[tip:tracing/urgent] tracing/filters: fix NULL pointer dereference

[Li Zefan <lizf@cn.fujitsu.com>]

Commit-ID:  bcabd91c271e50eebc0cb9220ac92700332b452e
Gitweb:     http://git.kernel.org/tip/bcabd91c271e50eebc0cb9220ac92700332b452e
Author:     Li Zefan <lizf@cn.fujitsu.com>
AuthorDate: Sat, 11 Apr 2009 15:52:35 +0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 12 Apr 2009 11:59:28 +0200

tracing/filters: fix NULL pointer dereference

Try this, and you'll see NULL pointer dereference bug:

  # echo -n 'parent_comm ==' > sched/sched_process_fork/filter

Because we passed NULL ptr to simple_strtoull().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49E04C43.1050504@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 kernel/trace/trace_events_filter.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 026be41..9d2162f 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -410,6 +410,11 @@ int filter_parse(char **pbuf, struct filter_pred *pred)
 		}
 	}
 
+	if (!val_str) {
+		pred->field_name = NULL;
+		return -EINVAL;
+	}
+
 	pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);
 	if (!pred->field_name)
 		return -ENOMEM;