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> |
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.. | ||
Makefile | ||
array.c | ||
base.c | ||
generic.c | ||
inode-alloc.txt | ||
inode.c | ||
internal.h | ||
kcore.c | ||
kmsg.c | ||
mmu.c | ||
nommu.c | ||
proc_devtree.c | ||
proc_misc.c | ||
proc_net.c | ||
proc_sysctl.c | ||
proc_tty.c | ||
root.c | ||
task_mmu.c | ||
task_nommu.c | ||
vmcore.c |