netlink: add reference of module in netlink_dump_start
[ Upstream commit 6dc878a8ca39e93f70c42f3dd7260bde10c1e0f1 ]
I get a panic when I use ss -a and rmmod inet_diag at the
same time.
It's because netlink_dump uses inet_diag_dump which belongs to module
inet_diag.
I search the codes and find many modules have the same problem. We
need to add a reference to the module which the cb->dump belongs to.
Thanks for all help from Stephen,Jan,Eric,Steffen and Pablo.
Change From v3:
change netlink_dump_start to inline,suggestion from Pablo and
Eric.
Change From v2:
delete netlink_dump_done,and call module_put in netlink_dump
and netlink_sock_destruct.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index a2092f5..b23e9cd 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -153,6 +153,7 @@
#include <linux/capability.h>
#include <linux/skbuff.h>
+#include <linux/export.h>
struct net;
@@ -226,6 +227,8 @@
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;
@@ -251,14 +254,24 @@
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;
};
-extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
- const struct nlmsghdr *nlh,
- struct netlink_dump_control *control);
+extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
+ const struct nlmsghdr *nlh,
+ struct netlink_dump_control *control);
+static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
+ const struct nlmsghdr *nlh,
+ struct netlink_dump_control *control)
+{
+ if (!control->module)
+ control->module = THIS_MODULE;
+
+ return __netlink_dump_start(ssk, skb, nlh, control);
+}
#define NL_NONROOT_RECV 0x1