linux-sg2042/fs/proc
Eric W. Biederman 077130c0cf [NET]: Fix race when opening a proc file while a network namespace is exiting.
The problem:  proc_net files remember which network namespace the are
against but do not remember hold a reference count (as that would pin
the network namespace).   So we currently have a small window where
the reference count on a network namespace may be incremented when opening
a /proc file when it has already gone to zero.

To fix this introduce maybe_get_net and get_proc_net.

maybe_get_net increments the network namespace reference count only if it is
greater then zero, ensuring we don't increment a reference count after it
has gone to zero.

get_proc_net handles all of the magic to go from a proc inode to the network
namespace instance and call maybe_get_net on it.

PROC_NET the old accessor is removed so that we don't get confused and use
the wrong helper function.

Then I fix up the callers to use get_proc_net and handle the case case
where get_proc_net returns NULL.  In that case I return -ENXIO because
effectively the network namespace has already gone away so the files
we are trying to access don't exist anymore.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:49:22 -07:00
..
Makefile [NET]: Make /proc/net per network namespace 2007-10-10 16:49:06 -07:00
array.c sched: accounting regression since rc1 2007-08-23 15:18:02 +02:00
base.c Fix leaks on /proc/{*/sched,sched_debug,timer_list,timer_stats} 2007-07-31 15:39:40 -07:00
generic.c procfs directory entry cleanup 2007-07-16 09:05:43 -07:00
inode-alloc.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
inode.c Fix select on /proc files without ->poll 2007-09-11 17:21:20 -07:00
internal.h [NET]: Make /proc/net per network namespace 2007-10-10 16:49:06 -07:00
kcore.c [PATCH] elf: fix kcore note size calculation 2006-12-07 08:39:38 -08:00
kmsg.c [PATCH] Make most file operations structs in fs/ const 2006-03-28 09:16:06 -08:00
mmu.c [PATCH] fix impossible VmallocChunk 2005-05-17 07:59:10 -07:00
nommu.c [PATCH] mark struct file_operations const 6 2007-02-12 09:48:45 -08:00
proc_devtree.c [POWERPC] Make struct property's value a void * 2007-04-13 03:55:18 +10:00
proc_misc.c x86_64: Avoid too many remote cpu references due to /proc/stat 2007-07-21 18:37:09 -07:00
proc_net.c [NET]: Fix race when opening a proc file while a network namespace is exiting. 2007-10-10 16:49:22 -07:00
proc_sysctl.c Remove redundant check from proc_sys_setattr() 2007-05-08 11:15:10 -07:00
proc_tty.c Make /proc/tty/drivers use seq_list_xxx helpers 2007-07-16 09:05:42 -07:00
root.c [NET]: Make /proc/net per network namespace 2007-10-10 16:49:06 -07:00
task_mmu.c proc: maps protection 2007-05-08 11:15:02 -07:00
task_nommu.c proc: maps protection 2007-05-08 11:15:02 -07:00
vmcore.c [PATCH] i386: Allow i386 crash kernels to handle x86_64 dumps 2007-05-02 19:27:09 +02:00