From nobody Thu Apr 9 04:42:12 2026 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 C7C10C4332F for ; Wed, 2 Nov 2022 11:20:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230461AbiKBLUW (ORCPT ); Wed, 2 Nov 2022 07:20:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229590AbiKBLUU (ORCPT ); Wed, 2 Nov 2022 07:20:20 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id BCB5B23EB1 for ; Wed, 2 Nov 2022 04:20:18 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C994C1FB; Wed, 2 Nov 2022 04:20:24 -0700 (PDT) Received: from e126815.warwick.arm.com (e126815.arm.com [10.32.32.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 8D75F3F5A1; Wed, 2 Nov 2022 04:20:16 -0700 (PDT) From: James Clark To: stable@kernel.org Cc: Suzuki.Poulose@arm.com, James Clark , Aishwarya TCV , Cristian Marussi , Suzuki K Poulose , Mike Leach , Mathieu Poirier , Leo Yan , Alexander Shishkin , Greg Kroah-Hartman , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 5.10] coresight: cti: Fix hang in cti_disable_hw() Date: Wed, 2 Nov 2022 11:20:03 +0000 Message-Id: <20221102112003.2318583-1-james.clark@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" commit 6746eae4bbaddcc16b40efb33dab79210828b3ce upstream. cti_enable_hw() and cti_disable_hw() are called from an atomic context so shouldn't use runtime PM because it can result in a sleep when communicating with firmware. This can cause a hang when running the Perf Coresight tests or running this command: perf record -e cs_etm//u -- ls With lock and scheduler debugging enabled the following is output: coresight cti_sys0: cti_enable_hw -- dev:cti_sys0 parent: 20020000.cti BUG: sleeping function called from invalid context at drivers/base/power= /runtime.c:1151 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 330, name: perf= -exec preempt_count: 2, expected: 0 RCU nest depth: 0, expected: 0 INFO: lockdep is turned off. irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [] copy_process+0xa0c/0= x1948 softirqs last enabled at (0): [] copy_process+0xa0c/0= x1948 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 3 PID: 330 Comm: perf-exec Not tainted 6.0.0-00053-g042116d99298 #7 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Developmen= t Platform, BIOS EDK II Sep 13 2022 Call trace: dump_backtrace+0x134/0x140 show_stack+0x20/0x58 dump_stack_lvl+0x8c/0xb8 dump_stack+0x18/0x34 __might_resched+0x180/0x228 __might_sleep+0x50/0x88 __pm_runtime_resume+0xac/0xb0 cti_enable+0x44/0x120 coresight_control_assoc_ectdev+0xc0/0x150 coresight_enable_path+0xb4/0x288 etm_event_start+0x138/0x170 etm_event_add+0x48/0x70 event_sched_in.isra.122+0xb4/0x280 merge_sched_in+0x1fc/0x3d0 visit_groups_merge.constprop.137+0x16c/0x4b0 ctx_sched_in+0x114/0x1f0 perf_event_sched_in+0x60/0x90 ctx_resched+0x68/0xb0 perf_event_exec+0x138/0x508 begin_new_exec+0x52c/0xd40 load_elf_binary+0x6b8/0x17d0 bprm_execve+0x360/0x7f8 do_execveat_common.isra.47+0x218/0x238 __arm64_sys_execve+0x48/0x60 invoke_syscall+0x4c/0x110 el0_svc_common.constprop.4+0xfc/0x120 do_el0_svc+0x34/0xc0 el0_svc+0x40/0x98 el0t_64_sync_handler+0x98/0xc0 el0t_64_sync+0x170/0x174 Fix the issue by removing the runtime PM calls completely. They are not needed here because it must have already been done when building the path for a trace. Fixes: 835d722ba10a ("coresight: cti: Initial CoreSight CTI Driver") Cc: stable # 5.10.x Reported-by: Aishwarya TCV Reported-by: Cristian Marussi Suggested-by: Suzuki K Poulose Reviewed-by: Mike Leach Tested-by: Mike Leach [ Fix build warnings ] Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20221025131032.1149459-1-suzuki.poulose@arm= .com Signed-off-by: James Clark --- drivers/hwtracing/coresight/coresight-cti-core.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwt= racing/coresight/coresight-cti-core.c index 0276700c246d..90270696206c 100644 --- a/drivers/hwtracing/coresight/coresight-cti-core.c +++ b/drivers/hwtracing/coresight/coresight-cti-core.c @@ -90,11 +90,9 @@ void cti_write_all_hw_regs(struct cti_drvdata *drvdata) static int cti_enable_hw(struct cti_drvdata *drvdata) { struct cti_config *config =3D &drvdata->config; - struct device *dev =3D &drvdata->csdev->dev; unsigned long flags; int rc =3D 0; =20 - pm_runtime_get_sync(dev->parent); spin_lock_irqsave(&drvdata->spinlock, flags); =20 /* no need to do anything if enabled or unpowered*/ @@ -119,7 +117,6 @@ static int cti_enable_hw(struct cti_drvdata *drvdata) /* cannot enable due to error */ cti_err_not_enabled: spin_unlock_irqrestore(&drvdata->spinlock, flags); - pm_runtime_put(dev->parent); return rc; } =20 @@ -153,7 +150,6 @@ static void cti_cpuhp_enable_hw(struct cti_drvdata *drv= data) static int cti_disable_hw(struct cti_drvdata *drvdata) { struct cti_config *config =3D &drvdata->config; - struct device *dev =3D &drvdata->csdev->dev; =20 spin_lock(&drvdata->spinlock); =20 @@ -174,7 +170,6 @@ static int cti_disable_hw(struct cti_drvdata *drvdata) coresight_disclaim_device_unlocked(drvdata->base); CS_LOCK(drvdata->base); spin_unlock(&drvdata->spinlock); - pm_runtime_put(dev->parent); return 0; =20 /* not disabled this call */ --=20 2.25.1