• David Howells's avatar
    KEYS: Fix an RCU warning · bfeb0360
    David Howells authored
    
    
    Fix the following RCU warning:
    
    ===================================================
    [ INFO: suspicious rcu_dereference_check() usage. ]
    ---------------------------------------------------
    security/keys/request_key.c:116 invoked rcu_dereference_check() without protection!
    
    other info that might help us debug this:
    
    rcu_scheduler_active = 1, debug_locks = 0
    1 lock held by keyctl/5372:
     #0:  (key_types_sem){.+.+.+}, at: [<ffffffff811a4e3d>] key_type_lookup+0x1c/0x70
    
    stack backtrace:
    Pid: 5372, comm: keyctl Not tainted 2.6.34-rc3-cachefs #150
    Call Trace:
     [<ffffffff810515f8>] lockdep_rcu_dereference+0xaa/0xb2
     [<ffffffff811a9220>] call_sbin_request_key+0x156/0x2b6
     [<ffffffff811a4c66>] ? __key_instantiate_and_link+0xb1/0xdc
     [<ffffffff811a4cd3>] ? key_instantiate_and_link+0x42/0x5f
     [<ffffffff811a96b8>] ? request_key_auth_new+0x17b/0x1f3
     [<ffffffff811a8e00>] ? request_key_and_link+0x271/0x400
     [<ffffffff810aba6f>] ? kmem_cache_alloc+0xe1/0x118
     [<ffffffff811a8f1a>] request_key_and_link+0x38b/0x400
     [<ffffffff811a7b72>] sys_request_key+0xf7/0x14a
     [<ffffffff81052227>] ? trace_hardirqs_on_caller+0x10c/0x130
     [<ffffffff81393f5c>] ? trace_hardirqs_on_thunk+0x3a/0x3f
     [<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b
    
    This was caused by doing:
    
    	[root@andromeda ~]# keyctl newring fred @s
    	539196288
    	[root@andromeda ~]# keyctl request2 user a a 539196288
    	request_key: Required key not available
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    bfeb0360