From patchwork Thu Oct 12 09:47:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Junhao He X-Patchwork-Id: 13418728 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 1621ACDB46E for ; Thu, 12 Oct 2023 09:47:18 +0000 (UTC) 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:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=GrhUE8SQNVb30R+1Iaks4ky3l2Txma1X2XVsoYt7rnc=; b=KPLqdn+JDwwctl 5Bw34wDNpwLxdw/RMMymL5gBWwvO1oNIg6o/GCxBUZ9RBLsgPMOJPCf4IdpNTUax9pcuEisSCLRPM c2XY53CIBUm+4Q1ueBv3zlir8dlxy1eEfbZ1INWaO/edAJInYhbk6eiVAgl3SUEv0/p9/ZC+JuA/H XbgTCucs9qkdBsle8OrEOyakt0fotV9K8Lu0jzr8Woy1h4S6ThMMp4lUEMQUeQXonTTy6cXfBe6yV JKzrkLVsHXBRofDor0PwOa2zBWMrHwnC9tfsmaNTjA6tFdMS3LOwJnEsaMPCTJv9sUMbB4z6X9qCr GfPv0EgVUFhM9RN8oKsg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qqsHO-000R99-0k; Thu, 12 Oct 2023 09:46:54 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qqsHE-000R2C-1k for linux-arm-kernel@lists.infradead.org; Thu, 12 Oct 2023 09:46:47 +0000 Received: from dggpeml500002.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4S5l774bjgzVlYB; Thu, 12 Oct 2023 17:42:59 +0800 (CST) Received: from localhost.localdomain (10.69.192.56) by dggpeml500002.china.huawei.com (7.185.36.158) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Thu, 12 Oct 2023 17:46:30 +0800 From: Junhao He To: , CC: , , , , , , , Subject: [PATCH 1/3] coresight: ultrasoc-smb: fix sleep while close preempt in enable_smb Date: Thu, 12 Oct 2023 17:47:04 +0800 Message-ID: <20231012094706.21565-2-hejunhao3@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20231012094706.21565-1-hejunhao3@huawei.com> References: <20231012094706.21565-1-hejunhao3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.56] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500002.china.huawei.com (7.185.36.158) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231012_024645_032426_1F2CC314 X-CRM114-Status: GOOD ( 18.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When we to enable the SMB by perf, the perf sched will call perf_ctx_lock() to close system preempt in event_function_call(). But SMB::enable_smb() use mutex to lock the critical section, which may sleep. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 153023, name: perf 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+0xae8/0x2b48 softirqs last enabled at (0): [] copy_process+0xae8/0x2b48 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 2 PID: 153023 Comm: perf Kdump: loaded Tainted: G W O 6.5.0-rc4+ #1 Call trace: ... __mutex_lock+0xbc/0xa70 mutex_lock_nested+0x34/0x48 smb_update_buffer+0x58/0x360 [ultrasoc_smb] etm_event_stop+0x204/0x2d8 [coresight] etm_event_del+0x1c/0x30 [coresight] event_sched_out+0x17c/0x3b8 group_sched_out.part.0+0x5c/0x208 __perf_event_disable+0x15c/0x210 event_function+0xe0/0x230 remote_function+0xb4/0xe8 generic_exec_single+0x160/0x268 smp_call_function_single+0x20c/0x2a0 event_function_call+0x20c/0x220 _perf_event_disable+0x5c/0x90 perf_event_for_each_child+0x58/0xc0 _perf_ioctl+0x34c/0x1250 perf_ioctl+0x64/0x98 ... Use spinlock replace mutex to control driver data access to one at a time. But the function copy_to_user() may sleep so spinlock do not to lock it. Fixes: 06f5c2926aaa ("drivers/coresight: Add UltraSoc System Memory Buffer driver") Signed-off-by: Junhao He --- drivers/hwtracing/coresight/ultrasoc-smb.c | 36 ++++++++++------------ drivers/hwtracing/coresight/ultrasoc-smb.h | 6 ++-- 2 files changed, 19 insertions(+), 23 deletions(-) diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c b/drivers/hwtracing/coresight/ultrasoc-smb.c index e9a32a97fbee..b08a619d1116 100644 --- a/drivers/hwtracing/coresight/ultrasoc-smb.c +++ b/drivers/hwtracing/coresight/ultrasoc-smb.c @@ -99,7 +99,7 @@ static int smb_open(struct inode *inode, struct file *file) struct smb_drv_data, miscdev); int ret = 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); if (drvdata->reading) { ret = -EBUSY; @@ -115,7 +115,7 @@ static int smb_open(struct inode *inode, struct file *file) drvdata->reading = true; out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return ret; } @@ -132,10 +132,8 @@ static ssize_t smb_read(struct file *file, char __user *data, size_t len, if (!len) return 0; - mutex_lock(&drvdata->mutex); - if (!sdb->data_size) - goto out; + return 0; to_copy = min(sdb->data_size, len); @@ -145,20 +143,18 @@ static ssize_t smb_read(struct file *file, char __user *data, size_t len, if (copy_to_user(data, sdb->buf_base + sdb->buf_rdptr, to_copy)) { dev_dbg(dev, "Failed to copy data to user\n"); - to_copy = -EFAULT; - goto out; + return -EFAULT; } + spin_lock(&drvdata->spinlock); *ppos += to_copy; - smb_update_read_ptr(drvdata, to_copy); - dev_dbg(dev, "%zu bytes copied\n", to_copy); -out: if (!sdb->data_size) smb_reset_buffer(drvdata); - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); + dev_dbg(dev, "%zu bytes copied\n", to_copy); return to_copy; } @@ -167,9 +163,9 @@ static int smb_release(struct inode *inode, struct file *file) struct smb_drv_data *drvdata = container_of(file->private_data, struct smb_drv_data, miscdev); - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); drvdata->reading = false; - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return 0; } @@ -262,7 +258,7 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode, struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent); int ret = 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); /* Do nothing, the trace data is reading by other interface now */ if (drvdata->reading) { @@ -294,7 +290,7 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode, dev_dbg(&csdev->dev, "Ultrasoc SMB enabled\n"); out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return ret; } @@ -304,7 +300,7 @@ static int smb_disable(struct coresight_device *csdev) struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent); int ret = 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); if (drvdata->reading) { ret = -EBUSY; @@ -327,7 +323,7 @@ static int smb_disable(struct coresight_device *csdev) dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n"); out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return ret; } @@ -408,7 +404,7 @@ static unsigned long smb_update_buffer(struct coresight_device *csdev, if (!buf) return 0; - mutex_lock(&drvdata->mutex); + spin_lock(&drvdata->spinlock); /* Don't do anything if another tracer is using this sink. */ if (atomic_read(&csdev->refcnt) != 1) @@ -432,7 +428,7 @@ static unsigned long smb_update_buffer(struct coresight_device *csdev, if (!buf->snapshot && lost) perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); out: - mutex_unlock(&drvdata->mutex); + spin_unlock(&drvdata->spinlock); return data_size; } @@ -590,7 +586,7 @@ static int smb_probe(struct platform_device *pdev) return ret; } - mutex_init(&drvdata->mutex); + spin_lock_init(&drvdata->spinlock); drvdata->pid = -1; ret = smb_register_sink(pdev, drvdata); diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.h b/drivers/hwtracing/coresight/ultrasoc-smb.h index d2e14e8d2c8a..82a44c14a882 100644 --- a/drivers/hwtracing/coresight/ultrasoc-smb.h +++ b/drivers/hwtracing/coresight/ultrasoc-smb.h @@ -8,7 +8,7 @@ #define _ULTRASOC_SMB_H #include -#include +#include /* Offset of SMB global registers */ #define SMB_GLB_CFG_REG 0x00 @@ -105,7 +105,7 @@ struct smb_data_buffer { * @csdev: Component vitals needed by the framework. * @sdb: Data buffer for SMB. * @miscdev: Specifics to handle "/dev/xyz.smb" entry. - * @mutex: Control data access to one at a time. + * @spinlock: Control data access to one at a time. * @reading: Synchronise user space access to SMB buffer. * @pid: Process ID of the process being monitored by the * session that is using this component. @@ -116,7 +116,7 @@ struct smb_drv_data { struct coresight_device *csdev; struct smb_data_buffer sdb; struct miscdevice miscdev; - struct mutex mutex; + spinlock_t spinlock; bool reading; pid_t pid; enum cs_mode mode;