From: Jiri Bohac [IPX]: Fix NULL pointer dereference on ipx unload Fixes a null pointer dereference when unloading the ipx module. On initialization of the ipx module, registering certain packet types can fail. When this happens, unloading the module later dereferences NULL pointers. This patch fixes that. Please apply. Signed-off-by: Jiri Bohac Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipx/af_ipx.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) --- linux-2.6.20.1.orig/net/ipx/af_ipx.c +++ linux-2.6.20.1/net/ipx/af_ipx.c @@ -2035,19 +2035,27 @@ static void __exit ipx_proto_finito(void ipxitf_cleanup(); - unregister_snap_client(pSNAP_datalink); - pSNAP_datalink = NULL; - - unregister_8022_client(p8022_datalink); - p8022_datalink = NULL; + if (pSNAP_datalink) { + unregister_snap_client(pSNAP_datalink); + pSNAP_datalink = NULL; + } + + if (p8022_datalink) { + unregister_8022_client(p8022_datalink); + p8022_datalink = NULL; + } dev_remove_pack(&ipx_8023_packet_type); - destroy_8023_client(p8023_datalink); - p8023_datalink = NULL; + if (p8023_datalink) { + destroy_8023_client(p8023_datalink); + p8023_datalink = NULL; + } dev_remove_pack(&ipx_dix_packet_type); - destroy_EII_client(pEII_datalink); - pEII_datalink = NULL; + if (pEII_datalink) { + destroy_EII_client(pEII_datalink); + pEII_datalink = NULL; + } proto_unregister(&ipx_proto); sock_unregister(ipx_family_ops.family); --