From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Florent Revest <revest@chromium.org>,
linux-trace-kernel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
bpf <bpf@vger.kernel.org>, Sven Schnelle <svens@linux.ibm.com>,
Alexei Starovoitov <ast@kernel.org>,
Jiri Olsa <jolsa@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Alan Maguire <alan.maguire@oracle.com>,
Mark Rutland <mark.rutland@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>, Guo Ren <guoren@kernel.org>
Subject: Re: [PATCH v9 29/36] bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled
Date: Thu, 25 Apr 2024 13:09:32 -0700 [thread overview]
Message-ID: <CAEf4BzZ2cZ-jJDj3Qdc4T_9FmCK21Ae-mr-d2RJRMtdUK8HOjQ@mail.gmail.com> (raw)
In-Reply-To: <171318568081.254850.16193015880509111721.stgit@devnote2>
On Mon, Apr 15, 2024 at 6:22 AM Masami Hiramatsu (Google)
<mhiramat@kernel.org> wrote:
>
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Enable kprobe_multi feature if CONFIG_FPROBE is enabled. The pt_regs is
> converted from ftrace_regs by ftrace_partial_regs(), thus some registers
> may always returns 0. But it should be enough for function entry (access
> arguments) and exit (access return value).
>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> Acked-by: Florent Revest <revest@chromium.org>
> ---
> Changes from previous series: NOTHING, Update against the new series.
> ---
> kernel/trace/bpf_trace.c | 22 +++++++++-------------
> 1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index e51a6ef87167..57b1174030c9 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2577,7 +2577,7 @@ static int __init bpf_event_init(void)
> fs_initcall(bpf_event_init);
> #endif /* CONFIG_MODULES */
>
> -#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS)
> +#ifdef CONFIG_FPROBE
> struct bpf_kprobe_multi_link {
> struct bpf_link link;
> struct fprobe fp;
> @@ -2600,6 +2600,8 @@ struct user_syms {
> char *buf;
> };
>
> +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs);
this is a waste if CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST=y, right?
Can we guard it?
> +
> static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt)
> {
> unsigned long __user usymbol;
> @@ -2792,13 +2794,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx)
>
> static int
> kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
> - unsigned long entry_ip, struct pt_regs *regs)
> + unsigned long entry_ip, struct ftrace_regs *fregs)
> {
> struct bpf_kprobe_multi_run_ctx run_ctx = {
> .link = link,
> .entry_ip = entry_ip,
> };
> struct bpf_run_ctx *old_run_ctx;
> + struct pt_regs *regs;
> int err;
>
> if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
> @@ -2809,6 +2812,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
>
> migrate_disable();
> rcu_read_lock();
> + regs = ftrace_partial_regs(fregs, this_cpu_ptr(&bpf_kprobe_multi_pt_regs));
and then pass NULL if defined(CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST)?
> old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> err = bpf_prog_run(link->link.prog, regs);
> bpf_reset_run_ctx(old_run_ctx);
> @@ -2826,13 +2830,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
> void *data)
> {
> struct bpf_kprobe_multi_link *link;
> - struct pt_regs *regs = ftrace_get_regs(fregs);
> -
> - if (!regs)
> - return 0;
>
> link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs);
> return 0;
> }
>
> @@ -2842,13 +2842,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
> void *data)
> {
> struct bpf_kprobe_multi_link *link;
> - struct pt_regs *regs = ftrace_get_regs(fregs);
> -
> - if (!regs)
> - return;
>
> link = container_of(fp, struct bpf_kprobe_multi_link, fp);
> - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
> + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs);
> }
>
> static int symbols_cmp_r(const void *a, const void *b, const void *priv)
> @@ -3107,7 +3103,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> kvfree(cookies);
> return err;
> }
> -#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */
> +#else /* !CONFIG_FPROBE */
> int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
> {
> return -EOPNOTSUPP;
>
>
next prev parent reply other threads:[~2024-04-25 20:09 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-15 12:48 [PATCH v9 00/36] tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph Masami Hiramatsu (Google)
2024-04-15 12:49 ` [PATCH v9 01/36] tracing: Add a comment about ftrace_regs definition Masami Hiramatsu (Google)
2024-04-24 12:23 ` Florent Revest
2024-04-24 13:19 ` Florent Revest
2024-04-24 14:31 ` Masami Hiramatsu
2024-04-15 12:49 ` [PATCH v9 02/36] tracing: Rename ftrace_regs_return_value to ftrace_regs_get_return_value Masami Hiramatsu (Google)
2024-04-15 12:49 ` [PATCH v9 03/36] x86: tracing: Add ftrace_regs definition in the header Masami Hiramatsu (Google)
2024-04-15 12:49 ` [PATCH v9 04/36] function_graph: Convert ret_stack to a series of longs Masami Hiramatsu (Google)
2024-04-15 12:49 ` [PATCH v9 05/36] fgraph: Use BUILD_BUG_ON() to make sure we have structures divisible by long Masami Hiramatsu (Google)
2024-04-15 12:50 ` [PATCH v9 06/36] function_graph: Add an array structure that will allow multiple callbacks Masami Hiramatsu (Google)
2024-04-15 12:50 ` [PATCH v9 07/36] function_graph: Allow multiple users to attach to function graph Masami Hiramatsu (Google)
2024-04-20 3:52 ` Steven Rostedt
2024-04-20 8:56 ` Masami Hiramatsu
2024-04-15 12:50 ` [PATCH v9 08/36] function_graph: Remove logic around ftrace_graph_entry and return Masami Hiramatsu (Google)
2024-04-15 12:50 ` [PATCH v9 09/36] ftrace/function_graph: Pass fgraph_ops to function graph callbacks Masami Hiramatsu (Google)
2024-04-15 12:50 ` [PATCH v9 10/36] ftrace: Allow function_graph tracer to be enabled in instances Masami Hiramatsu (Google)
2024-04-15 12:51 ` [PATCH v9 11/36] ftrace: Allow ftrace startup flags exist without dynamic ftrace Masami Hiramatsu (Google)
2024-04-15 12:51 ` [PATCH v9 12/36] function_graph: Have the instances use their own ftrace_ops for filtering Masami Hiramatsu (Google)
2024-04-15 12:51 ` [PATCH v9 13/36] function_graph: Use a simple LRU for fgraph_array index number Masami Hiramatsu (Google)
2024-04-15 12:51 ` [PATCH v9 14/36] function_graph: Add "task variables" per task for fgraph_ops Masami Hiramatsu (Google)
2024-04-15 12:51 ` [PATCH v9 15/36] function_graph: Move set_graph_function tests to shadow stack global var Masami Hiramatsu (Google)
2024-04-15 12:52 ` [PATCH v9 16/36] function_graph: Move graph depth stored data " Masami Hiramatsu (Google)
2024-04-15 12:52 ` [PATCH v9 17/36] function_graph: Move graph notrace bit " Masami Hiramatsu (Google)
2024-04-15 12:52 ` [PATCH v9 18/36] function_graph: Implement fgraph_reserve_data() and fgraph_retrieve_data() Masami Hiramatsu (Google)
2024-04-15 12:52 ` [PATCH v9 19/36] function_graph: Add selftest for passing local variables Masami Hiramatsu (Google)
2024-04-15 12:52 ` [PATCH v9 20/36] ftrace: Add multiple fgraph storage selftest Masami Hiramatsu (Google)
2024-04-15 12:53 ` [PATCH v9 21/36] function_graph: Pass ftrace_regs to entryfunc Masami Hiramatsu (Google)
2024-04-15 12:53 ` [PATCH v9 22/36] function_graph: Replace fgraph_ret_regs with ftrace_regs Masami Hiramatsu (Google)
2024-04-15 12:53 ` [PATCH v9 23/36] function_graph: Pass ftrace_regs to retfunc Masami Hiramatsu (Google)
2024-04-15 12:53 ` [PATCH v9 24/36] fprobe: Use ftrace_regs in fprobe entry handler Masami Hiramatsu (Google)
2024-04-15 12:53 ` [PATCH v9 25/36] fprobe: Use ftrace_regs in fprobe exit handler Masami Hiramatsu (Google)
2024-04-15 12:54 ` [PATCH v9 26/36] tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs Masami Hiramatsu (Google)
2024-04-15 12:54 ` [PATCH v9 27/36] tracing: Add ftrace_fill_perf_regs() for perf event Masami Hiramatsu (Google)
2024-04-15 12:54 ` [PATCH v9 28/36] tracing/fprobe: Enable fprobe events with CONFIG_DYNAMIC_FTRACE_WITH_ARGS Masami Hiramatsu (Google)
2024-04-15 12:54 ` [PATCH v9 29/36] bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled Masami Hiramatsu (Google)
2024-04-25 20:09 ` Andrii Nakryiko [this message]
2024-04-29 14:57 ` Masami Hiramatsu
2024-04-15 12:54 ` [PATCH v9 30/36] ftrace: Add CONFIG_HAVE_FTRACE_GRAPH_FUNC Masami Hiramatsu (Google)
2024-04-15 12:55 ` [PATCH v9 31/36] fprobe: Rewrite fprobe on function-graph tracer Masami Hiramatsu (Google)
2024-04-15 12:55 ` [PATCH v9 32/36] tracing/fprobe: Remove nr_maxactive from fprobe Masami Hiramatsu (Google)
2024-04-15 12:55 ` [PATCH v9 33/36] selftests: ftrace: Remove obsolate maxactive syntax check Masami Hiramatsu (Google)
2024-04-15 12:55 ` [PATCH v9 34/36] selftests/ftrace: Add a test case for repeating register/unregister fprobe Masami Hiramatsu (Google)
2024-04-15 12:55 ` [PATCH v9 35/36] Documentation: probes: Update fprobe on function-graph tracer Masami Hiramatsu (Google)
2024-04-15 12:55 ` [PATCH v9 36/36] fgraph: Skip recording calltime/rettime if it is not nneeded Masami Hiramatsu (Google)
2024-04-25 20:15 ` Andrii Nakryiko
2024-04-29 14:56 ` Masami Hiramatsu
2024-04-19 5:36 ` [PATCH v9 00/36] tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph Masami Hiramatsu
2024-04-19 8:01 ` Steven Rostedt
2024-04-24 13:35 ` Florent Revest
2024-04-25 15:10 ` Masami Hiramatsu
2024-04-25 20:31 ` Andrii Nakryiko
2024-04-28 23:25 ` Steven Rostedt
2024-04-29 20:28 ` Andrii Nakryiko
2024-04-29 13:51 ` Masami Hiramatsu
2024-04-29 20:25 ` Andrii Nakryiko
2024-04-30 13:32 ` Masami Hiramatsu
2024-04-30 16:29 ` Andrii Nakryiko
2024-05-02 2:06 ` Masami Hiramatsu
2024-05-07 21:04 ` Andrii Nakryiko
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