Re: [PATCH v2 2/4] fprobe: make fprobe_kprobe_handler recursion free

Peter Zijlstra
2023-05-16T09:16:17Z

On Tue, May 16, 2023 at 03:18:28PM +0800, Ze Gao wrote:

> +static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
> + struct ftrace_ops *ops, struct ftrace_regs *fregs)
> +{
> + struct fprobe *fp;
> + int bit;
> +
> + fp = container_of(ops, struct fprobe, ops);
> + if (fprobe_disabled(fp))
> + return;
> +
> + /* recursion detection has to go before any traceable function and
> + * all functions before this point should be marked as notrace
> + */
> + bit = ftrace_test_recursion_trylock(ip, parent_ip);
> + if (bit < 0) {
> + fp->nmissed++;
> + return;
> + }
> + __fprobe_handler(ip, parent_ip, ops, fregs);
> ftrace_test_recursion_unlock(bit);
> +
> }
> NOKPROBE_SYMBOL(fprobe_handler);
>
> static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,
> struct ftrace_ops *ops, struct ftrace_regs *fregs)
> {
> - struct fprobe *fp = container_of(ops, struct fprobe, ops);
> + struct fprobe *fp;
> + int bit;
> +
> + fp = container_of(ops, struct fprobe, ops);
> + if (fprobe_disabled(fp))
> + return;
> +
> + /* recursion detection has to go before any traceable function and
> + * all functions called before this point should be marked as notrace
> + */
> + bit = ftrace_test_recursion_trylock(ip, parent_ip);
> + if (bit < 0) {
> + fp->nmissed++;
> + return;
> + }

Please don't use this comment style; multi line comments go like:

/*
* Multi line comment ...
* ... is symmetric.
*/

Same for your next patch.