From nobody Sun Feb 8 09:10:35 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41CCAC001DB for ; Sat, 5 Aug 2023 14:59:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229925AbjHEO7O (ORCPT ); Sat, 5 Aug 2023 10:59:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229884AbjHEO7L (ORCPT ); Sat, 5 Aug 2023 10:59:11 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA70F44A1; Sat, 5 Aug 2023 07:58:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4D2EF601D0; Sat, 5 Aug 2023 14:58:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1491FC433C8; Sat, 5 Aug 2023 14:58:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691247533; bh=zlG4XdXdEpC54rcZoPhBS/p5nrcyfvD1Z3WKRvALoqk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dtQWDnhA/NNtISReu5UUc99txh1LiTHylfhpoJVKtscA39myvE3AjoY5vdFp+9saC xnoUS1YK5XUGkOlYCC3UmM/pNaW783FDsz0WtBtCcNpu5wLwQRVG1V4wpTcOVHEvOE pKg3I9bPvV1xchqwNA9yzgoV9vtzu1pxTMTt7i2dIYBftfJ0RGmTKntCAMu42N6/gW AOGDiWEbqU/e8yEtS5oU2VEAjpL2CKhpLNOAry8SW56hqnZzQOC5iGYzcRpNQTHxZu HjaIeks7HQPRENMJKOesbKGi3o1P+7vfUFcvCDrtyz7tbkHdqWE9gEVOIL2038uDX2 VxsWES0gtZKug== From: "Masami Hiramatsu (Google)" To: Alexei Starovoitov , Steven Rostedt , Florent Revest Cc: linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Sven Schnelle , Alexei Starovoitov , Jiri Olsa , Arnaldo Carvalho de Melo , Daniel Borkmann , Alan Maguire , Mark Rutland , Peter Zijlstra , Thomas Gleixner Subject: [RFC PATCH 5/5] bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled Date: Sat, 5 Aug 2023 23:58:47 +0900 Message-Id: <169124752752.186149.5928887430024942007.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <169124746774.186149.2326708176801468806.stgit@devnote2> References: <169124746774.186149.2326708176801468806.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masami Hiramatsu (Google) 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) --- 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 99c5f95360f9..0725272a3de2 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2460,7 +2460,7 @@ static int __init bpf_event_init(void) fs_initcall(bpf_event_init); #endif /* CONFIG_MODULES */ =20 -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +#ifdef CONFIG_FPROBE struct bpf_kprobe_multi_link { struct bpf_link link; struct fprobe fp; @@ -2482,6 +2482,8 @@ struct user_syms { char *buf; }; =20 +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs); + static int copy_user_syms(struct user_syms *us, unsigned long __user *usym= s, u32 cnt) { unsigned long __user usymbol; @@ -2623,13 +2625,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run= _ctx *ctx) =20 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 =3D { .link =3D link, .entry_ip =3D entry_ip, }; struct bpf_run_ctx *old_run_ctx; + struct pt_regs *regs; int err; =20 if (unlikely(__this_cpu_inc_return(bpf_prog_active) !=3D 1)) { @@ -2639,6 +2642,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_li= nk *link, =20 migrate_disable(); rcu_read_lock(); + regs =3D ftrace_partial_regs(fregs, this_cpu_ptr(&bpf_kprobe_multi_pt_reg= s)); old_run_ctx =3D bpf_set_run_ctx(&run_ctx.run_ctx); err =3D bpf_prog_run(link->link.prog, regs); bpf_reset_run_ctx(old_run_ctx); @@ -2656,13 +2660,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigne= d long fentry_ip, void *data) { struct bpf_kprobe_multi_link *link; - struct pt_regs *regs =3D ftrace_get_regs(fregs); - - if (!regs) - return 0; =20 link =3D 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; } =20 @@ -2672,13 +2672,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, un= signed long fentry_ip, void *data) { struct bpf_kprobe_multi_link *link; - struct pt_regs *regs =3D ftrace_get_regs(fregs); - - if (!regs) - return; =20 link =3D 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); } =20 static int symbols_cmp_r(const void *a, const void *b, const void *priv) @@ -2918,7 +2914,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr= *attr, struct bpf_prog *pr kvfree(cookies); return err; } -#else /* !CONFIG_DYNAMIC_FTRACE_WITH_REGS */ +#else /* !CONFIG_FPROBE */ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_pr= og *prog) { return -EOPNOTSUPP;