• Steven Rostedt's avatar
    function-graph: Init curr_ret_stack with ret_stack · ea14eb71
    Steven Rostedt authored
    If the graph tracer is active, and a task is forked but the allocating of
    the processes graph stack fails, it can cause crash later on.
    
    This is due to the temporary stack being NULL, but the curr_ret_stack
    variable is copied from the parent. If it is not -1, then in
    ftrace_graph_probe_sched_switch() the following:
    
    	for (index = next->curr_ret_stack; index >= 0; index--)
    		next->ret_stack[index].calltime += timestamp;
    
    Will cause a kernel OOPS.
    
    Found with Li Zefan's ftrace_stress_test.
    
    Cc: stable@kernel.org
    Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
    ea14eb71
ftrace.c 70.2 KB