From patchwork Mon Dec 28 12:51:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 353552 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A603C433DB for ; Mon, 28 Dec 2020 14:37:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2EBBE2063A for ; Mon, 28 Dec 2020 14:37:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2505615AbgL1Og7 (ORCPT ); Mon, 28 Dec 2020 09:36:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:40976 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2504852AbgL1OdA (ORCPT ); Mon, 28 Dec 2020 09:33:00 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 729C020731; Mon, 28 Dec 2020 14:32:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165939; bh=QPsKZHQza4henJNpGHixnqaxrxt6Z2FKmPHmCG5Y2+o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hu43qM1RVRmBllGn3NqQlRkJy1UqJFTtcpMPFLg+zr/eCvBKzuyT4mxRNF1dSM+lO Swwp/FPhqR/fd/9WiPYmXXgtlSQjVwaoY8DeaVSEXR/OR1mtPo0p6T/Tyovp0Ne0sW iOzFNrGMxNPamYbhELhKaAj6U7CzeofKGlgWGg5Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ingo Molnar , Masami Hiramatsu , "Steven Rostedt (VMware)" Subject: [PATCH 5.10 707/717] tracing: Disable ftrace selftests when any tracer is running Date: Mon, 28 Dec 2020 13:51:45 +0100 Message-Id: <20201228125054.861218470@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Masami Hiramatsu commit 60efe21e5976d3d4170a8190ca76a271d6419754 upstream. Disable ftrace selftests when any tracer (kernel command line options like ftrace=, trace_events=, kprobe_events=, and boot-time tracing) starts running because selftest can disturb it. Currently ftrace= and trace_events= are checked, but kprobe_events has a different flag, and boot-time tracing didn't checked. This unifies the disabled flag and all of those boot-time tracing features sets the flag. This also fixes warnings on kprobe-event selftest (CONFIG_FTRACE_STARTUP_TEST=y and CONFIG_KPROBE_EVENTS=y) with boot-time tracing (ftrace.event.kprobes.EVENT.probes) like below; [ 59.803496] trace_kprobe: Testing kprobe tracing: [ 59.804258] ------------[ cut here ]------------ [ 59.805682] WARNING: CPU: 3 PID: 1 at kernel/trace/trace_kprobe.c:1987 kprobe_trace_self_tests_ib [ 59.806944] Modules linked in: [ 59.807335] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc7+ #172 [ 59.808029] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/204 [ 59.808999] RIP: 0010:kprobe_trace_self_tests_init+0x5f/0x42b [ 59.809696] Code: e8 03 00 00 48 c7 c7 30 8e 07 82 e8 6d 3c 46 ff 48 c7 c6 00 b2 1a 81 48 c7 c7 7 [ 59.812439] RSP: 0018:ffffc90000013e78 EFLAGS: 00010282 [ 59.813038] RAX: 00000000ffffffef RBX: 0000000000000000 RCX: 0000000000049443 [ 59.813780] RDX: 0000000000049403 RSI: 0000000000049403 RDI: 000000000002deb0 [ 59.814589] RBP: ffffc90000013e90 R08: 0000000000000001 R09: 0000000000000001 [ 59.815349] R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffef [ 59.816138] R13: ffff888004613d80 R14: ffffffff82696940 R15: ffff888004429138 [ 59.816877] FS: 0000000000000000(0000) GS:ffff88807dcc0000(0000) knlGS:0000000000000000 [ 59.817772] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 59.818395] CR2: 0000000001a8dd38 CR3: 0000000002222000 CR4: 00000000000006a0 [ 59.819144] Call Trace: [ 59.819469] ? init_kprobe_trace+0x6b/0x6b [ 59.819948] do_one_initcall+0x5f/0x300 [ 59.820392] ? rcu_read_lock_sched_held+0x4f/0x80 [ 59.820916] kernel_init_freeable+0x22a/0x271 [ 59.821416] ? rest_init+0x241/0x241 [ 59.821841] kernel_init+0xe/0x10f [ 59.822251] ret_from_fork+0x22/0x30 [ 59.822683] irq event stamp: 16403349 [ 59.823121] hardirqs last enabled at (16403359): [] console_unlock+0x48e/0x580 [ 59.824074] hardirqs last disabled at (16403368): [] console_unlock+0x3f6/0x580 [ 59.825036] softirqs last enabled at (16403200): [] __do_softirq+0x33a/0x484 [ 59.825982] softirqs last disabled at (16403087): [] asm_call_irq_on_stack+0x10 [ 59.827034] ---[ end trace 200c544775cdfeb3 ]--- [ 59.827635] trace_kprobe: error on probing function entry. Link: https://lkml.kernel.org/r/160741764955.3448999.3347769358299456915.stgit@devnote2 Fixes: 4d655281eb1b ("tracing/boot Add kprobe event support") Cc: Ingo Molnar Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 19 +++++++++++++------ kernel/trace/trace.h | 5 +++++ kernel/trace/trace_boot.c | 2 ++ kernel/trace/trace_events.c | 2 +- kernel/trace/trace_kprobe.c | 9 +++------ kernel/trace/trace_selftest.c | 2 +- 6 files changed, 25 insertions(+), 14 deletions(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -68,10 +68,21 @@ bool ring_buffer_expanded; static bool __read_mostly tracing_selftest_running; /* - * If a tracer is running, we do not want to run SELFTEST. + * If boot-time tracing including tracers/events via kernel cmdline + * is running, we do not want to run SELFTEST. */ bool __read_mostly tracing_selftest_disabled; +#ifdef CONFIG_FTRACE_STARTUP_TEST +void __init disable_tracing_selftest(const char *reason) +{ + if (!tracing_selftest_disabled) { + tracing_selftest_disabled = true; + pr_info("Ftrace startup test is disabled due to %s\n", reason); + } +} +#endif + /* Pipe tracepoints to printk */ struct trace_iterator *tracepoint_print_iter; int tracepoint_printk; @@ -2113,11 +2124,7 @@ int __init register_tracer(struct tracer apply_trace_boot_options(); /* disable other selftests, since this will break it. */ - tracing_selftest_disabled = true; -#ifdef CONFIG_FTRACE_STARTUP_TEST - printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n", - type->name); -#endif + disable_tracing_selftest("running a tracer"); out_unlock: return ret; --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -896,6 +896,8 @@ extern bool ring_buffer_expanded; extern bool tracing_selftest_disabled; #ifdef CONFIG_FTRACE_STARTUP_TEST +extern void __init disable_tracing_selftest(const char *reason); + extern int trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr); extern int trace_selftest_startup_function_graph(struct tracer *trace, @@ -919,6 +921,9 @@ extern int trace_selftest_startup_branch */ #define __tracer_data __refdata #else +static inline void __init disable_tracing_selftest(const char *reason) +{ +} /* Tracers are seldom changed. Optimize when selftests are disabled. */ #define __tracer_data __read_mostly #endif /* CONFIG_FTRACE_STARTUP_TEST */ --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -344,6 +344,8 @@ static int __init trace_boot_init(void) trace_boot_init_one_instance(tr, trace_node); trace_boot_init_instances(trace_node); + disable_tracing_selftest("running boot-time tracing"); + return 0; } /* --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3201,7 +3201,7 @@ static __init int setup_trace_event(char { strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE); ring_buffer_expanded = true; - tracing_selftest_disabled = true; + disable_tracing_selftest("running event tracing"); return 1; } --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -25,11 +25,12 @@ /* Kprobe early definition from command line */ static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; -static bool kprobe_boot_events_enabled __initdata; static int __init set_kprobe_boot_events(char *str) { strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); + disable_tracing_selftest("running kprobe events"); + return 0; } __setup("kprobe_event=", set_kprobe_boot_events); @@ -1887,8 +1888,6 @@ static __init void setup_boot_kprobe_eve ret = trace_run_command(cmd, create_or_delete_trace_kprobe); if (ret) pr_warn("Failed to add event(%d): %s\n", ret, cmd); - else - kprobe_boot_events_enabled = true; cmd = p; } @@ -1973,10 +1972,8 @@ static __init int kprobe_trace_self_test if (tracing_is_disabled()) return -ENODEV; - if (kprobe_boot_events_enabled) { - pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n"); + if (tracing_selftest_disabled) return 0; - } target = kprobe_trace_selftest_target; --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -787,7 +787,7 @@ trace_selftest_startup_function_graph(st /* Have we just recovered from a hang? */ if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) { - tracing_selftest_disabled = true; + disable_tracing_selftest("recovering from a hang"); ret = -1; goto out; }