jump label: Fix module __init section race
Jump label uses is_module_text_address() to ensure that the module __init sections are valid before updating them. However, between the check for a valid module __init section and the subsequent jump label update, the module's __init section could be freed out from under us. We fix this potential race by adding a notifier callback to the MODULE_STATE_LIVE state. This notifier is called *after* the __init section has been run but before it is going to be freed. In the callback, the jump label code zeros the key value for any __init jump code within the module, and we add a check for a non-zero key value when we update jump labels. In this way we require no additional data structures. Thanks to Mathieu Desnoyers for pointing out this race condition. Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <c6f037b7598777668025ceedd9294212fd95fa34.1285965957.git.jbaron@redhat.com> [ Renamed remove_module_init() to remove_jump_label_module_init() as suggested by Masami Hiramatsu. ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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