diff options
Diffstat (limited to 'kernel/trace/fgraph.c')
| -rw-r--r-- | kernel/trace/fgraph.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 67e0c462b059..1af321dec0f1 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -96,11 +96,34 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, return 0; } +/* + * Not all archs define MCOUNT_INSN_SIZE which is used to look for direct + * functions. But those archs currently don't support direct functions + * anyway, and ftrace_find_rec_direct() is just a stub for them. + * Define MCOUNT_INSN_SIZE to keep those archs compiling. + */ +#ifndef MCOUNT_INSN_SIZE +/* Make sure this only works without direct calls */ +# ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +# error MCOUNT_INSN_SIZE not defined with direct calls enabled +# endif +# define MCOUNT_INSN_SIZE 0 +#endif + int function_graph_enter(unsigned long ret, unsigned long func, unsigned long frame_pointer, unsigned long *retp) { struct ftrace_graph_ent trace; + /* + * Skip graph tracing if the return location is served by direct trampoline, + * since call sequence and return addresses is unpredicatable anymore. + * Ex: BPF trampoline may call original function and may skip frame + * depending on type of BPF programs attached. + */ + if (ftrace_direct_func_count && + ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE)) + return -EBUSY; trace.func = func; trace.depth = ++current->curr_ret_depth; |