diff options
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 53 |
1 files changed, 40 insertions, 13 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 636d45fe69b..9f46e98ba8f 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -35,7 +35,7 @@ struct trace_probe { const char *symbol; /* symbol name */ struct ftrace_event_class class; struct ftrace_event_call call; - struct ftrace_event_file **files; + struct ftrace_event_file * __rcu *files; ssize_t size; /* trace entry size */ unsigned int nr_args; struct probe_arg args[]; @@ -185,9 +185,14 @@ static struct trace_probe *find_trace_probe(const char *event, static int trace_probe_nr_files(struct trace_probe *tp) { - struct ftrace_event_file **file = tp->files; + struct ftrace_event_file **file; int ret = 0; + /* + * Since all tp->files updater is protected by probe_enable_lock, + * we don't need to lock an rcu_read_lock. + */ + file = rcu_dereference_raw(tp->files); if (file) while (*(file++)) ret++; @@ -209,9 +214,10 @@ enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) mutex_lock(&probe_enable_lock); if (file) { - struct ftrace_event_file **new, **old = tp->files; + struct ftrace_event_file **new, **old; int n = trace_probe_nr_files(tp); + old = rcu_dereference_raw(tp->files); /* 1 is for new one and 1 is for stopper */ new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *), GFP_KERNEL); @@ -251,11 +257,17 @@ enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) static int trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file) { + struct ftrace_event_file **files; int i; - if (tp->files) { - for (i = 0; tp->files[i]; i++) - if (tp->files[i] == file) + /* + * Since all tp->files updater is protected by probe_enable_lock, + * we don't need to lock an rcu_read_lock. + */ + files = rcu_dereference_raw(tp->files); + if (files) { + for (i = 0; files[i]; i++) + if (files[i] == file) return i; } @@ -274,10 +286,11 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) mutex_lock(&probe_enable_lock); if (file) { - struct ftrace_event_file **new, **old = tp->files; + struct ftrace_event_file **new, **old; int n = trace_probe_nr_files(tp); int i, j; + old = rcu_dereference_raw(tp->files); if (n == 0 || trace_probe_file_index(tp, file) < 0) { ret = -EINVAL; goto out_unlock; @@ -872,9 +885,16 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs, static __kprobes void kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs) { - struct ftrace_event_file **file = tp->files; + /* + * Note: preempt is already disabled around the kprobe handler. + * However, we still need an smp_read_barrier_depends() corresponding + * to smp_wmb() in rcu_assign_pointer() to access the pointer. + */ + struct ftrace_event_file **file = rcu_dereference_raw(tp->files); + + if (unlikely(!file)) + return; - /* Note: preempt is already disabled around the kprobe handler */ while (*file) { __kprobe_trace_func(tp, regs, *file); file++; @@ -925,9 +945,16 @@ static __kprobes void kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri, struct pt_regs *regs) { - struct ftrace_event_file **file = tp->files; + /* + * Note: preempt is already disabled around the kprobe handler. + * However, we still need an smp_read_barrier_depends() corresponding + * to smp_wmb() in rcu_assign_pointer() to access the pointer. + */ + struct ftrace_event_file **file = rcu_dereference_raw(tp->files); + + if (unlikely(!file)) + return; - /* Note: preempt is already disabled around the kprobe handler */ while (*file) { __kretprobe_trace_func(tp, ri, regs, *file); file++; @@ -935,7 +962,7 @@ kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri, } /* Event entry printers */ -enum print_line_t +static enum print_line_t print_kprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) { @@ -971,7 +998,7 @@ partial: return TRACE_TYPE_PARTIAL_LINE; } -enum print_line_t +static enum print_line_t print_kretprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) { |