[68/98] dccp_probe: Fix module load dependencies between dccp and dccp_probe

[Greg KH]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Neil Horman <nhorman@xxxxxxxxxxxxx>

commit 38ff3e6bb987ec583268da8eb22628293095d43b upstream.

This was just recently reported to me.  When built as modules, the
dccp_probe module has a silent dependency on the dccp module.  This
stems from the fact that the module_init routine of dccp_probe
registers a jprobe on the dccp_sendmsg symbol.  Since the symbol is
only referenced as a text string (the .symbol_name field in the jprobe
struct) rather than the address of the symbol itself, depmod never
picks this dependency up, and so if you load the dccp_probe module
without the dccp module loaded, the register_jprobe call fails with an
-EINVAL, and the whole module load fails.

The fix is pretty easy, we can just wrap the register_jprobe call in a
try_then_request_module call, which forces the dependency to get
satisfied prior to the probe registration.

Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
Acked-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: maximilian attems <max@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/dccp/probe.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/dccp/probe.c
+++ b/net/dccp/probe.c
@@ -164,7 +164,8 @@ static __init int dccpprobe_init(void)
 	if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
 		goto err0;
 
-	ret = register_jprobe(&dccp_send_probe);
+	ret = try_then_request_module((register_jprobe(&dccp_send_probe) == 0),
+					"dccp");
 	if (ret)
 		goto err1;
 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/