Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=284b327be2f86cf751316ff344b6945e580e654f
Commit: 284b327be2f86cf751316ff344b6945e580e654f
Parent: 5c80f1ae9842a8b7985acd0f02efb9828effb05f
Author: Pavel Emelyanov <[EMAIL PROTECTED]>
AuthorDate: Sat Nov 10 22:08:30 2007 -0800
Committer: David S. Miller <[EMAIL PROTECTED]>
CommitDate: Sat Nov 10 22:08:30 2007 -0800
[UNIX]: The unix_nr_socks limit can be exceeded
The unix_nr_socks value is limited with the 2 * get_max_files() value,
as seen from the unix_create1(). However, the check and the actual
increment are separated with the GFP_KERNEL allocation, so this limit
can be exceeded under a memory pressure - task may go to sleep freeing
the pages and some other task will be allowed to allocate a new sock
and so on and so forth.
So make the increment before the check (similar thing is done in the
sock_kmalloc) and go to kmalloc after this.
Signed-off-by: Pavel Emelyanov <[EMAIL PROTECTED]>
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
net/unix/af_unix.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index ab9048a..e835da8 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -599,15 +599,14 @@ static struct sock * unix_create1(struct net *net, struct
socket *sock)
struct sock *sk = NULL;
struct unix_sock *u;
- if (atomic_read(&unix_nr_socks) >= 2*get_max_files())
+ atomic_inc(&unix_nr_socks);
+ if (atomic_read(&unix_nr_socks) > 2 * get_max_files())
goto out;
sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
if (!sk)
goto out;
- atomic_inc(&unix_nr_socks);
-
sock_init_data(sock,sk);
lockdep_set_class(&sk->sk_receive_queue.lock,
&af_unix_sk_receive_queue_lock_key);
@@ -625,6 +624,8 @@ static struct sock * unix_create1(struct net *net, struct
socket *sock)
init_waitqueue_head(&u->peer_wait);
unix_insert_socket(unix_sockets_unbound, sk);
out:
+ if (sk == NULL)
+ atomic_dec(&unix_nr_socks);
return sk;
}
-
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