From nobody Sat Sep 13 20:31:48 2025 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 BC6C3C38142 for ; Tue, 31 Jan 2023 16:15:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231892AbjAaQPZ (ORCPT ); Tue, 31 Jan 2023 11:15:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230522AbjAaQPW (ORCPT ); Tue, 31 Jan 2023 11:15:22 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA47C53E75; Tue, 31 Jan 2023 08:15:18 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 95543B81CD9; Tue, 31 Jan 2023 16:15:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 024F1C433D2; Tue, 31 Jan 2023 16:15:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675181716; bh=xoo+m5nnKJwCHyu3Pdsr89f7T1zFTE7ZqK87QXapMiI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kiffb93JpdmNsqrQqXmR/qKIzMxBFs1b/1xGVTa1YPDXQ3GDU88lXebTBIM57jISV rRC4A3/BYJuwzsrbh3IIbiS5aOSdpf26kz8GClgrZpahT9B9aLAsoQt189rG5UF5lO co0VyHtcBLoVi6bkD5MJlx1Inyq/AJ+qEVnaxB8Xyuczq+WwhERmXnBuHHWI3/En/q JSloERMawcPgEcKU8szdgHvA7LyRORwKiphsfxxs7alwtut6ORhCy51DuXJACeSDN4 I9X9T+DKX6P+UEqaEFMInfcRyvk1UGJPBx9m0H04PjvnNLMyO8Z6dwUsXcNjfiLeXc R6iMlaDFf7ZfQ== From: "Masami Hiramatsu (Google)" To: linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Steven Rostedt , mhiramat@kernel.org, Florent Revest , Mark Rutland , Will Deacon Subject: [PATCH v2 01/10] fprobe: Pass entry_data to handlers Date: Wed, 1 Feb 2023 01:15:12 +0900 Message-Id: <167518171273.336834.17666863442580618765.stgit@mhiramat.roam.corp.google.com> X-Mailer: git-send-email 2.39.1.456.gfc5497dd1b-goog In-Reply-To: <167518170369.336834.15310137713178284219.stgit@mhiramat.roam.corp.google.com> References: <167518170369.336834.15310137713178284219.stgit@mhiramat.roam.corp.google.com> 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) Pass the private entry_data to the entry and exit handlers so that they can share the context data, something like saved function arguments etc. User must specify the private entry_data size by @entry_data_size field before registering the fprobe. Signed-off-by: Masami Hiramatsu (Google) --- include/linux/fprobe.h | 8 ++++++-- kernel/trace/bpf_trace.c | 2 +- kernel/trace/fprobe.c | 21 ++++++++++++++------- lib/test_fprobe.c | 6 ++++-- samples/fprobe/fprobe_example.c | 6 ++++-- 5 files changed, 29 insertions(+), 14 deletions(-) diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h index 1c2bde0ead73..e0d4e6136249 100644 --- a/include/linux/fprobe.h +++ b/include/linux/fprobe.h @@ -13,6 +13,7 @@ * @nmissed: The counter for missing events. * @flags: The status flag. * @rethook: The rethook data structure. (internal data) + * @entry_data_size: The private data storage size. * @entry_handler: The callback function for function entry. * @exit_handler: The callback function for function exit. */ @@ -29,9 +30,12 @@ struct fprobe { unsigned long nmissed; unsigned int flags; struct rethook *rethook; + size_t entry_data_size; =20 - void (*entry_handler)(struct fprobe *fp, unsigned long entry_ip, struct p= t_regs *regs); - void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip, struct pt= _regs *regs); + void (*entry_handler)(struct fprobe *fp, unsigned long entry_ip, + struct pt_regs *regs, void *entry_data); + void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip, + struct pt_regs *regs, void *entry_data); }; =20 /* This fprobe is soft-disabled. */ diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f47274de012b..834c0a7efcdb 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2649,7 +2649,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_li= nk *link, =20 static void kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, - struct pt_regs *regs) + struct pt_regs *regs, void *data) { struct bpf_kprobe_multi_link *link; =20 diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index e8143e368074..fa25d09c9d57 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -17,14 +17,16 @@ struct fprobe_rethook_node { struct rethook_node node; unsigned long entry_ip; + char data[]; }; =20 static void fprobe_handler(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct ftrace_regs *fregs) { struct fprobe_rethook_node *fpr; - struct rethook_node *rh; + struct rethook_node *rh =3D NULL; struct fprobe *fp; + void *entry_data =3D NULL; int bit; =20 fp =3D container_of(ops, struct fprobe, ops); @@ -37,9 +39,6 @@ static void fprobe_handler(unsigned long ip, unsigned lon= g parent_ip, return; } =20 - if (fp->entry_handler) - fp->entry_handler(fp, ip, ftrace_get_regs(fregs)); - if (fp->exit_handler) { rh =3D rethook_try_get(fp->rethook); if (!rh) { @@ -48,9 +47,16 @@ static void fprobe_handler(unsigned long ip, unsigned lo= ng parent_ip, } fpr =3D container_of(rh, struct fprobe_rethook_node, node); fpr->entry_ip =3D ip; - rethook_hook(rh, ftrace_get_regs(fregs), true); + if (fp->entry_data_size) + entry_data =3D fpr->data; } =20 + if (fp->entry_handler) + fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data); + + if (rh) + rethook_hook(rh, ftrace_get_regs(fregs), true); + out: ftrace_test_recursion_unlock(bit); } @@ -81,7 +87,8 @@ static void fprobe_exit_handler(struct rethook_node *rh, = void *data, =20 fpr =3D container_of(rh, struct fprobe_rethook_node, node); =20 - fp->exit_handler(fp, fpr->entry_ip, regs); + fp->exit_handler(fp, fpr->entry_ip, regs, + fp->entry_data_size ? (void *)fpr->data : NULL); } NOKPROBE_SYMBOL(fprobe_exit_handler); =20 @@ -146,7 +153,7 @@ static int fprobe_init_rethook(struct fprobe *fp, int n= um) for (i =3D 0; i < size; i++) { struct fprobe_rethook_node *node; =20 - node =3D kzalloc(sizeof(*node), GFP_KERNEL); + node =3D kzalloc(sizeof(*node) + fp->entry_data_size, GFP_KERNEL); if (!node) { rethook_free(fp->rethook); fp->rethook =3D NULL; diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c index 1fb56cf5e5ce..e4f65d114ed2 100644 --- a/lib/test_fprobe.c +++ b/lib/test_fprobe.c @@ -30,7 +30,8 @@ static noinline u32 fprobe_selftest_target2(u32 value) return (value / div_factor) + 1; } =20 -static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, = struct pt_regs *regs) +static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, + struct pt_regs *regs, void *data) { KUNIT_EXPECT_FALSE(current_test, preemptible()); /* This can be called on the fprobe_selftest_target and the fprobe_selfte= st_target2 */ @@ -39,7 +40,8 @@ static notrace void fp_entry_handler(struct fprobe *fp, u= nsigned long ip, struct entry_val =3D (rand1 / div_factor); } =20 -static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, s= truct pt_regs *regs) +static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, + struct pt_regs *regs, void *data) { unsigned long ret =3D regs_return_value(regs); =20 diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_exampl= e.c index e22da8573116..dd794990ad7e 100644 --- a/samples/fprobe/fprobe_example.c +++ b/samples/fprobe/fprobe_example.c @@ -48,7 +48,8 @@ static void show_backtrace(void) stack_trace_print(stacks, len, 24); } =20 -static void sample_entry_handler(struct fprobe *fp, unsigned long ip, stru= ct pt_regs *regs) +static void sample_entry_handler(struct fprobe *fp, unsigned long ip, + struct pt_regs *regs, void *data) { if (use_trace) /* @@ -63,7 +64,8 @@ static void sample_entry_handler(struct fprobe *fp, unsig= ned long ip, struct pt_ show_backtrace(); } =20 -static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struc= t pt_regs *regs) +static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struc= t pt_regs *regs, + void *data) { unsigned long rip =3D instruction_pointer(regs);