Re: [RFC][PATCH] Prevent overriding of Symbols in the Kernel, avoiding Undefined behaviour

[Andrew Morton <akpm@osdl.org>]

Ashutosh Naik <ashutosh.naik@gmail.com> wrote:
>
> This patch ensures that an exported symbol  does not already exist in
>  the kernel or in some other module's exported symbol table. This is
>  done by checking the symbol tables for the exported symbol at the time
>  of loading the module. Currently this is done after the relocation of
>  the symbol.

This patch causes weird things to happen on ppc64.

The only module which is loaded is autofs, and I assume this happens when
autofs is (successfully) loaded.  But unloading autofs and reloading autofs
does not cause a repeat.


kjournald starting.  Commit interval 5 seconds
EXT3 FS on sda6, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
tg3: eth0: Link is up at 100 Mbps, full duplex.
tg3: eth0: Flow control is off for TX and off for RX.
sunrpc: exports duplicate symbol rpc_max_payload (owned by autofs)
lockd: Unknown symbol svc_recv
lockd: Unknown symbol svc_create
lockd: Unknown symbol rpciod_up
lockd: Unknown symbol rpc_destroy_client
lockd: Unknown symbol xdr_encode_netobj
lockd: Unknown symbol svc_destroy
lockd: Unknown symbol xprt_create_proto
lockd: Unknown symbol rpc_delay
lockd: Unknown symbol rpc_call_async
lockd: Unknown symbol rpc_create_client
lockd: Unknown symbol svc_makesock
lockd: Unknown symbol nlm_debug
lockd: Unknown symbol xdr_decode_netobj
lockd: Unknown symbol svc_wake_up
lockd: Unknown symbol rpciod_down
lockd: Unknown symbol svc_exit_thread
lockd: Unknown symbol xdr_encode_string
lockd: Unknown symbol rpc_call_sync
lockd: Unknown symbol xdr_decode_string_inplace
lockd: Unknown symbol svc_set_client
lockd: Unknown symbol svc_process
lockd: Unknown symbol xprt_set_timeout
lockd: Unknown symbol rpc_restart_call
lockd: Unknown symbol svc_create_thread
exportfs: exports duplicate symbol find_exported_dentry (owned by autofs)
sunrpc: exports duplicate symbol rpc_max_payload (owned by autofs)
lockd: Unknown symbol svc_recv
lockd: Unknown symbol svc_create
lockd: Unknown symbol rpciod_up
lockd: Unknown symbol rpc_destroy_client
lockd: Unknown symbol xdr_encode_netobj
lockd: Unknown symbol svc_destroy
lockd: Unknown symbol xprt_create_proto
lockd: Unknown symbol rpc_delay
lockd: Unknown symbol rpc_call_async
lockd: Unknown symbol rpc_create_client
lockd: Unknown symbol svc_makesock
lockd: Unknown symbol nlm_debug
lockd: Unknown symbol xdr_decode_netobj
lockd: Unknown symbol svc_wake_up
lockd: Unknown symbol rpciod_down
lockd: Unknown symbol svc_exit_thread
lockd: Unknown symbol xdr_encode_string
lockd: Unknown symbol rpc_call_sync
lockd: Unknown symbol xdr_decode_string_inplace
lockd: Unknown symbol svc_set_client
lockd: Unknown symbol svc_process
lockd: Unknown symbol xprt_set_timeout
lockd: Unknown symbol rpc_restart_call
lockd: Unknown symbol svc_create_thread
exportfs: exports duplicate symbol find_exported_dentry (owned by autofs)
nfsd: Unknown symbol cache_flush
nfsd: Unknown symbol find_exported_dentry
nfsd: Unknown symbol rpcauth_lookup_credcache
nfsd: Unknown symbol svc_proc_register
nfsd: Unknown symbol cache_register
nfsd: Unknown symbol svc_recv
nfsd: Unknown symbol svc_create
nfsd: Unknown symbol svcauth_unix_purge
nfsd: Unknown symbol rpciod_up
nfsd: Unknown symbol xdr_encode_opaque
nfsd: Unknown symbol xdr_reserve_space
nfsd: Unknown symbol svc_destroy
nfsd: Unknown symbol cache_fresh
nfsd: Unknown symbol auth_domain_put
nfsd: Unknown symbol xdr_inline_decode
nfsd: Unknown symbol xprt_create_proto
nfsd: Unknown symbol nfsd_debug
nfsd: Unknown symbol rpc_call_async
nfsd: Unknown symbol svc_makesock
nfsd: Unknown symbol auth_unix_lookup
nfsd: Unknown symbol svc_seq_show
nfsd: Unknown symbol unix_domain_find
nfsd: Unknown symbol auth_unix_forget_old
nfsd: Unknown symbol svc_proc_unregister
nfsd: Unknown symbol auth_unix_add_addr
nfsd: Unknown symbol cache_init
nfsd: Unknown symbol qword_get
nfsd: Unknown symbol rpc_shutdown_client
nfsd: Unknown symbol rpciod_down
nfsd: Unknown symbol put_rpccred
nfsd: Unknown symbol svc_exit_thread
nfsd: Unknown symbol svc_set_client
nfsd: Unknown symbol lockd_down
nfsd: Unknown symbol xdr_init_decode
nfsd: Unknown symbol cache_unregister
nfsd: Unknown symbol qword_add
nfsd: Unknown symbol lockd_up
nfsd: Unknown symbol nlmsvc_ops
nfsd: Unknown symbol xdr_init_encode
nfsd: Unknown symbol rpc_call_sync
nfsd: Unknown symbol export_op_default
nfsd: Unknown symbol xdr_decode_string_inplace
nfsd: Unknown symbol rpc_new_client
nfsd: Unknown symbol svc_process
nfsd: Unknown symbol svc_reserve
nfsd: Unknown symbol cache_purge
nfsd: Unknown symbol cache_check
nfsd: Unknown symbol qword_addhex
nfsd: Unknown symbol svc_create_thread
nfsd: Unknown symbol auth_domain_find
sunrpc: exports duplicate symbol rpc_max_payload (owned by autofs)
eth0: no IPv6 routers present