Re: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list
- From: Steven Rostedt <rostedt@xxxxxxxxxxx>
- Date: Wed, 16 Sep 2009 10:29:31 -0400
On Wed, 2009-09-16 at 10:17 -0400, Masami Hiramatsu wrote:
Steven Rostedt wrote:
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ba34920..38e82a5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1009,10 +1009,14 @@ static int __trace_add_event_call(struct ftrace_event_call *call)
if (!d_events)
return -ENOENT;
+ INIT_LIST_HEAD(&call->list);
The INIT_LIST_HEAD is not needed here. The list_add will assign it.
Without initializing it, list debugging code warns always :-)
Please see, __list_add()@lib/list_debug.c
/me looks
from: include/linux/list.h
static inline void list_add(struct list_head *new, struct list_head *head)
{
__list_add(new, head, head->next);
}
from: lib/list_debug.c
void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next)
{
WARN(next->prev != prev,
"list_add corruption. next->prev should be "
"prev (%p), but was %p. (next=%p).\n",
prev, next->prev, next);
WARN(prev->next != next,
"list_add corruption. prev->next should be "
"next (%p), but was %p. (prev=%p).\n",
next, prev->next, prev);
next->prev = new;
new->next = next;
new->prev = prev;
prev->next = new;
}
What you pass in is:
list_add(&call->list, &ftrace_events);
new = &call->list;
prev = &ftrace_events->prev;
next = &ftrace_events->next;
The above code never tests "new". The INIT_LIST_HEAD is useless.
-- Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
- Follow-Ups:
- [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list take 2
- From: Masami Hiramatsu
- [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list take 2
- References:
- [PATCH tracing/kprobes 0/6] tracing/kprobes: kprobe-based event tracer update and perf support
- From: Masami Hiramatsu
- [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list
- From: Masami Hiramatsu
- Re: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list
- From: Steven Rostedt
- Re: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list
- From: Masami Hiramatsu
- [PATCH tracing/kprobes 0/6] tracing/kprobes: kprobe-based event tracer update and perf support
- Prev by Date: Re: Build error on arm in crypto/cast6.c
- Next by Date: Re: [PATCH tracing/kprobes 3/6] ftrace: Fix trace_remove_event_call() to lock trace_event_mutex
- Previous by thread: Re: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list
- Next by thread: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list take 2
- Index(es):
Relevant Pages
|
