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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F3ECC433F5 for ; Mon, 28 Feb 2022 18:13:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234370AbiB1SNy (ORCPT ); Mon, 28 Feb 2022 13:13:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241549AbiB1SKD (ORCPT ); Mon, 28 Feb 2022 13:10:03 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C4B1B8213; Mon, 28 Feb 2022 09:50:13 -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 A79BEB815C3; Mon, 28 Feb 2022 17:50:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1BBCC340E7; Mon, 28 Feb 2022 17:50:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646070609; bh=6UwCDOJqRhPGFGmGm2PxiDMylLrzjuY/whP3p9ohKBk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qaBCk5zrYB9zLrP+04pcdUKFg1E9xLrrW4EzoPscoGsFGiw3egCzVn/qejkDO6gYz VENaCBty3YVQN6KRJP30ScJPM1XczIP1X7oTFaisI9CcLhF6bX2/htofLEyRK5zoO5 u+oWFJHILyBnJNaL/M/X1fL/qzavF4ZkeH0MDIcU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Changbin Du , Palmer Dabbelt Subject: [PATCH 5.16 151/164] riscv: fix oops caused by irqsoff latency tracer Date: Mon, 28 Feb 2022 18:25:13 +0100 Message-Id: <20220228172413.489437652@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220228172359.567256961@linuxfoundation.org> References: <20220228172359.567256961@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Changbin Du commit 22e2100b1b07d6f5acc71cc1acb53f680c677d77 upstream. The trace_hardirqs_{on,off}() require the caller to setup frame pointer properly. This because these two functions use macro 'CALLER_ADDR1' (aka. __builtin_return_address(1)) to acquire caller info. If the $fp is used for other purpose, the code generated this macro (as below) could trigger memory access fault. 0xffffffff8011510e <+80>: ld a1,-16(s0) 0xffffffff80115112 <+84>: ld s2,-8(a1) # <-- paging fault here The oops message during booting if compiled with 'irqoff' tracer enabled: [ 0.039615][ T0] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000f8 [ 0.041925][ T0] Oops [#1] [ 0.042063][ T0] Modules linked in: [ 0.042864][ T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.17.0-rc1-00233-g9a20c48d1ed2 #29 [ 0.043568][ T0] Hardware name: riscv-virtio,qemu (DT) [ 0.044343][ T0] epc : trace_hardirqs_on+0x56/0xe2 [ 0.044601][ T0] ra : restore_all+0x12/0x6e [ 0.044721][ T0] epc : ffffffff80126a5c ra : ffffffff80003b94 sp : ffffffff81403db0 [ 0.044801][ T0] gp : ffffffff8163acd8 tp : ffffffff81414880 t0 : 0000000000000020 [ 0.044882][ T0] t1 : 0098968000000000 t2 : 0000000000000000 s0 : ffffffff81403de0 [ 0.044967][ T0] s1 : 0000000000000000 a0 : 0000000000000001 a1 : 0000000000000100 [ 0.045046][ T0] a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 [ 0.045124][ T0] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000054494d45 [ 0.045210][ T0] s2 : ffffffff80003b94 s3 : ffffffff81a8f1b0 s4 : ffffffff80e27b50 [ 0.045289][ T0] s5 : ffffffff81414880 s6 : ffffffff8160fa00 s7 : 00000000800120e8 [ 0.045389][ T0] s8 : 0000000080013100 s9 : 000000000000007f s10: 0000000000000000 [ 0.045474][ T0] s11: 0000000000000000 t3 : 7fffffffffffffff t4 : 0000000000000000 [ 0.045548][ T0] t5 : 0000000000000000 t6 : ffffffff814aa368 [ 0.045620][ T0] status: 0000000200000100 badaddr: 00000000000000f8 cause: 000000000000000d [ 0.046402][ T0] [] restore_all+0x12/0x6e This because the $fp(aka. $s0) register is not used as frame pointer in the assembly entry code. resume_kernel: REG_L s0, TASK_TI_PREEMPT_COUNT(tp) bnez s0, restore_all REG_L s0, TASK_TI_FLAGS(tp) andi s0, s0, _TIF_NEED_RESCHED beqz s0, restore_all call preempt_schedule_irq j restore_all To fix above issue, here we add one extra level wrapper for function trace_hardirqs_{on,off}() so they can be safely called by low level entry code. Signed-off-by: Changbin Du Fixes: 3c4697982982 ("riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt Signed-off-by: Greg Kroah-Hartman --- arch/riscv/kernel/Makefile | 2 ++ arch/riscv/kernel/entry.S | 10 +++++----- arch/riscv/kernel/trace_irq.c | 27 +++++++++++++++++++++++++++ arch/riscv/kernel/trace_irq.h | 11 +++++++++++ 4 files changed, 45 insertions(+), 5 deletions(-) create mode 100644 arch/riscv/kernel/trace_irq.c create mode 100644 arch/riscv/kernel/trace_irq.h --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -50,6 +50,8 @@ obj-$(CONFIG_MODULE_SECTIONS) += module- obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o obj-$(CONFIG_DYNAMIC_FTRACE) += mcount-dyn.o +obj-$(CONFIG_TRACE_IRQFLAGS) += trace_irq.o + obj-$(CONFIG_RISCV_BASE_PMU) += perf_event.o obj-$(CONFIG_PERF_EVENTS) += perf_callchain.o obj-$(CONFIG_HAVE_PERF_REGS) += perf_regs.o --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -108,7 +108,7 @@ _save_context: .option pop #ifdef CONFIG_TRACE_IRQFLAGS - call trace_hardirqs_off + call __trace_hardirqs_off #endif #ifdef CONFIG_CONTEXT_TRACKING @@ -143,7 +143,7 @@ skip_context_tracking: li t0, EXC_BREAKPOINT beq s4, t0, 1f #ifdef CONFIG_TRACE_IRQFLAGS - call trace_hardirqs_on + call __trace_hardirqs_on #endif csrs CSR_STATUS, SR_IE @@ -234,7 +234,7 @@ ret_from_exception: REG_L s0, PT_STATUS(sp) csrc CSR_STATUS, SR_IE #ifdef CONFIG_TRACE_IRQFLAGS - call trace_hardirqs_off + call __trace_hardirqs_off #endif #ifdef CONFIG_RISCV_M_MODE /* the MPP value is too large to be used as an immediate arg for addi */ @@ -270,10 +270,10 @@ restore_all: REG_L s1, PT_STATUS(sp) andi t0, s1, SR_PIE beqz t0, 1f - call trace_hardirqs_on + call __trace_hardirqs_on j 2f 1: - call trace_hardirqs_off + call __trace_hardirqs_off 2: #endif REG_L a0, PT_STATUS(sp) --- /dev/null +++ b/arch/riscv/kernel/trace_irq.c @@ -0,0 +1,27 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022 Changbin Du + */ + +#include +#include +#include "trace_irq.h" + +/* + * trace_hardirqs_on/off require the caller to setup frame pointer properly. + * Otherwise, CALLER_ADDR1 might trigger an pagging exception in kernel. + * Here we add one extra level so they can be safely called by low + * level entry code which $fp is used for other purpose. + */ + +void __trace_hardirqs_on(void) +{ + trace_hardirqs_on(); +} +NOKPROBE_SYMBOL(__trace_hardirqs_on); + +void __trace_hardirqs_off(void) +{ + trace_hardirqs_off(); +} +NOKPROBE_SYMBOL(__trace_hardirqs_off); --- /dev/null +++ b/arch/riscv/kernel/trace_irq.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2022 Changbin Du + */ +#ifndef __TRACE_IRQ_H +#define __TRACE_IRQ_H + +void __trace_hardirqs_on(void); +void __trace_hardirqs_off(void); + +#endif /* __TRACE_IRQ_H */