From: Josef Bacik josef@toxicpanda.com
[ Upstream commit c58b6b0372de0d4cd0536d6585addd1b36b151ae ]
I was attempting to use pid filtering with function_graph, but it wasn't allowing anything to make it through. Turns out ftrace_trace_task returns false if ftrace_ignore_pid is not-empty, which isn't correct anymore. We're now setting it to FTRACE_PID_IGNORE if we need to ignore that pid, otherwise it's set to the pid (which is weird considering the name) or to FTRACE_PID_TRACE. Fix the check to check for != FTRACE_PID_IGNORE. With this we can now use function_graph with pid filtering.
Link: https://lkml.kernel.org/r/20200725005048.1790-1-josef@toxicpanda.com
Fixes: 717e3f5ebc82 ("ftrace: Make function trace pid filtering a bit more exact") Signed-off-by: Josef Bacik josef@toxicpanda.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/ftrace.c | 3 --- kernel/trace/trace.h | 7 ++++++- 2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1903b80db6ebc..7d879fae3777f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -139,9 +139,6 @@ static inline void ftrace_ops_init(struct ftrace_ops *ops) #endif }
-#define FTRACE_PID_IGNORE -1 -#define FTRACE_PID_TRACE -2 - static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f21607f871891..610d21355526d 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1103,6 +1103,10 @@ print_graph_function_flags(struct trace_iterator *iter, u32 flags) extern struct list_head ftrace_pids;
#ifdef CONFIG_FUNCTION_TRACER + +#define FTRACE_PID_IGNORE -1 +#define FTRACE_PID_TRACE -2 + struct ftrace_func_command { struct list_head list; char *name; @@ -1114,7 +1118,8 @@ struct ftrace_func_command { extern bool ftrace_filter_param __initdata; static inline int ftrace_trace_task(struct trace_array *tr) { - return !this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid); + return this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid) != + FTRACE_PID_IGNORE; } extern int ftrace_is_dead(void); int ftrace_create_function_files(struct trace_array *tr,