Messages in this thread Patch in this message | | | Subject | [PATCH v2 1/5] [BUGFIX] tracing: Returns -EBUSY when event_enable_func fails to get module | From | Masami Hiramatsu <> | Date | Wed, 22 May 2013 11:19:09 +0900 |
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Since try_module_get returns false( = 0) when it fails to pindown a module, event_enable_func() returns 0 which means "succeed". This can cause a kernel panic when the entry is removed, because the event is already released.
This fixes the bug by returning -EBUSY, because the reason why it fails is under removing module at that time.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> --- kernel/trace/trace_events.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 7a0cf68..27963e2 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2072,8 +2072,10 @@ event_enable_func(struct ftrace_hash *hash, out_reg: /* Don't let event modules unload while probe registered */ ret = try_module_get(file->event_call->mod); - if (!ret) + if (!ret) { + ret = -EBUSY; goto out_free; + } ret = __ftrace_event_enable_disable(file, 1, 1); if (ret < 0)
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