tracing/kprobes: Support ftrace_event_file base multibuffer
Support multi-buffer on kprobe-based dynamic events by using ftrace_event_file. Link: http://lkml.kernel.org/r/20130509054449.30398.88343.stgit@mhiramat-M0-7522 Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <tom.zanussi@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu
Steven Rostedt
Родитель
2b106aabe6
Коммит
41a7dd420c
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@ -27,7 +27,6 @@
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/**
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* Kprobe event core functions
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*/
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struct trace_probe {
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struct list_head list;
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struct kretprobe rp; /* Use rp.kp for kprobe use */
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@ -36,6 +35,7 @@ struct trace_probe {
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const char *symbol; /* symbol name */
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struct ftrace_event_class class;
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struct ftrace_event_call call;
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struct ftrace_event_file **files;
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ssize_t size; /* trace entry size */
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unsigned int nr_args;
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struct probe_arg args[];
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@ -183,12 +183,57 @@ static struct trace_probe *find_trace_probe(const char *event,
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return NULL;
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}
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/* Enable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
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static int enable_trace_probe(struct trace_probe *tp, int flag)
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static int trace_probe_nr_files(struct trace_probe *tp)
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{
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struct ftrace_event_file **file = tp->files;
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int ret = 0;
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if (file)
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while (*(file++))
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ret++;
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return ret;
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}
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static DEFINE_MUTEX(probe_enable_lock);
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/*
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* Enable trace_probe
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* if the file is NULL, enable "perf" handler, or enable "trace" handler.
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*/
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static int
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enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
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{
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int ret = 0;
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tp->flags |= flag;
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mutex_lock(&probe_enable_lock);
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if (file) {
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struct ftrace_event_file **new, **old = tp->files;
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int n = trace_probe_nr_files(tp);
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/* 1 is for new one and 1 is for stopper */
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new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *),
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GFP_KERNEL);
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if (!new) {
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ret = -ENOMEM;
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goto out_unlock;
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}
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memcpy(new, old, n * sizeof(struct ftrace_event_file *));
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new[n] = file;
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/* The last one keeps a NULL */
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rcu_assign_pointer(tp->files, new);
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tp->flags |= TP_FLAG_TRACE;
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if (old) {
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/* Make sure the probe is done with old files */
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synchronize_sched();
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kfree(old);
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}
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} else
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tp->flags |= TP_FLAG_PROFILE;
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if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) &&
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!trace_probe_has_gone(tp)) {
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if (trace_probe_is_return(tp))
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@ -197,19 +242,83 @@ static int enable_trace_probe(struct trace_probe *tp, int flag)
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ret = enable_kprobe(&tp->rp.kp);
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}
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out_unlock:
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mutex_unlock(&probe_enable_lock);
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return ret;
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}
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/* Disable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
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static void disable_trace_probe(struct trace_probe *tp, int flag)
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static int
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trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file)
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{
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tp->flags &= ~flag;
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int i;
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if (tp->files) {
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for (i = 0; tp->files[i]; i++)
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if (tp->files[i] == file)
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return i;
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}
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return -1;
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}
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/*
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* Disable trace_probe
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* if the file is NULL, disable "perf" handler, or disable "trace" handler.
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*/
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static int
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disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
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{
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int ret = 0;
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mutex_lock(&probe_enable_lock);
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if (file) {
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struct ftrace_event_file **new, **old = tp->files;
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int n = trace_probe_nr_files(tp);
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int i, j;
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if (n == 0 || trace_probe_file_index(tp, file) < 0) {
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ret = -EINVAL;
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goto out_unlock;
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}
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if (n == 1) { /* Remove the last file */
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tp->flags &= ~TP_FLAG_TRACE;
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new = NULL;
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} else {
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new = kzalloc(n * sizeof(struct ftrace_event_file *),
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GFP_KERNEL);
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if (!new) {
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ret = -ENOMEM;
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goto out_unlock;
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}
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/* This copy & check loop copies the NULL stopper too */
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for (i = 0, j = 0; j < n && i < n + 1; i++)
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if (old[i] != file)
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new[j++] = old[i];
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}
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rcu_assign_pointer(tp->files, new);
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/* Make sure the probe is done with old files */
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synchronize_sched();
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kfree(old);
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} else
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tp->flags &= ~TP_FLAG_PROFILE;
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if (!trace_probe_is_enabled(tp) && trace_probe_is_registered(tp)) {
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if (trace_probe_is_return(tp))
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disable_kretprobe(&tp->rp);
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else
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disable_kprobe(&tp->rp.kp);
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}
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out_unlock:
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mutex_unlock(&probe_enable_lock);
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return ret;
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}
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/* Internal register function - just handle k*probes and flags */
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@ -724,7 +833,8 @@ static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
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/* Kprobe handler */
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static __kprobes void
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kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
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__kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
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struct ftrace_event_file *ftrace_file)
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{
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struct kprobe_trace_entry_head *entry;
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struct ring_buffer_event *event;
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@ -733,14 +843,17 @@ kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
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unsigned long irq_flags;
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struct ftrace_event_call *call = &tp->call;
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WARN_ON(call != ftrace_file->event_call);
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local_save_flags(irq_flags);
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pc = preempt_count();
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dsize = __get_data_size(tp, regs);
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size = sizeof(*entry) + tp->size + dsize;
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event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
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size, irq_flags, pc);
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event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
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call->event.type,
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size, irq_flags, pc);
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if (!event)
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return;
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@ -753,10 +866,23 @@ kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
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irq_flags, pc, regs);
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}
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static __kprobes void
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kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
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{
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struct ftrace_event_file **file = tp->files;
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/* Note: preempt is already disabled around the kprobe handler */
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while (*file) {
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__kprobe_trace_func(tp, regs, *file);
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file++;
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}
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}
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/* Kretprobe handler */
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static __kprobes void
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kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
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struct pt_regs *regs)
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__kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
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struct pt_regs *regs,
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struct ftrace_event_file *ftrace_file)
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{
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struct kretprobe_trace_entry_head *entry;
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struct ring_buffer_event *event;
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@ -765,14 +891,17 @@ kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
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unsigned long irq_flags;
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struct ftrace_event_call *call = &tp->call;
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WARN_ON(call != ftrace_file->event_call);
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local_save_flags(irq_flags);
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pc = preempt_count();
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dsize = __get_data_size(tp, regs);
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size = sizeof(*entry) + tp->size + dsize;
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event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
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size, irq_flags, pc);
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event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
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call->event.type,
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size, irq_flags, pc);
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if (!event)
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return;
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@ -786,6 +915,19 @@ kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
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irq_flags, pc, regs);
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}
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static __kprobes void
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kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
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struct pt_regs *regs)
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{
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struct ftrace_event_file **file = tp->files;
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/* Note: preempt is already disabled around the kprobe handler */
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while (*file) {
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__kretprobe_trace_func(tp, ri, regs, *file);
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file++;
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}
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}
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/* Event entry printers */
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enum print_line_t
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print_kprobe_event(struct trace_iterator *iter, int flags,
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@ -1041,20 +1183,19 @@ int kprobe_register(struct ftrace_event_call *event,
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enum trace_reg type, void *data)
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{
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struct trace_probe *tp = (struct trace_probe *)event->data;
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struct ftrace_event_file *file = data;
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switch (type) {
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case TRACE_REG_REGISTER:
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return enable_trace_probe(tp, TP_FLAG_TRACE);
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return enable_trace_probe(tp, file);
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case TRACE_REG_UNREGISTER:
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disable_trace_probe(tp, TP_FLAG_TRACE);
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return 0;
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return disable_trace_probe(tp, file);
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#ifdef CONFIG_PERF_EVENTS
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case TRACE_REG_PERF_REGISTER:
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return enable_trace_probe(tp, TP_FLAG_PROFILE);
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return enable_trace_probe(tp, NULL);
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case TRACE_REG_PERF_UNREGISTER:
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disable_trace_probe(tp, TP_FLAG_PROFILE);
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return 0;
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return disable_trace_probe(tp, NULL);
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case TRACE_REG_PERF_OPEN:
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case TRACE_REG_PERF_CLOSE:
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case TRACE_REG_PERF_ADD:
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@ -1190,11 +1331,24 @@ static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
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return a1 + a2 + a3 + a4 + a5 + a6;
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}
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static struct ftrace_event_file *
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find_trace_probe_file(struct trace_probe *tp, struct trace_array *tr)
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{
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struct ftrace_event_file *file;
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list_for_each_entry(file, &tr->events, list)
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if (file->event_call == &tp->call)
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return file;
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return NULL;
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}
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static __init int kprobe_trace_self_tests_init(void)
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{
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int ret, warn = 0;
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int (*target)(int, int, int, int, int, int);
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struct trace_probe *tp;
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struct ftrace_event_file *file;
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target = kprobe_trace_selftest_target;
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@ -1204,31 +1358,43 @@ static __init int kprobe_trace_self_tests_init(void)
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"$stack $stack0 +0($stack)",
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create_trace_probe);
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if (WARN_ON_ONCE(ret)) {
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pr_warning("error on probing function entry.\n");
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pr_warn("error on probing function entry.\n");
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warn++;
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} else {
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/* Enable trace point */
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tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
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if (WARN_ON_ONCE(tp == NULL)) {
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pr_warning("error on getting new probe.\n");
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pr_warn("error on getting new probe.\n");
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warn++;
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} else
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enable_trace_probe(tp, TP_FLAG_TRACE);
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} else {
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file = find_trace_probe_file(tp, top_trace_array());
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if (WARN_ON_ONCE(file == NULL)) {
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pr_warn("error on getting probe file.\n");
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warn++;
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} else
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enable_trace_probe(tp, file);
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}
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}
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ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
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"$retval", create_trace_probe);
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if (WARN_ON_ONCE(ret)) {
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pr_warning("error on probing function return.\n");
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pr_warn("error on probing function return.\n");
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warn++;
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} else {
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/* Enable trace point */
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tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
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if (WARN_ON_ONCE(tp == NULL)) {
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pr_warning("error on getting new probe.\n");
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pr_warn("error on getting 2nd new probe.\n");
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warn++;
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} else
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enable_trace_probe(tp, TP_FLAG_TRACE);
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} else {
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file = find_trace_probe_file(tp, top_trace_array());
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if (WARN_ON_ONCE(file == NULL)) {
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pr_warn("error on getting probe file.\n");
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warn++;
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} else
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enable_trace_probe(tp, file);
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}
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}
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if (warn)
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@ -1239,27 +1405,39 @@ static __init int kprobe_trace_self_tests_init(void)
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/* Disable trace points before removing it */
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tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
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if (WARN_ON_ONCE(tp == NULL)) {
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pr_warning("error on getting test probe.\n");
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pr_warn("error on getting test probe.\n");
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warn++;
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} else
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disable_trace_probe(tp, TP_FLAG_TRACE);
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} else {
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file = find_trace_probe_file(tp, top_trace_array());
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if (WARN_ON_ONCE(file == NULL)) {
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pr_warn("error on getting probe file.\n");
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warn++;
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} else
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disable_trace_probe(tp, file);
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}
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tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
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if (WARN_ON_ONCE(tp == NULL)) {
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pr_warning("error on getting 2nd test probe.\n");
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pr_warn("error on getting 2nd test probe.\n");
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warn++;
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} else
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disable_trace_probe(tp, TP_FLAG_TRACE);
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} else {
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file = find_trace_probe_file(tp, top_trace_array());
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if (WARN_ON_ONCE(file == NULL)) {
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pr_warn("error on getting probe file.\n");
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warn++;
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} else
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disable_trace_probe(tp, file);
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}
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ret = traceprobe_command("-:testprobe", create_trace_probe);
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if (WARN_ON_ONCE(ret)) {
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pr_warning("error on deleting a probe.\n");
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pr_warn("error on deleting a probe.\n");
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warn++;
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}
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ret = traceprobe_command("-:testprobe2", create_trace_probe);
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if (WARN_ON_ONCE(ret)) {
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pr_warning("error on deleting a probe.\n");
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pr_warn("error on deleting a probe.\n");
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warn++;
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}
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