [003] .... 577.171478: _raw_spin_lock <-fsnotify_clear_marks_by_mount
vsftpd-7977 [003] .... 577.171478: dput <-mntput_no_expire
vsftpd-7977 [003] .... 577.171478: _raw_spin_lock <-dput
vsftpd-7977 [003] .... 577.171478: free_vfsmnt <-mntput_no_expire
vsftpd-7977 [003] .... 577.171478: kfree <-free_vfsmnt
vsftpd-7977 [003] .... 577.171479: __phys_addr <-kfree
vsftpd-7977 [003] .... 577.171479: __slab_free <-kfree
vsftpd-7977 [003] .... 577.171479: free_debug_processing <-__slab_free
vsftpd-7977 [003] d... 577.171479: check_slab <-free_debug_processing
vsftpd-7977 [003] d... 577.171479: slab_pad_check.part.42 <-check_slab
vsftpd-7977 [003] d... 577.171480: on_freelist <-free_debug_processing
vsftpd-7977 [003] d... 577.171480: check_object <-free_debug_processing
vsftpd-7977 [003] d... 577.171480: check_bytes_and_report <-check_object
vsftpd-7977 [003] d... 577.171480: check_bytes_and_report <-check_object
vsftpd-7977 [003] d... 577.171481: set_track <-free_debug_processing
vsftpd-7977 [003] d... 577.171481: dump_trace <-save_stack_trace
vsftpd-7977 [003] d... 577.171481: print_context_stack <-dump_trace
vsftpd-7977 [003] d... 577.171484: init_object <-free_debug_processing
vsftpd-7977 [003] .... 577.171485: _raw_spin_lock_irqsave <-__slab_free
vsftpd-7977 [003] d... 577.171485: _raw_spin_unlock_irqrestore <-__slab_free
vsftpd-7977 [003] .... 577.171485: mnt_free_id.isra.20 <-free_vfsmnt
vsftpd-7977 [003] .... 577.171485: _raw_spin_lock <-mnt_free_id.isra.20
vsftpd-7977 [003] .... 577.171486: free_percpu <-free_vfsmnt
vsftpd-7977 [003] .... 577.171486: _raw_spin_lock_irqsave <-free_percpu
vsftpd-7977 [003] d... 577.171486: pcpu_free_area <-free_percpu
vsftpd-7977 [003] d... 577.171487: pcpu_chunk_slot <-pcpu_free_area
vsftpd-7977 [003] d... 577.171487: pcpu_chunk_relocate <-pcpu_free_area
vsftpd-7977 [003] d... 577.171488: pcpu_chunk_slot <-pcpu_chunk_relocate
vsftpd-7977 [003] d... 577.171488: _raw_spin_unlock_irqrestore <-free_percpu
vsftpd-7977 [003] .... 577.171488: kmem_cache_free <-free_vfsmnt
vsftpd-7977 [003] .... 577.171488: __phys_addr <-kmem_cache_free
vsftpd-7977 [003] .... 577.171489: __slab_free <-kmem_cache_free
vsftpd-7977 [003] .... 577.171489: free_debug_processing <-__slab_free
vsftpd-7977 [003] d... 577.171489: check_slab <-free_debug_processing
vsftpd-7977 [003] d... 577.171489: slab_pad_check.part.42 <-check_slab
vsftpd-7977 [003] d... 577.171489: on_freelist <-free_debug_processing
vsftpd-7977 [003] d... 577.171490: check_object <-free_debug_processing
vsftpd-7977 [003] d... 577.171490: check_bytes_and_report <-check_object
vsftpd-7977 [003] d... 577.171490: check_bytes_and_report <-check_object
vsftpd-7977 [003] d... 577.171491: set_track <-free_debug_processing
vsftpd-7977 [003] d... 577.171491: dump_trace <-save_stack_trace
vsftpd-7977 [003] d... 577.171491: print_context_stack <-dump_trace
vsftpd-7977 [003] d... 577.171494: init_object <-free_debug_processing
vsftpd-7977 [003] .... 577.171495: deactivate_super <-mntput_no_expire
vsftpd-7977 [003] .... 577.171495: down_write <-deactivate_super
vsftpd-7977 [003] .... 577.171495: _cond_resched <-down_write
vsftpd-7977 [003] .... 577.171495: deactivate_locked_super <-deactivate_super
vsftpd-7977 [003] .... 577.171496: proc_kill_sb <-deactivate_locked_super
vsftpd-7977 [003] .... 577.171496: kill_anon_super <-proc_kill_sb
vsftpd-7977 [003] .... 577.171496: generic_shutdown_super <-kill_anon_super
vsftpd-7977 [003] .... 577.171496: shrink_dcache_for_umount <-generic_shutdown_super
vsftpd-7977 [003] .... 577.171496: down_read_trylock <-shrink_dcache_for_umount
vsftpd-7977 [003] .... 577.171497: shrink_dcache_for_umount_subtree <-shrink_dcache_for_umount
vsftpd-7977 [003] .... 577.171497: dentry_lru_prune <-shrink_dcache_for_umount_subtree
vsftpd-7977 [003] .... 577.171498: __d_shrink <-shrink_dcache_for_umount_subtree
vsftpd-7977 [003] .... 577.171498: iput <-shrink_dcache_for_umount_subtree
vsftpd-7977 [003] .... 577.171498: _raw_spin_lock <-_atomic_dec_and_lock
vsftpd-7977 [003] .... 577.171499: generic_delete_inode <-iput
vsftpd-7977 [003] .... 577.171499: evict <-iput
vsftpd-7977 [003] .... 577.171499: _raw_spin_lock <-evict
vsftpd-7977 [003] .... 577.171500: proc_evict_inode <-evict
vsftpd-7977 [003] .... 577.171500: truncate_inode_pages <-proc_evict_inode
vsftpd-7977 [003] .... 577.171500: truncate_inode_pages_range <-truncate_inode_pages
vsftpd-7977 [003] .... 577.171501: end_writeback <-proc_evict_inode
vsftpd-7977 [003] .... 577.171501: _cond_resched <-end_writeback
vsftpd-7977 [003] .... 577.171501: _raw_spin_lock_irq <-end_writeback
vsftpd-7977 [003] .... 577.171501: _cond_resched <-end_writeback
vsftpd-7977 [003] .... 577.171501: put_pid <-proc_evict_inode
vsftpd-7977 [003] .... 577.171502: put_pid: put_pid: NULL
vsftpd-7977 [003] .... 577.171502: pde_put <-proc_evict_inode
vsftpd-7977 [003] .... 577.171502: __remove_inode_hash <-evict
vsftpd-7977 [003] .... 577.171503: _raw_spin_lock <-__remove_inode_hash
vsftpd-7977 [003] .... 577.171503: _raw_spin_lock <-__remove_inode_hash
vsftpd-7977 [003] .... 577.171503: _raw_spin_lock <-evict
vsftpd-7977 [003] .... 577.171504: wake_up_bit <-evict
vsftpd-7977 [003] .... 577.171504: bit_waitqueue <-wake_up_bit
vsftpd-7977 [003] .... 577.171504: __phys_addr <-bit_waitqueue
vsftpd-7977 [003] .... 577.171504: __wake_up_bit <-wake_up_bit
vsftpd-7977 [003] .... 577.171504: destroy_inode <-evict
vsftpd-7977 [003] .... 577.171505: __destroy_inode <-destroy_inode
vsftpd-7977 [003] .... 577.171505: inode_has_buffers <-__destroy_inode
vsftpd-7977 [003] .... 577.171505: __fsnotify_inode_delete <-__destroy_inode
vsftpd-7977 [003] .... 577.171505: fsnotify_clear_marks_by_inode <-__fsnotify_inode_delete
vsftpd-7977 [003] .... 577.171505: _raw_spin_lock <-fsnotify_clear_marks_by_inode
vsftpd-7977 [003] .... 577.171506: proc_destroy_inode <-destroy_inode
vsftpd-7977 [003] .... 577.171506: call_rcu_sched <-proc_destroy_inode
vsftpd-7977 [003] .... 577.171506: __call_rcu <-call_rcu_sched
vsftpd-7977 [003] .... 577.171506: d_free <-shrink_dcache_for_umount_subtree
vsftpd-7977 [003] .... 577.171507: __d_free <-d_free
vsftpd-7977 [003] .... 577.171507: kmem_cache_free <-__d_free
vsftpd-7977 [003] .... 577.171507: __phys_addr <-kmem_cache_free
vsftpd-7977 [003] .... 577.171507: __slab_free <-kmem_cache_free
vsftpd-7977 [003] .... 577.171507: free_debug_processing <-__slab_free
vsftpd-7977 [003] d... 577.171508: check_slab <-free_debug_processing
vsftpd-7977 [003] d... 577.171508: slab_pad_check.part.42 <-check_slab
vsftpd-7977 [003] d... 577.171508: on_freelist <-free_debug_processing
vsftpd-7977 [003] d... 577.171509: check_object <-free_debug_processing
vsftpd-7977 [003] d... 577.171509: check_bytes_and_report <-check_object
vsftpd-7977 [003] d... 577.171510: check_bytes_and_report <-check_object
vsftpd-7977 [003] d... 577.171510: set_track <-free_debug_processing
vsftpd-7977 [003] d... 577.171510: dump_trace <-save_stack_trace
vsftpd-7977 [003] d... 577.171510: print_context_stack <-dump_trace
vsftpd-7977 [003] d... 577.171514: init_object <-free_debug_processing
vsftpd-7977 [003] .... 577.171515: sync_filesystem <-generic_shutdown_super
vsftpd-7977 [003] .... 577.171515: __sync_filesystem <-sync_filesystem
vsftpd-7977 [003] .... 577.171515: __sync_filesystem <-sync_filesystem
vsftpd-7977 [003] .... 577.171516: fsnotify_unmount_inodes <-generic_shutdown_super
vsftpd-7977 [003] .... 577.171516: _raw_spin_lock <-fsnotify_unmount_inodes
vsftpd-7977 [003] .... 577.171516: evict_inodes <-generic_shutdown_super
vsftpd-7977 [003] .... 577.171516: _raw_spin_lock <-evict_inodes
vsftpd-7977 [003] .... 577.171516: dispose_list <-evict_inodes
vsftpd-7977 [003] .... 577.171517: _raw_spin_lock <-generic_shutdown_super
vsftpd-7977 [003] .... 577.171517: up_write <-generic_shutdown_super
vsftpd-7977 [003] .... 577.171517: free_anon_bdev <-kill_anon_super
vsftpd-7977 [003] .... 577.171517: _raw_spin_lock <-free_anon_bdev
vsftpd-7977 [003] .... 577.171518: proc_kill_sb: put_pid_ns: 0xffff8801dc56f320 count:2->1
vsftpd-7977 [003] .... 577.171518: unregister_shrinker <-deactivate_locked_super
vsftpd-7977 [003] .... 577.171518: down_write <-unregister_shrinker
vsftpd-7977 [003] .... 577.171518: _cond_resched <-down_write
vsftpd-7977 [003] .... 577.171519: up_write <-unregister_shrinker
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: _cond_resched <-mutex_lock
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] .... 577.171520: smp_call_function <-on_each_cpu
vsftpd-7977 [003] .... 577.171521: smp_call_function_many <-smp_call_function
vsftpd-7977 [003] .... 577.171521: _raw_spin_lock_irqsave <-smp_call_function_many
vsftpd-7977 [003] d... 577.171521: _raw_spin_unlock_irqrestore <-smp_call_function_many
vsftpd-7977 [003] .... 577.171522: native_send_call_func_ipi <-smp_call_function_many
vsftpd-7977 [003] .... 577.171522: flat_send_IPI_allbutself <-native_send_call_func_ipi
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] d... 577.171533: __call_rcu <-call_rcu_sched
vsftpd-7977 [003] .... 577.171533: wait_for_completion <-_rcu_barrier.isra.31
vsftpd-7977 [003] .... 577.171533: wait_for_common <-wait_for_completion
vsftpd-7977 [003] .... 577.171533: _cond_resched <-wait_for_common
vsftpd-7977 [003] .... 577.171533: _raw_spin_lock_irq <-wait_for_common
vsftpd-7977 [003] .... 577.171534: schedule_timeout <-wait_for_common
vsftpd-7977 [003] .... 577.171534: schedule <-schedule_timeout
vsftpd-7977 [003] .... 577.171534: __schedule <-schedule



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