ftrace: freeze kprobe'd records
PATCH 4/4 ftrace: freeze kprobe'd records
Let records identified as being kprobe'd be marked as "frozen". The trouble with records which have a kprobe installed on their mcount call-site is that they don't get updated. So if such a function which is currently being traced gets its tracing disabled due to a new filter rule (or because it was added to the notrace list) then it won't be updated and continue being traced. This patch allows scanning of all frozen records during tracing to check if they should be traced.
Signed-off-by Abhishek Sagar <[email protected]>
---
include/linux/ftrace.h +5 -1
@@ -49,6 +49,7 @@ enum {FTRACE_FL_ENABLED = (1 <<3 ),FTRACE_FL_NOTRACE = (1 <<4 ),FTRACE_FL_CONVERTED = (1 <<5 ), + FTRACE_FL_FROZEN = (1 << 6), }; struct dyn_ftrace {
@@ -73,15 +74,18 @@ extern void ftrace_caller(void);extern void ftrace_call (void );extern void mcount_call (void ); +extern int skip_trace (unsigned long ip); +void ftrace_disable_daemon (void );void ftrace_enable_daemon (void );#else +# define skip_trace (ip) ({ 0; })# define ftrace_force_update () ({ 0; })# define ftrace_set_filter (buf, len, reset) do { } while (0)# define ftrace_disable_daemon () do { } while (0)# define ftrace_enable_daemon () do { } while (0) -#endif +#endif /* CONFIG_DYNAMIC_FTRACE */ /* totally disable ftrace - can not re-enable after this */ void ftrace_kill (void );
kernel/trace/ftrace.c +79 -2
114 lines not on this page · raw message
kernel/trace/trace.c +3 -0
@@ -988,6 +988,9 @@ function_trace_call(unsigned long ip, unsigned long parent_ip)if (unlikely (!tracer_enabled))return ; +if (skip_trace (ip)) +return ; +local_irq_save (flags); cpu =raw_smp_processor_id (); data = tr->data[cpu];