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Message-Id: <1349325689-16104-1-git-send-email-gaofeng@cn.fujitsu.com>
Date: Thu, 4 Oct 2012 12:41:19 +0800
From: Gao feng <gaofeng@...fujitsu.com>
To: davem@...emloft.net, eric.dumazet@...il.com,
steffen.klassert@...unet.com
Cc: netfilter-devel@...r.kernel.org, linux-rdma@...r.kernel.org,
netdev@...r.kernel.org, linux-crypto@...r.kernel.org,
pablo@...filter.org, stephen.hemminger@...tta.com, jengelh@...i.de,
Gao feng <gaofeng@...fujitsu.com>
Subject: [patch v3 01/11] netlink: add reference of module in netlink_dump_start
I get a panic when I use ss -a and rmmod inet_diag at the
same time.
it's because netlink_dump use inet_diag_dump witch function
belongs to module inet_diag.
I search the codes and find many modules have the same problem.
We need add reference of the module witch the cb->dump belongs
to.
Thanks for all help from Stephen,Jan,Eric,Steffen and Pablo.
Change From v2:
delete netlink_dump_done,and call module_put in netlink_dump
and netlink_sock_destruct.
Signed-off-by: Gao feng <gaofeng@...fujitsu.com>
---
include/linux/netlink.h | 5 ++++-
net/netlink/af_netlink.c | 21 +++++++++++++++++----
2 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index f80c56a..bf4e501 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -245,6 +245,8 @@ struct netlink_callback {
struct netlink_callback *cb);
int (*done)(struct netlink_callback *cb);
void *data;
+ /* the module that dump function belong to */
+ struct module *module;
u16 family;
u16 min_dump_alloc;
unsigned int prev_seq, seq;
@@ -262,8 +264,9 @@ __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int fla
struct netlink_dump_control {
int (*dump)(struct sk_buff *skb, struct netlink_callback *);
- int (*done)(struct netlink_callback*);
+ int (*done)(struct netlink_callback *);
void *data;
+ struct module *module;
u16 min_dump_alloc;
};
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 0f2e3ad..0905dfb 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -169,6 +169,7 @@ static void netlink_sock_destruct(struct sock *sk)
if (nlk->cb) {
if (nlk->cb->done)
nlk->cb->done(nlk->cb);
+ module_put(nlk->cb->module);
netlink_destroy_callback(nlk->cb);
}
@@ -1755,6 +1756,8 @@ static int netlink_dump(struct sock *sk)
if (cb->done)
cb->done(cb);
+
+ module_put(cb->module);
nlk->cb = NULL;
mutex_unlock(nlk->cb_mutex);
@@ -1784,6 +1787,7 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
cb->done = control->done;
cb->nlh = nlh;
cb->data = control->data;
+ cb->module = control->module;
cb->min_dump_alloc = control->min_dump_alloc;
atomic_inc(&skb->users);
cb->skb = skb;
@@ -1794,19 +1798,28 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
return -ECONNREFUSED;
}
nlk = nlk_sk(sk);
- /* A dump is in progress... */
+
mutex_lock(nlk->cb_mutex);
+ /* A dump is in progress... */
if (nlk->cb) {
mutex_unlock(nlk->cb_mutex);
netlink_destroy_callback(cb);
- sock_put(sk);
- return -EBUSY;
+ ret = -EBUSY;
+ goto out;
}
+ /* add reference of module witch cb->dump belong to */
+ if (!try_module_get(cb->module)) {
+ mutex_unlock(nlk->cb_mutex);
+ netlink_destroy_callback(cb);
+ ret = -EPROTONOSUPPORT;
+ goto out;
+ }
+
nlk->cb = cb;
mutex_unlock(nlk->cb_mutex);
ret = netlink_dump(sk);
-
+out:
sock_put(sk);
if (ret)
--
1.7.7.6
--
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