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| author |   Chunyu Hu <chuhu@redhat.com> | 2016-03-08 21:37:01 +0800 |
|---|---|---|
| committer |   Steven Rostedt <rostedt@goodmis.org> | 2016-03-08 11:19:08 -0500 |
| commit | d39cdd2036a63eef17a14efbd969405ca5612886 (patch) | |
| tree | 547098658fa6d9e6dba8ffe73ccd756ba5638668 /kernel/trace/trace.h | |
| parent | Linux 4.5-rc7 (diff) | |
| download | linux-dev-d39cdd2036a63eef17a14efbd969405ca5612886.tar.xz linux-dev-d39cdd2036a63eef17a14efbd969405ca5612886.zip | |
tracing: Make tracer_flags use the right set_flag callback
When I was updating the ftrace_stress test of ltp. I encountered
a strange phenomemon, excute following steps:
echo nop > /sys/kernel/debug/tracing/current_tracer
echo 0 > /sys/kernel/debug/tracing/options/funcgraph-cpu
bash: echo: write error: Invalid argument
check dmesg:
[ 1024.903855] nop_test_refuse flag set to 0: we refuse.Now cat trace_options to see the result
The reason is that the trace option test will randomly setup trace
option under tracing/options no matter what the current_tracer is.
but the set_tracer_option is always using the set_flag callback
from the current_tracer. This patch adds a pointer to tracer_flags
and make it point to the tracer it belongs to. When the option is
setup, the set_flag of the right tracer will be used no matter
what the the current_tracer is.
And the old dummy_tracer_flags is used for all the tracers which
doesn't have a tracer_flags, having issue to use it to save the
pointer of a tracer. So remove it and use dynamic dummy tracer_flags
for tracers needing a dummy tracer_flags, as a result, there are no
tracers sharing tracer_flags, so remove the check code.
And save the current tracer to trace_option_dentry seems not good as
it may waste mem space when mount the debug/trace fs more than one time.
Link: http://lkml.kernel.org/r/1457444222-8654-1-git-send-email-chuhu@redhat.com
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
[ Fixed up function tracer options to work with the change ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.h')
| -rw-r--r-- | kernel/trace/trace.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 8414fa40bf27..b4cae47f283e 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -345,6 +345,7 @@ struct tracer_opt { struct tracer_flags { u32 val; struct tracer_opt *opts; + struct tracer *trace; }; /* Makes more easy to define a tracer opt */ |