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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2013-05-09 14:44:14 +0900
committerSteven Rostedt <rostedt@goodmis.org>2013-05-09 11:26:01 -0400
commita5b85bd1557209b4ef18a8cf07e60a1ca3132468 (patch)
treef1c0c60e26e7f10e6e05cca9af1639bf651a7bf4 /kernel
parent2228768885e0b92c0f7b276cc61b8974e7aed724 (diff)
downloadlinux-linaro-stable-a5b85bd1557209b4ef18a8cf07e60a1ca3132468.tar.gz
tracing: Don't succeed if event_enable_func did not register anything
Return 0 instead of the number of activated ftrace function probes if event_enable_func succeeded and return an error code if it failed or did not register any functions. But it currently returns the number of registered functions and if it didn't register anything, it returns 0, but that is considered success. This also fixes the return value. As if it succeeds, it returns the number of functions that were enabled, which is returned back to the user in ftrace_regex_write (the write() return code). If only one function is enabled, then the return code of the write is one, and this can confuse the user program in thinking it only wrote 1 byte. Link: http://lkml.kernel.org/r/20130509054413.30398.55650.stgit@mhiramat-M0-7522 Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <tom.zanussi@intel.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> [ Rewrote change log to reflect that this fixes two bugs - SR ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_events.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 53582e982e51..44ac83614c3d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2061,8 +2061,11 @@ event_enable_func(struct ftrace_hash *hash,
if (ret < 0)
goto out_put;
ret = register_ftrace_function_probe(glob, ops, data);
- if (!ret)
+ if (!ret) {
+ ret = -ENOENT;
goto out_disable;
+ } else
+ ret = 0;
out:
mutex_unlock(&event_mutex);
return ret;