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Date: Sat, 31 Aug 2013 12:47:23 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Jiri Olsa <jolsa@...hat.com>
Subject: Re: [RFC][PATCH 07/18 v2] ftrace: Add selftest to check if RCU
unsafe functions are filtered properly
On Sat, Aug 31, 2013 at 01:11:24AM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@...dmis.org>
>
> Add a boot time start up test that has a RCU safe ftrace_ops as well
> as an unsafe one. Make sure the RCU safe ops can trace RCU unsafe
> functions while the unsafe ftrace_ops can not.
>
> Cc: Jiri Olsa <jolsa@...hat.com>
> Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> Signed-off-by: Steven Rostedt <rostedt@...dmis.org>
Acked-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> ---
> kernel/trace/trace.h | 2 +
> kernel/trace/trace_selftest.c | 94 +++++++++++++++++++++++++++++++++
> kernel/trace/trace_selftest_dynamic.c | 7 +++
> 3 files changed, 103 insertions(+)
>
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index 502fed7..3578be6 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -648,6 +648,8 @@ extern unsigned long ftrace_update_tot_cnt;
> extern int DYN_FTRACE_TEST_NAME(void);
> #define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2
> extern int DYN_FTRACE_TEST_NAME2(void);
> +#define DYN_FTRACE_TEST_RCU_UNSAFE trace_selftest_dynamic_test_rcu_unsafe
> +extern int DYN_FTRACE_TEST_RCU_UNSAFE(void);
>
> extern bool ring_buffer_expanded;
> extern bool tracing_selftest_disabled;
> diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
> index a7329b7..eeacb47 100644
> --- a/kernel/trace/trace_selftest.c
> +++ b/kernel/trace/trace_selftest.c
> @@ -185,6 +185,97 @@ static void reset_counts(void)
> trace_selftest_test_dyn_cnt = 0;
> }
>
> +static struct ftrace_ops ftrace_rcu_safe_ops = {
> + .func = trace_selftest_test_probe1_func,
> + .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_RCU_SAFE,
> +};
> +
> +static struct ftrace_ops ftrace_rcu_unsafe_ops = {
> + .func = trace_selftest_test_probe2_func,
> + .flags = FTRACE_OPS_FL_RECURSION_SAFE,
> +};
> +
> +static int test_rcu_safe_unsafe(void)
> +{
> + int save_ftrace_enabled = ftrace_enabled;
> + char *func_name;
> + int len;
> + int ret = 0;
> +
> + printk(KERN_CONT "PASSED\n");
> + pr_info("Testing ftrace rcu safe unsafe: ");
> +
> + ftrace_enabled = 1;
> +
> + trace_selftest_test_probe1_cnt = 0;
> + trace_selftest_test_probe2_cnt = 0;
> +
> + func_name = "*" __stringify(DYN_FTRACE_TEST_RCU_UNSAFE);
> + len = strlen(func_name);
> +
> + ftrace_set_filter(&ftrace_rcu_safe_ops, func_name, len, 1);
> + ftrace_set_filter(&ftrace_rcu_unsafe_ops, func_name, len, 1);
> +
> + /* Do single registrations first */
> + register_ftrace_function(&ftrace_rcu_safe_ops);
> +
> + DYN_FTRACE_TEST_RCU_UNSAFE();
> +
> + unregister_ftrace_function(&ftrace_rcu_safe_ops);
> +
> + if (trace_selftest_test_probe1_cnt != 1) {
> + printk(KERN_CONT "rcu_safe expected 1 call but had %d ",
> + trace_selftest_test_probe1_cnt);
> + goto out;
> + }
> +
> + register_ftrace_function(&ftrace_rcu_unsafe_ops);
> +
> + DYN_FTRACE_TEST_RCU_UNSAFE();
> +
> + unregister_ftrace_function(&ftrace_rcu_unsafe_ops);
> +
> + if (trace_selftest_test_probe2_cnt != 0) {
> + printk(KERN_CONT "rcu_safe expected 0 calls but had %d ",
> + trace_selftest_test_probe2_cnt);
> + goto out;
> + }
> +
> + /* Run both together, which uses the list op */
> +
> + trace_selftest_test_probe1_cnt = 0;
> + trace_selftest_test_probe2_cnt = 0;
> +
> + register_ftrace_function(&ftrace_rcu_safe_ops);
> + register_ftrace_function(&ftrace_rcu_unsafe_ops);
> +
> + DYN_FTRACE_TEST_RCU_UNSAFE();
> + DYN_FTRACE_TEST_RCU_UNSAFE();
> + DYN_FTRACE_TEST_RCU_UNSAFE();
> +
> + unregister_ftrace_function(&ftrace_rcu_unsafe_ops);
> + unregister_ftrace_function(&ftrace_rcu_safe_ops);
> +
> +
> + if (trace_selftest_test_probe1_cnt != 3) {
> + printk(KERN_CONT "rcu_safe expected 3 calls but had %d ",
> + trace_selftest_test_probe1_cnt);
> + goto out;
> + }
> +
> + if (trace_selftest_test_probe2_cnt != 0) {
> + printk(KERN_CONT "rcu_safe expected 0 calls but had %d ",
> + trace_selftest_test_probe2_cnt);
> + goto out;
> + }
> +
> + ret = 0;
> + out:
> + ftrace_enabled = save_ftrace_enabled;
> +
> + return ret;
> +}
> +
> static int trace_selftest_ops(int cnt)
> {
> int save_ftrace_enabled = ftrace_enabled;
> @@ -401,6 +492,9 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
> if (!ret)
> ret = trace_selftest_ops(2);
>
> + if (!ret)
> + ret = test_rcu_safe_unsafe();
> +
> return ret;
> }
>
> diff --git a/kernel/trace/trace_selftest_dynamic.c b/kernel/trace/trace_selftest_dynamic.c
> index b4c475a..5eefa56 100644
> --- a/kernel/trace/trace_selftest_dynamic.c
> +++ b/kernel/trace/trace_selftest_dynamic.c
> @@ -11,3 +11,10 @@ int DYN_FTRACE_TEST_NAME2(void)
> /* used to call mcount */
> return 0;
> }
> +
> +int trace_selftest_dynamic_test_rcu_unsafe(void)
> +{
> + /* used to call mcount */
> + return 0;
> +}
> +FTRACE_UNSAFE_RCU(trace_selftest_dynamic_test_rcu_unsafe);
> --
> 1.7.10.4
>
>
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