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Tue, 19 Dec 2023 22:52:22 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6C4E03D0C4; Tue, 19 Dec 2023 22:52:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="T6xev0+F" X-Original-To: linux-kernel@vger.kernel.org Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98EF33DB8C; Tue, 19 Dec 2023 22:52:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20FADC433C7; Tue, 19 Dec 2023 22:52:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1703026326; bh=3d5e2aUYMvcozpuqzXim5hohQZk4N3N4SmHcyRdCntc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=T6xev0+FV3fDb/mYUfcl5Fmn8BtiZ468wXbAb/2c6ecNu9SAKggagRcWZY7DU4BBI 6PNDDEVEaW07keZLg21OseWmJGb/+sz0GN/KnB5mOpHWfyuBxrApnnNij7Maksf9Zi ja5m+cfCSsWf3VoeCiHYrSovHe7wYCQgLC4NZmRB6BPCCq23mB7XFxpsQTlMGoUIWY tcSuUirvRD747eZUmD/16B6qTTUS0QIO9+7Ix4XH3WIPBmrxXAXN9a9opmie35dSYc U2t6A7yooWn0Ta4uCpR/TPzAqd2ML79AK6EFzxxL0KNAbi3HgU+vLtWO1TiqkhAdTO RiazzkQJhSORQ== Date: Wed, 20 Dec 2023 07:51:59 +0900 From: Masami Hiramatsu (Google) To: Jiri Olsa Cc: Alexei Starovoitov , Steven Rostedt , Florent Revest , linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Sven Schnelle , Alexei Starovoitov , Arnaldo Carvalho de Melo , Daniel Borkmann , Alan Maguire , Mark Rutland , Peter Zijlstra , Thomas Gleixner , Guo Ren Subject: Re: [PATCH v5 24/34] fprobe: Use ftrace_regs in fprobe entry handler Message-Id: <20231220075159.a999e25dbf56f0334ba79249@kernel.org> In-Reply-To: References: <170290509018.220107.1347127510564358608.stgit@devnote2> <170290538307.220107.14964448383069008953.stgit@devnote2> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 19 Dec 2023 14:23:48 +0100 Jiri Olsa wrote: > On Mon, Dec 18, 2023 at 10:16:23PM +0900, Masami Hiramatsu (Google) wrote: > > SNIP > > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index 84e8a0f6e4e0..d3f8745d8ead 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -2503,7 +2503,7 @@ static int __init bpf_event_init(void) > > fs_initcall(bpf_event_init); > > #endif /* CONFIG_MODULES */ > > > > -#ifdef CONFIG_FPROBE > > +#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > > struct bpf_kprobe_multi_link { > > struct bpf_link link; > > struct fprobe fp; > > @@ -2733,10 +2733,14 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > > > > static int > > kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, > > - unsigned long ret_ip, struct pt_regs *regs, > > + unsigned long ret_ip, struct ftrace_regs *fregs, > > 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); > > @@ -3008,7 +3012,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > > kvfree(cookies); > > return err; > > } > > -#else /* !CONFIG_FPROBE */ > > +#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) > > { > > return -EOPNOTSUPP; > > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c > > index 6cd2a4e3afb8..f12569494d8a 100644 > > --- a/kernel/trace/fprobe.c > > +++ b/kernel/trace/fprobe.c > > @@ -46,7 +46,7 @@ static inline void __fprobe_handler(unsigned long ip, unsigned long parent_ip, > > } > > > > if (fp->entry_handler) > > - ret = fp->entry_handler(fp, ip, parent_ip, ftrace_get_regs(fregs), entry_data); > > + ret = fp->entry_handler(fp, ip, parent_ip, fregs, entry_data); > > > > /* If entry_handler returns !0, nmissed is not counted. */ > > if (rh) { > > @@ -182,7 +182,7 @@ static void fprobe_init(struct fprobe *fp) > > fp->ops.func = fprobe_kprobe_handler; > > else > > fp->ops.func = fprobe_handler; > > - fp->ops.flags |= FTRACE_OPS_FL_SAVE_REGS; > > + fp->ops.flags |= FTRACE_OPS_FL_SAVE_ARGS; > > so with this change you move to ftrace_caller trampoline, > but we need ftrace_regs_caller right? Yes, that's right. > > otherwise the (!regs) check in kprobe_multi_link_handler > will be allways true IIUC Ah, OK. So until we move to fgraph [28/34], keep this flag SAVE_REGS then kprobe_multi test will pass. OK, let me keep it so. Thank you! > > jirka > > > } > > > > static int fprobe_init_rethook(struct fprobe *fp, int num) > > diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c > > index 7d2ddbcfa377..ef6b36fd05ae 100644 > > --- a/kernel/trace/trace_fprobe.c > > +++ b/kernel/trace/trace_fprobe.c > > @@ -320,12 +320,16 @@ NOKPROBE_SYMBOL(fexit_perf_func); > > #endif /* CONFIG_PERF_EVENTS */ > > > > static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip, > > - unsigned long ret_ip, struct pt_regs *regs, > > + unsigned long ret_ip, struct ftrace_regs *fregs, > > void *entry_data) > > { > > struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp); > > + struct pt_regs *regs = ftrace_get_regs(fregs); > > int ret = 0; > > > > + if (!regs) > > + return 0; > > + > > if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE)) > > fentry_trace_func(tf, entry_ip, regs); > > #ifdef CONFIG_PERF_EVENTS > > diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c > > index 24de0e5ff859..ff607babba18 100644 > > --- a/lib/test_fprobe.c > > +++ b/lib/test_fprobe.c > > @@ -40,7 +40,7 @@ static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32)) > > > > static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip, > > unsigned long ret_ip, > > - struct pt_regs *regs, void *data) > > + struct ftrace_regs *fregs, void *data) > > { > > KUNIT_EXPECT_FALSE(current_test, preemptible()); > > /* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */ > > @@ -81,7 +81,7 @@ static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, > > > > static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip, > > unsigned long ret_ip, > > - struct pt_regs *regs, void *data) > > + struct ftrace_regs *fregs, void *data) > > { > > KUNIT_EXPECT_FALSE(current_test, preemptible()); > > return 0; > > diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c > > index 64e715e7ed11..1545a1aac616 100644 > > --- a/samples/fprobe/fprobe_example.c > > +++ b/samples/fprobe/fprobe_example.c > > @@ -50,7 +50,7 @@ static void show_backtrace(void) > > > > static int sample_entry_handler(struct fprobe *fp, unsigned long ip, > > unsigned long ret_ip, > > - struct pt_regs *regs, void *data) > > + struct ftrace_regs *fregs, void *data) > > { > > if (use_trace) > > /* > > -- Masami Hiramatsu (Google)