(2013/07/04 12:33), Steven Rostedt wrote: > From: Oleg Nesterov <[email protected]> > > Change trace_remove_event_call(call) to return the error if this > call is active. This is what the callers assume but can't verify > outside of the tracing locks. Both trace_kprobe.c/trace_uprobe.c > need the additional changes, unregister_trace_probe() should abort > if trace_remove_event_call() fails. > > We also check TRACE_EVENT_FL_REF_MASK to ensure that nobody opened > the files we are going to remove, these means that nobody can access > the soon-to-be-freed ftrace_event_file/call via filp->private_data. > > Link: http://lkml.kernel.org/r/[email protected]
This looks good for me ;) Reviewed-by: Masami Hiramatsu <[email protected]> Thanks! > > Signed-off-by: Oleg Nesterov <[email protected]> > Signed-off-by: Steven Rostedt <[email protected]> > --- > include/linux/ftrace_event.h | 2 +- > kernel/trace/trace_events.c | 33 +++++++++++++++++++++++++++++++-- > 2 files changed, 32 insertions(+), 3 deletions(-) > > diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h > index 72ff2c6..bdf6bdd 100644 > --- a/include/linux/ftrace_event.h > +++ b/include/linux/ftrace_event.h > @@ -338,7 +338,7 @@ extern int trace_define_field(struct ftrace_event_call > *call, const char *type, > const char *name, int offset, int size, > int is_signed, int filter_type); > extern int trace_add_event_call(struct ftrace_event_call *call); > -extern void trace_remove_event_call(struct ftrace_event_call *call); > +extern int trace_remove_event_call(struct ftrace_event_call *call); > > #define is_signed_type(type) (((type)(-1)) < (type)1) > > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 90cf243..1a5547e 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -1766,16 +1766,45 @@ static void __trace_remove_event_call(struct > ftrace_event_call *call) > destroy_preds(call); > } > > +static int probe_remove_event_call(struct ftrace_event_call *call) > +{ > + struct trace_array *tr; > + struct ftrace_event_file *file; > + > + if (call->flags & TRACE_EVENT_FL_REF_MASK) > + return -EBUSY; > + > +#ifdef CONFIG_PERF_EVENTS > + if (call->perf_refcount) > + return -EBUSY; > +#endif > + do_for_each_event_file(tr, file) { > + if (file->event_call != call) > + continue; > + if (file->flags & FTRACE_EVENT_FL_ENABLED) > + return -EBUSY; > + break; > + } while_for_each_event_file(); > + > + __trace_remove_event_call(call); > + > + return 0; > +} > + > /* Remove an event_call */ > -void trace_remove_event_call(struct ftrace_event_call *call) > +int trace_remove_event_call(struct ftrace_event_call *call) > { > + int ret; > + > mutex_lock(&trace_types_lock); > mutex_lock(&event_mutex); > down_write(&trace_event_sem); > - __trace_remove_event_call(call); > + ret = probe_remove_event_call(call); > up_write(&trace_event_sem); > mutex_unlock(&event_mutex); > mutex_unlock(&trace_types_lock); > + > + return ret; > } > > #define for_each_event(event, start, end) \ > -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
