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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-05-09 19:37:36 -0400
committerSteven Rostedt <rostedt@goodmis.org>2013-05-09 20:16:27 -0400
commit19dd603e45199d93d61e9853c596d098e04e5d66 (patch)
treef749edd09d9eeb4c4c989936677e8f2bbdd95dc0 /kernel
parent23ea9c4dda129fe1711f9fbda03c7a9c91cf1322 (diff)
downloadlinux-19dd603e45199d93d61e9853c596d098e04e5d66.tar.gz
ftrace: Fix function probe when more than one probe is added
When the first function probe is added and the function tracer is updated the functions are modified to call the probe. But when a second function is added, it updates the function records to have the second function also update, but it fails to update the actual function itself. This prevents the second (or third or forth and so on) probes from having their functions called. # echo vfs_symlink:enable_event:sched:sched_switch > set_ftrace_filter # echo vfs_unlink:enable_event:sched:sched_switch > set_ftrace_filter # cat trace # tracer: nop # # entries-in-buffer/entries-written: 0/0 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | # touch /tmp/a # rm /tmp/a # cat trace # tracer: nop # # entries-in-buffer/entries-written: 0/0 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | # ln -s /tmp/a # cat trace # tracer: nop # # entries-in-buffer/entries-written: 414/414 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] d..3 2847.923031: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=2786 next_prio=120 <...>-3114 [001] d..4 2847.923035: sched_switch: prev_comm=ln prev_pid=3114 prev_prio=120 prev_state=x ==> next_comm=swapper/1 next_pid=0 next_prio=120 bash-2786 [000] d..3 2847.923535: sched_switch: prev_comm=bash prev_pid=2786 prev_prio=120 prev_state=S ==> next_comm=kworker/0:1 next_pid=34 next_prio=120 kworker/0:1-34 [000] d..3 2847.923552: sched_switch: prev_comm=kworker/0:1 prev_pid=34 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120 <idle>-0 [002] d..3 2847.923554: sched_switch: prev_comm=swapper/2 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=sshd next_pid=2783 next_prio=120 sshd-2783 [002] d..3 2847.923660: sched_switch: prev_comm=sshd prev_pid=2783 prev_prio=120 prev_state=S ==> next_comm=swapper/2 next_pid=0 next_prio=120 Still need to update the functions even though the probe itself does not need to be registered again when added a new probe. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index dcca9fa29bf..b549b0f5b97 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2941,8 +2941,12 @@ static void __enable_ftrace_function_probe(void)
int ret;
int i;
- if (ftrace_probe_registered)
+ if (ftrace_probe_registered) {
+ /* still need to update the function call sites */
+ if (ftrace_enabled)
+ ftrace_run_update_code(FTRACE_UPDATE_CALLS);
return;
+ }
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
struct hlist_head *hhd = &ftrace_func_hash[i];