linux/fs/proc
Sukadev Bhattiprolu 29f12ca321 pidns: fix a leak in /proc dentries and inodes with pid namespaces.
Daniel Lezcano reported a leak in 'struct pid' and 'struct pid_namespace'
that is discussed in:

	http://lkml.org/lkml/2009/10/2/159.

To summarize the thread, when container-init is terminated, it sets the
PF_EXITING flag, zaps other processes in the container and waits to reap
them.  As a part of reaping, the container-init should flush any /proc
dentries associated with the processes.  But because the container-init is
itself exiting and the following PF_EXITING check, the dentries are not
flushed, resulting in leak in /proc inodes and dentries.

This fix reverts the commit 7766755a2f ("Fix /proc dcache deadlock
in do_exit") which introduced the check for PF_EXITING.  At the time of
the commit, shrink_dcache_parent() flushed dentries from other filesystems
also and could have caused a deadlock which the commit fixed.  But as
pointed out by Eric Biederman, after commit 0feae5c47a,
shrink_dcache_parent() no longer affects other filesystems.  So reverting
the commit is now safe.

As pointed out by Jan Kara, the leak is not as critical since the
unclaimed space will be reclaimed under memory pressure or by:

	echo 3 > /proc/sys/vm/drop_caches

But since this check is no longer required, its best to remove it.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Reported-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Jan Kara <jack@ucw.cz>
Cc: Andrea Arcangeli <andrea@cpushare.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-12 07:25:57 -08:00
..
Kconfig proc: move PROC_PAGE_MONITOR to fs/proc/Kconfig 2008-10-10 04:18:57 +04:00
Makefile proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
array.c procfs: disable per-task stack usage on NOMMU 2009-09-24 17:11:24 -07:00
base.c pidns: fix a leak in /proc dentries and inodes with pid namespaces. 2009-11-12 07:25:57 -08:00
cmdline.c proc: switch /proc/cmdline to seq_file 2008-10-23 14:29:04 +04:00
cpuinfo.c proc: move /proc/cpuinfo code to fs/proc/cpuinfo.c 2008-10-23 15:05:11 +04:00
devices.c proc: move /proc/devices code to fs/proc/devices.c 2008-10-23 15:02:18 +04:00
generic.c proc 1/2: do PDE usecounting even for ->read_proc, ->write_proc 2009-03-31 01:14:27 +04:00
inode.c proc 2/2: remove struct proc_dir_entry::owner 2009-03-31 01:14:44 +04:00
internal.h Move junk from proc_fs.h to fs/proc/internal.h 2009-06-11 21:36:01 -04:00
interrupts.c proc: move /proc/interrupts boilerplate code to fs/proc/interrupts.c 2008-10-23 15:15:46 +04:00
kcore.c fs: includecheck fix: proc, kcore.c 2009-10-08 07:36:38 -07:00
kmsg.c proc: move /proc/kmsg creation to fs/proc/kmsg.c 2008-10-23 14:35:08 +04:00
loadavg.c sched, timers: cleanup avenrun users 2009-05-15 15:32:45 +02:00
meminfo.c hwpoison: fix/proc/meminfo alignment 2009-10-29 07:39:25 -07:00
mmu.c fs/proc/mmu.c: headers butchery 2007-10-17 08:42:48 -07:00
nommu.c seq_file: constify seq_operations 2009-09-23 07:39:29 -07:00
page.c pagemap: export KPF_HWPOISON 2009-10-08 07:36:39 -07:00
proc_devtree.c procfs: remove sparse errors in proc_devtree.c 2009-06-18 13:03:41 -07:00
proc_net.c proc: stop using BKL 2009-01-05 12:27:44 +03:00
proc_sysctl.c sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
proc_tty.c proc tty: remove struct tty_operations::read_proc 2009-04-01 08:59:10 -07:00
root.c Convert obvious places to deactivate_locked_super() 2009-05-09 10:49:40 -04:00
softirqs.c proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
stat.c proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
task_mmu.c procfs: provide stack information for threads 2009-09-23 07:39:41 -07:00
task_nommu.c mm_for_maps: shift down_read(mmap_sem) to the caller 2009-08-10 20:48:32 +10:00
uptime.c [PATCH] Fix idle time field in /proc/uptime 2009-09-24 10:16:24 +02:00
version.c proc: switch /proc/version to seq_file 2008-10-23 14:19:58 +04:00
vmcore.c proc: vmcore - use kzalloc in get_new_element() 2009-06-18 13:03:41 -07:00