From patchwork Tue Nov 8 15:49:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13036499 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 60A57C4332F for ; Tue, 8 Nov 2022 15:50:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234506AbiKHPuI (ORCPT ); Tue, 8 Nov 2022 10:50:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234563AbiKHPuD (ORCPT ); Tue, 8 Nov 2022 10:50:03 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 156515C758; Tue, 8 Nov 2022 07:50:03 -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 dfw.source.kernel.org (Postfix) with ESMTPS id A639061646; Tue, 8 Nov 2022 15:50:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFA17C4314C; Tue, 8 Nov 2022 15:50:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667922602; bh=MHHslVLlQavpqBMVzMqaHP+31Fg1qy0ktAOkl4B6S/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tVLKzFOmK5FuxvbyRCCUUgY60moICzyWNKSZkxSo7BZhvvUDaBrbCDOFNTwj9Crt/ /ZKyzCDMnssQo5EULcoTOODkCBlyrM8rF/hkDTWlHxnPv1OZMJ9UJ6Lat1R0hdNnDx dCi/ny1zmagXr3iueZvaGmlWiFbGPJL2ufnN+Y3/F3XunFVTm7WLMH6GcpZgfLHkW+ J/ubXcgbQ1BHmjAMLHrm9iX637k2XhEXg59yJ/WMuRP/OQORDX/OZadkFCjb0mnBZE 9oMtOaVAlQa6WdSSgetaGKoINIqxoDTVuCXyxUAwz82lZ1hjH1Qx/VrlrDFb5ZNmCz s+SHkxH5ejMNg== 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: [RFC PATCH 5/9] fprobe: Skip exit_handler if entry_handler returns !0 Date: Wed, 9 Nov 2022 00:49:58 +0900 Message-Id: <166792259869.919356.8529453996904377437.stgit@devnote3> X-Mailer: git-send-email 2.38.1.431.g37b22c650d-goog In-Reply-To: <166792255429.919356.14116090269057513181.stgit@devnote3> References: <166792255429.919356.14116090269057513181.stgit@devnote3> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org From: Masami Hiramatsu (Google) Skip hooking function return and calling exit_handler if the entry_handler() returns !0. Signed-off-by: Masami Hiramatsu (Google) --- include/linux/fprobe.h | 4 ++-- kernel/trace/bpf_trace.c | 15 +++++++++++++-- kernel/trace/fprobe.c | 14 +++++++++----- lib/test_fprobe.c | 7 +++++-- samples/fprobe/fprobe_example.c | 5 +++-- 5 files changed, 32 insertions(+), 13 deletions(-) diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h index 678f741a7b33..47fefc7f363b 100644 --- a/include/linux/fprobe.h +++ b/include/linux/fprobe.h @@ -34,8 +34,8 @@ struct fprobe { size_t entry_data_size; int nr_maxactive; - void (*entry_handler)(struct fprobe *fp, unsigned long entry_ip, - struct pt_regs *regs, void *entry_data); + int (*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); }; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 68c369452680..dadcddb6a429 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2623,12 +2623,23 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, return err; } -static void +static int kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, struct pt_regs *regs, void *data) { struct bpf_kprobe_multi_link *link; + link = container_of(fp, struct bpf_kprobe_multi_link, fp); + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); + return 0; +} + +static void +kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, + struct pt_regs *regs, void *data) +{ + struct bpf_kprobe_multi_link *link; + link = container_of(fp, struct bpf_kprobe_multi_link, fp); kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); } @@ -2754,7 +2765,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr goto error; if (flags & BPF_F_KPROBE_MULTI_RETURN) - link->fp.exit_handler = kprobe_multi_link_handler; + link->fp.exit_handler = kprobe_multi_link_exit_handler; else link->fp.entry_handler = kprobe_multi_link_handler; diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index f222848571f2..9abb3905bc8e 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -27,7 +27,7 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip, struct rethook_node *rh = NULL; struct fprobe *fp; void *entry_data = NULL; - int bit; + int bit, ret; fp = container_of(ops, struct fprobe, ops); if (fprobe_disabled(fp)) @@ -52,11 +52,15 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip, } 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); + ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data); + /* If entry_handler returns !0, nmissed is not counted. */ + if (rh) { + if (ret) + rethook_recycle(rh); + else + rethook_hook(rh, ftrace_get_regs(fregs), true); + } out: ftrace_test_recursion_unlock(bit); } diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c index 976fb3f7cb01..e78176d252ae 100644 --- a/lib/test_fprobe.c +++ b/lib/test_fprobe.c @@ -37,7 +37,7 @@ static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32)) return nest(value + 2); } -static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, +static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs, void *data) { KUNIT_EXPECT_FALSE(current_test, preemptible()); @@ -51,6 +51,8 @@ static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, *(u32 *)data = entry_val; } else KUNIT_EXPECT_NULL(current_test, data); + + return 0; } static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, @@ -74,10 +76,11 @@ static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, KUNIT_EXPECT_NULL(current_test, data); } -static notrace void nest_entry_handler(struct fprobe *fp, unsigned long ip, +static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs, void *data) { KUNIT_EXPECT_FALSE(current_test, preemptible()); + return 0; } static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip, diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c index dd794990ad7e..4efc8feb6277 100644 --- a/samples/fprobe/fprobe_example.c +++ b/samples/fprobe/fprobe_example.c @@ -48,8 +48,8 @@ static void show_backtrace(void) stack_trace_print(stacks, len, 24); } -static void sample_entry_handler(struct fprobe *fp, unsigned long ip, - struct pt_regs *regs, void *data) +static int sample_entry_handler(struct fprobe *fp, unsigned long ip, + struct pt_regs *regs, void *data) { if (use_trace) /* @@ -62,6 +62,7 @@ static void sample_entry_handler(struct fprobe *fp, unsigned long ip, nhit++; if (stackdump) show_backtrace(); + return 0; } static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs,