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 and Steffen. Signed-off-by: Gao feng <[email protected]> --- include/linux/netlink.h | 6 +++++- net/netlink/af_netlink.c | 25 +++++++++++++++++++++---- 2 files changed, 26 insertions(+), 5 deletions(-) diff --git a/include/linux/netlink.h b/include/linux/netlink.h index f74dd13..381f7d6 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -232,6 +232,8 @@ 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; @@ -249,11 +251,13 @@ __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags) 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_done(struct netlink_callback *cb); extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, const struct nlmsghdr *nlh, struct netlink_dump_control *control); diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 5270238..3190dae 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1769,6 +1769,13 @@ errout_skb: return err; } +int netlink_dump_done(struct netlink_callback *cb) +{ + module_put(cb->module); + return 0; +} +EXPORT_SYMBOL(netlink_dump_done); + int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, const struct nlmsghdr *nlh, struct netlink_dump_control *control) @@ -1786,6 +1793,7 @@ 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; @@ -1796,19 +1804,28 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
