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authorAndrew Vagin <avagin@openvz.org>2013-08-02 21:16:43 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-14 22:59:07 -0700
commit2d7ddf0a8fa2cffded6b8785f16e0c08c66f5007 (patch)
tree8542d2e7c90cf09ef0abf9fe4d2d7b9ed0a9a735
parentb97f921b94b1e70d5de999fd820ccf8504dc6528 (diff)
downloadvexpress-lsk-2d7ddf0a8fa2cffded6b8785f16e0c08c66f5007.tar.gz
tracing: Fix fields of struct trace_iterator that are zeroed by mistake
commit ed5467da0e369e65b247b99eb6403cb79172bcda upstream. tracing_read_pipe zeros all fields bellow "seq". The declaration contains a comment about that, but it doesn't help. The first field is "snapshot", it's true when current open file is snapshot. Looks obvious, that it should not be zeroed. The second field is "started". It was converted from cpumask_t to cpumask_var_t (v2.6.28-4983-g4462344), in other words it was converted from cpumask to pointer on cpumask. Currently the reference on "started" memory is lost after the first read from tracing_read_pipe and a proper object will never be freed. The "started" is never dereferenced for trace_pipe, because trace_pipe can't have the TRACE_FILE_ANNOTATE options. Link: http://lkml.kernel.org/r/1375463803-3085183-1-git-send-email-avagin@openvz.org Signed-off-by: Andrew Vagin <avagin@openvz.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/ftrace_event.h10
-rw-r--r--kernel/trace/trace.c1
2 files changed, 7 insertions, 4 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 4372658c73a..44cdc11b15c 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -78,6 +78,11 @@ struct trace_iterator {
/* trace_seq for __print_flags() and __print_symbolic() etc. */
struct trace_seq tmp_seq;
+ cpumask_var_t started;
+
+ /* it's true when current open file is snapshot */
+ bool snapshot;
+
/* The below is zeroed out in pipe_read */
struct trace_seq seq;
struct trace_entry *ent;
@@ -90,10 +95,7 @@ struct trace_iterator {
loff_t pos;
long idx;
- cpumask_var_t started;
-
- /* it's true when current open file is snapshot */
- bool snapshot;
+ /* All new field here will be zeroed out in pipe_read */
};
enum trace_iter_flags {
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f7bc3ce6eaf..2a250a2aa02 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4121,6 +4121,7 @@ waitagain:
memset(&iter->seq, 0,
sizeof(struct trace_iterator) -
offsetof(struct trace_iterator, seq));
+ cpumask_clear(iter->started);
iter->pos = -1;
trace_event_read_lock();