[patch v4 1/2] netlink: add reference of module in netlink_dump_start
flat view
STALE5121d
From: Gao feng <hidden>
Date: 2012-10-05 06:15:48
Also in:
linux-rdma
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 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 <redacted> --- include/linux/netlink.h | 20 ++++++++++++++++---- net/netlink/af_netlink.c | 29 +++++++++++++++++++++-------- 2 files changed, 37 insertions(+), 12 deletions(-)
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index f80c56a..6d3af05 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;
@@ -262,14 +264,24 @@ __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; }; -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); +} #endif /* __KERNEL__ */
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 0f2e3ad..01e944a 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c@@ -169,6 +169,8 @@ 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); }
@@ -1758,6 +1760,7 @@ static int netlink_dump(struct sock *sk) nlk->cb = NULL; mutex_unlock(nlk->cb_mutex); + module_put(cb->module); netlink_consume_callback(cb); return 0;
@@ -1767,9 +1770,9 @@ errout_skb: return err; } -int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, - const struct nlmsghdr *nlh, - struct netlink_dump_control *control) +int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, + const struct nlmsghdr *nlh, + struct netlink_dump_control *control) { struct netlink_callback *cb; struct sock *sk;
@@ -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 which cb->dump belongs 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)
@@ -1817,7 +1830,7 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, */ return -EINTR; } -EXPORT_SYMBOL(netlink_dump_start); +EXPORT_SYMBOL(__netlink_dump_start); void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) {
--
1.7.7.6
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