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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2013-05-16 20:48:49 +0900
committerSteven Rostedt <rostedt@goodmis.org>2013-05-16 11:01:16 -0400
commit6ed0106667d76589cb648c27edb4f4ffbf9d59ca (patch)
tree703a6db004b022ddebdfaf186c66e5bfabc03e5f /kernel
parentb62fdd97fcae17e483b005bafd13fadbd9840672 (diff)
downloadlinux-6ed0106667d76589cb648c27edb4f4ffbf9d59ca.tar.gz
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')
-rw-r--r--kernel/trace/trace_events.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7a0cf68027c..27963e2bf4b 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)