diff options
author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2013-05-16 07:48:49 -0400 |
---|---|---|
committer | Steven Rostedt <rostedt@goodmis.org> | 2013-05-16 11:01:16 -0400 |
commit | 6ed0106667d76589cb648c27edb4f4ffbf9d59ca (patch) | |
tree | 703a6db004b022ddebdfaf186c66e5bfabc03e5f /kernel/trace | |
parent | b62fdd97fcae17e483b005bafd13fadbd9840672 (diff) |
tracing: Return -EBUSY when event_enable_func() fails to get module
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 that the module is being removed at that time.
Link: http://lkml.kernel.org/r/20130516114848.13508.97899.stgit@mhiramat-M0-7522
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r-- | kernel/trace/trace_events.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 7a0cf68027cc..27963e2bf4bf 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c | |||
@@ -2072,8 +2072,10 @@ event_enable_func(struct ftrace_hash *hash, | |||
2072 | out_reg: | 2072 | out_reg: |
2073 | /* Don't let event modules unload while probe registered */ | 2073 | /* Don't let event modules unload while probe registered */ |
2074 | ret = try_module_get(file->event_call->mod); | 2074 | ret = try_module_get(file->event_call->mod); |
2075 | if (!ret) | 2075 | if (!ret) { |
2076 | ret = -EBUSY; | ||
2076 | goto out_free; | 2077 | goto out_free; |
2078 | } | ||
2077 | 2079 | ||
2078 | ret = __ftrace_event_enable_disable(file, 1, 1); | 2080 | ret = __ftrace_event_enable_disable(file, 1, 1); |
2079 | if (ret < 0) | 2081 | if (ret < 0) |