[patch v3 01/11] netlink: add reference of module in netlink_dump_start
From: Gao feng <hidden>
Date: 2012-10-04 04:41:19
Also in:
linux-rdma, netdev, netfilter-devel
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 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 <redacted> --- 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