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 X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 E8CBFC433B4 for ; Sat, 15 May 2021 11:04:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBE47613D4 for ; Sat, 15 May 2021 11:04:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234364AbhEOLF7 (ORCPT ); Sat, 15 May 2021 07:05:59 -0400 Received: from mail.loongson.cn ([114.242.206.163]:48308 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S233077AbhEOLD1 (ORCPT ); Sat, 15 May 2021 07:03:27 -0400 Received: from linux.localdomain (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Axrcgpqp9g598WAA--.13691S4; Sat, 15 May 2021 19:02:08 +0800 (CST) From: Tiezhu Yang To: Thomas Bogendoerfer Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, Xuefeng Li , Steven Rostedt Subject: [PATCH 2/2] MIPS: Fix kernel hang under FUNCTION_GRAPH_TRACER and PREEMPT_TRACER Date: Sat, 15 May 2021 19:02:01 +0800 Message-Id: <1621076521-22412-3-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1621076521-22412-1-git-send-email-yangtiezhu@loongson.cn> References: <1621076521-22412-1-git-send-email-yangtiezhu@loongson.cn> X-CM-TRANSID: AQAAf9Axrcgpqp9g598WAA--.13691S4 X-Coremail-Antispam: 1UD129KBjvJXoWxZFy5CF4kArW3uF4ftry3CFg_yoW5XF1Upr 4Ika4vy3y8XayYg3sFvr18Zr13Xan7t3s2yFyUCayfZws8AF4kXr1xtw18XF1jqr95XayS qas7AF4j9a18Z3JanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBa14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26r1I6r4UM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1l84 ACjcxK6I8E87Iv67AKxVWxJr0_GcWl84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AI xVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20x vE14v26r1j6r18McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xv r2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkIecxEwVAFwVW8KwCF04k20x vY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I 3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIx AIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAI cVCF04k26cxKx2IYs7xG6r1I6r4UMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2js IEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUOXowUUUUU= X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When update the latest mainline kernel with the following three configs, the kernel hangs during startup: (1) CONFIG_FUNCTION_GRAPH_TRACER=y (2) CONFIG_PREEMPT_TRACER=y (3) CONFIG_FTRACE_STARTUP_TEST=y When update the latest mainline kernel with the above two configs (1) and (2), the kernel starts normally, but it still hangs when execute the following command: echo "function_graph" > /sys/kernel/debug/tracing/current_tracer Without CONFIG_PREEMPT_TRACER=y, the above two kinds of kernel hangs disappeared, so it seems that CONFIG_PREEMPT_TRACER has some influences with function_graph tracer at the first glance. I use ejtag to find out the epc address is related with preempt_enable() in the file arch/mips/lib/mips-atomic.c, because function tracing can trace the preempt_{enable,disable} calls that are traced, replace them with preempt_{enable,disable}_notrace to prevent function tracing from going into an infinite loop, and then it can fix the kernel hang issue. By the way, it seems that this commit is a complement and improvement of commit f93a1a00f2bd ("MIPS: Fix crash that occurs when function tracing is enabled"). Signed-off-by: Tiezhu Yang Cc: Steven Rostedt --- arch/mips/lib/mips-atomic.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/mips/lib/mips-atomic.c b/arch/mips/lib/mips-atomic.c index de03838..a9b72ea 100644 --- a/arch/mips/lib/mips-atomic.c +++ b/arch/mips/lib/mips-atomic.c @@ -37,7 +37,7 @@ */ notrace void arch_local_irq_disable(void) { - preempt_disable(); + preempt_disable_notrace(); __asm__ __volatile__( " .set push \n" @@ -53,7 +53,7 @@ notrace void arch_local_irq_disable(void) : /* no inputs */ : "memory"); - preempt_enable(); + preempt_enable_notrace(); } EXPORT_SYMBOL(arch_local_irq_disable); @@ -61,7 +61,7 @@ notrace unsigned long arch_local_irq_save(void) { unsigned long flags; - preempt_disable(); + preempt_disable_notrace(); __asm__ __volatile__( " .set push \n" @@ -78,7 +78,7 @@ notrace unsigned long arch_local_irq_save(void) : /* no inputs */ : "memory"); - preempt_enable(); + preempt_enable_notrace(); return flags; } @@ -88,7 +88,7 @@ notrace void arch_local_irq_restore(unsigned long flags) { unsigned long __tmp1; - preempt_disable(); + preempt_disable_notrace(); __asm__ __volatile__( " .set push \n" @@ -106,7 +106,7 @@ notrace void arch_local_irq_restore(unsigned long flags) : "0" (flags) : "memory"); - preempt_enable(); + preempt_enable_notrace(); } EXPORT_SYMBOL(arch_local_irq_restore); -- 2.1.0