Commit fb6bab6a authored Jun 27, 2014 by Oleg Nesterov Committed by Steven Rostedt Jun 30, 2014

tracing/uprobes: Fix the usage of uprobe_buffer_enable() in probe_event_enable()

The usage of uprobe_buffer_enable() added by dcad1a20 is very wrong,

1. uprobe_buffer_enable() and uprobe_buffer_disable() are not balanced,
   _enable() should be called only if !enabled.

2. If uprobe_buffer_enable() fails probe_event_enable() should clear
   tp.flags and free event_file_link.

3. If uprobe_register() fails it should do uprobe_buffer_disable().

Link: http://lkml.kernel.org/p/20140627170146.GA18332@redhat.com



Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Fixes: dcad1a20 "tracing/uprobes: Fetch args before reserving a ring buffer"
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

parent f786106e

kernel/trace/trace_uprobe.c

+19 −12

Original line number	Diff line number	Diff line
		@@ -911,26 +911,33 @@ probe_event_enable(struct trace_uprobe tu, struct ftrace_event_file file,
		tu->tp.flags \|= TP_FLAG_PROFILE;
		}

		ret = uprobe_buffer_enable();
		if (ret < 0)
		return ret;

		WARN_ON(!uprobe_filter_is_empty(&tu->filter));

		if (enabled)
		return 0;

		ret = uprobe_buffer_enable();
		if (ret)
		goto err_flags;

		tu->consumer.filter = filter;
		ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
		if (ret) {
		if (ret)
		goto err_buffer;

		return 0;

		err_buffer:
		uprobe_buffer_disable();

		err_flags:
		if (file) {
		list_del(&link->list);
		kfree(link);
		tu->tp.flags &= ~TP_FLAG_TRACE;
		} else
		} else {
		tu->tp.flags &= ~TP_FLAG_PROFILE;
		}

		return ret;
		}