From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FD14C433EF for ; Mon, 18 Oct 2021 03:40:12 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3507761250 for ; Mon, 18 Oct 2021 03:40:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3507761250 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:References:To:From:Subject:Reply-To:Cc:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=ogrDsRm1/CJworbwl4uLZ2awrR9G+5JSZ1uziwLhlB0=; b=lIWZEJECX5SPZectXssfyMMZ4A RFUYNRHX6gJC55UNzgMU4J0c13AMfdcWxKBGaXPF2udLsq2SGLI/O/99nPnlZ/VE8Y9njyAuILY63 A69PYG/C7TmR9+QUXeEWM0X3SBzoQrFvW8/jCeIM86ywIaTfTUWRMUVsuCp1x1gtrrGFQS9cvvXJE 05kP720XhLHxYYYN6eYdrd1PZlnNOh9oM+NJVKKvNJeQTE2R8fI/gn1f8rjQGSiKOMWntWFVOfjvF zpfrcyH/WiULthoQI2N7nLOn14PP3wu88L1BaiYUw847TB5FgwSfqztfj9qTyPJJ4DT2F94R8CyV9 DQuPRlzg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mcJVO-00DvF1-E7; Mon, 18 Oct 2021 03:40:06 +0000 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mcJVK-00DvBp-I1 for linux-riscv@lists.infradead.org; Mon, 18 Oct 2021 03:40:04 +0000 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R531e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04426; MF=yun.wang@linux.alibaba.com; NM=1; PH=DS; RN=31; SR=0; TI=SMTPD_---0UsUN0R9_1634528397; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0UsUN0R9_1634528397) by smtp.aliyun-inc.com(127.0.0.1); Mon, 18 Oct 2021 11:39:58 +0800 Subject: [PATCH v4 2/2] ftrace: do CPU checking after preemption disabled From: =?UTF-8?B?546L6LSH?= To: Guo Ren , Steven Rostedt , Ingo Molnar , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Colin Ian King , Masami Hiramatsu , "Peter Zijlstra (Intel)" , Nicholas Piggin , Jisheng Zhang , linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, live-patching@vger.kernel.org References: <32a36348-69ee-6464-390c-3a8d6e9d2b53@linux.alibaba.com> Message-ID: Date: Mon, 18 Oct 2021 11:39:56 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <32a36348-69ee-6464-390c-3a8d6e9d2b53@linux.alibaba.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211017_204002_781523_B0BCA6B9 X-CRM114-Status: GOOD ( 12.71 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org With CONFIG_DEBUG_PREEMPT we observed reports like: BUG: using smp_processor_id() in preemptible caller is perf_ftrace_function_call+0x6f/0x2e0 CPU: 1 PID: 680 Comm: a.out Not tainted Call Trace: dump_stack_lvl+0x8d/0xcf check_preemption_disabled+0x104/0x110 ? optimize_nops.isra.7+0x230/0x230 ? text_poke_bp_batch+0x9f/0x310 perf_ftrace_function_call+0x6f/0x2e0 ... __text_poke+0x5/0x620 text_poke_bp_batch+0x9f/0x310 This telling us the CPU could be changed after task is preempted, and the checking on CPU before preemption will be invalid. Since now ftrace_test_recursion_trylock() will help to disable the preemption, this patch just do the checking after trylock() to address the issue. CC: Steven Rostedt Reported-by: Abaci Signed-off-by: Michael Wang --- kernel/trace/trace_event_perf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 6aed10e..fba8cb7 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -441,13 +441,13 @@ void perf_trace_buf_update(void *record, u16 type) if (!rcu_is_watching()) return; - if ((unsigned long)ops->private != smp_processor_id()) - return; - bit = ftrace_test_recursion_trylock(ip, parent_ip); if (bit < 0) return; + if ((unsigned long)ops->private != smp_processor_id()) + goto out; + event = container_of(ops, struct perf_event, ftrace_ops); /* -- 1.8.3.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv