5.4-stable review patch. If anyone has any objections, please let me know.
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From: Siddh Raman Pant siddh.raman.pant@oracle.com
This reverts commit 8ffd5590f4d6ef5460acbeac7fbdff7025f9b419 which is commit 0958b33ef5a04ed91f61cef4760ac412080c4e08 upstream.
The change has an incorrect assumption about the return value because in the current stable trees for versions 5.15 and before, the following commit responsible for making 0 a success value is not present: b8cc44a4d3c1 ("tracing: Remove logic for registering multiple event triggers at a time")
The return value should be 0 on failure in the current tree, because in the functions event_trigger_callback() and event_enable_trigger_func(), we have:
ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file); /* * The above returns on success the # of functions enabled, * but if it didn't find any functions it returns zero. * Consider no functions a failure too. */ if (!ret) { ret = -ENOENT;
Cc: stable@kernel.org # 5.15, 5.10, 5.4, 4.19 Signed-off-by: Siddh Raman Pant siddh.raman.pant@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/trace_events_trigger.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
--- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -1140,10 +1140,8 @@ register_snapshot_trigger(char *glob, st struct event_trigger_data *data, struct trace_event_file *file) { - int ret = tracing_alloc_snapshot_instance(file->tr); - - if (ret < 0) - return ret; + if (tracing_alloc_snapshot_instance(file->tr) != 0) + return 0;
return register_trigger(glob, ops, data, file); }