Commit 575570f0 authored Jul 27, 2010 by Shaohua Li Committed by Steven Rostedt Aug 06, 2010

tracing: Fix an unallocated memory access in function_graph



With CONFIG_DEBUG_PAGEALLOC, I observed an unallocated memory access in
function_graph trace. It appears we find a small size entry in ring buffer,
but we access it as a big size entry. The access overflows the page size
and touches an unallocated page.

Cc: <stable@kernel.org>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
LKML-Reference: <1280217994.32400.76.camel@sli10-desk.sh.intel.com>
[ Added a comment to explain the problem - SDR ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

parent 8a4fd31e

kernel/trace/trace_functions_graph.c

+9 −1

Original line number	Original line	Diff line number	Diff line
	@@ -507,7 +507,15 @@ get_return_for_leaf(struct trace_iterator *iter,
	* if the output fails.		* if the output fails.
	*/		*/
	data->ent = *curr;		data->ent = *curr;
			/*
			* If the next event is not a return type, then
			* we only care about what type it is. Otherwise we can
			* safely copy the entire event.
			*/
			if (next->ent.type == TRACE_GRAPH_RET)
	data->ret = *next;		data->ret = *next;
			else
			data->ret.ent.type = next->ent.type;
	}		}
	}		}