On Mon, 14 Oct 2019 12:59:23 +0200
Miroslav Benes <mbe...@suse.cz> wrote:
> int
> ftrace_enable_sysctl(struct ctl_table *table, int write,
> void __user *buffer, size_t *lenp,
> @@ -6740,8 +6754,6 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
> if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
> goto out;
>
> - last_ftrace_enabled = !!ftrace_enabled;
> -
> if (ftrace_enabled) {
>
> /* we are starting ftrace again */
> @@ -6752,12 +6764,19 @@ ftrace_enable_sysctl(struct ctl_table *table, int
> write,
> ftrace_startup_sysctl();
>
> } else {
> + if (is_permanent_ops_registered()) {
> + ftrace_enabled = last_ftrace_enabled;
Although this is not incorrect, but may be somewhat confusing.
At this location, last_ftrace_enabled is always true.
I'm thinking this would be better to simply set it to false here.
> + ret = -EBUSY;
> + goto out;
> + }
> +
> /* stopping ftrace calls (just send to ftrace_stub) */
> ftrace_trace_function = ftrace_stub;
>
> ftrace_shutdown_sysctl();
> }
>
> + last_ftrace_enabled = !!ftrace_enabled;
> out:
And move the assignment of last_ftrace_enabled to after the "out:"
label.
-- Steve
> mutex_unlock(&ftrace_lock);
> return ret;
