[PATCH] inet_diag: fix panic when unload inet_diag
From: Gao feng <hidden>
Date: 2012-09-25 03:00:13
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
when inet_diag being compiled as module, inet_diag_handler_dump set netlink_dump_control.dump to inet_diag_dump,so if module inet_diag is unloaded,netlink will still try to call this function in netlink_dump. this will cause kernel panic. fix this by adding a reference of inet_diag module before setting netlink_callback, and release this reference in netlink_callback.done. Thanks for all help from Stephen,Jan and Eric. Signed-off-by: Gao feng <redacted> --- net/ipv4/inet_diag.c | 46 ++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 570e61f..e573090 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c@@ -903,6 +903,12 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) return __inet_diag_dump(skb, cb, nlmsg_data(cb->nlh), bc); } +static int inet_diag_done(struct netlink_callback *cb) +{ + module_put(THIS_MODULE); + return 0; +} + static inline int inet_diag_type2proto(int type) { switch (type) {
@@ -972,8 +978,26 @@ static int inet_diag_rcv_msg_compat(struct sk_buff *skb, struct nlmsghdr *nlh) { struct netlink_dump_control c = { .dump = inet_diag_dump_compat, + .done = inet_diag_done, }; - return netlink_dump_start(net->diag_nlsk, skb, nlh, &c); + int err; + /* + * netlink_dump will call inet_diag_dump_compat, + * so we need a reference of THIS_MODULE. + */ + if (!try_module_get(THIS_MODULE)) + return -EPROTONOSUPPORT; + + err = netlink_dump_start(net->diag_nlsk, skb, nlh, &c); + + if ((err != -EINTR) && (err != -ENOBUFS)) { + /* + * netlink_callback set failed, release the + * referenct of THIS_MODULE. + */ + module_put(THIS_MODULE); + } + return err; } }
@@ -1001,8 +1025,26 @@ static int inet_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h) { struct netlink_dump_control c = { .dump = inet_diag_dump, + .done = inet_diag_done, }; - return netlink_dump_start(net->diag_nlsk, skb, h, &c); + int err; + /* + * netlink_dump will call inet_diag_dump, + * so we need a reference of THIS_MODULE. + */ + if (!try_module_get(THIS_MODULE)) + return -EPROTONOSUPPORT; + + err = netlink_dump_start(net->diag_nlsk, skb, h, &c); + + if ((err != -EINTR) && (err != -ENOBUFS)) { + /* + * netlink_callback set failed, release the + * referenct of THIS_MODULE. + */ + module_put(THIS_MODULE); + } + return err; } }
--
1.7.7