From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E11F14A12 for ; Sat, 23 Dec 2023 05:22:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="DJPE3TrT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703308947; x=1734844947; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=yzrGfBYG2n+AJNKK6K2eUlm3eQFCK8KMAhWJA5AVc3k=; b=DJPE3TrTPIUmXR3slIpFY89tY/u2929DKOl3BtekEvoYTAGgsYEWgrZC xEArv7fcHri20QJKpihtYSJr1kUK+JWhQIzMydVjh9ZBofcH3yOhAsNzi zuRTO6UsEUsFRLq9UV+jvt7lv/ETlFVN+w94apVMbsCl9FHdcJ+lzVVNo NyKVYLr20hm0JUFbxv7F1SKpZX3eA/9Cdvb5d2g62kcwkvAnNpExAvrVl AUf1e3V9L2g/6eVvRUD5wrxOjJ6//y77bHVMQ/pryXnKJLA8ihSNSGJeA YD2XFceC0FSASSGgJQF7nozvHMIgkPAruOSLsqJzLbtYLXqeCWFV4tjrk A==; X-IronPort-AV: E=McAfee;i="6600,9927,10932"; a="393346322" X-IronPort-AV: E=Sophos;i="6.04,298,1695711600"; d="scan'208";a="393346322" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2023 21:22:27 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10932"; a="1108694264" X-IronPort-AV: E=Sophos;i="6.04,298,1695711600"; d="scan'208";a="1108694264" Received: from rex-z390-aorus-pro.sh.intel.com ([10.239.161.21]) by fmsmga005.fm.intel.com with ESMTP; 22 Dec 2023 21:22:25 -0800 From: Rex Zhang To: lijun.pan@intel.com Cc: dave.jiang@intel.com, dmaengine@vger.kernel.org, fenghua.yu@intel.com, rex.zhang@intel.com, vkoul@kernel.org Subject: Re: [PATCH] dmaengine: idxd: Convert spinlock to mutex to lock evl workqueue Date: Sat, 23 Dec 2023 13:21:51 +0800 Message-Id: <20231223052151.978892-1-rex.zhang@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <511cbc9a-632b-4a7e-a57d-01a21ba904a6@intel.com> References: <511cbc9a-632b-4a7e-a57d-01a21ba904a6@intel.com> Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Lijun, On 2023-12-20 at 19:17:20 -0600, Lijun Pan wrote: > > > On 12/19/2023 9:53 PM, Rex Zhang wrote: > > The drain_workqueue() is not in a locked context. In the multi-task case, > > it's possible to call queue_work() when drain_workqueue() is ongoing, then > > it can cause Call Trace due to pushing a work into a draining workqueue: > > Call Trace: > > > > ? __warn+0x7d/0x140 > > ? __queue_work+0x2b2/0x440 > > ? report_bug+0x1f8/0x200 > > ? handle_bug+0x3c/0x70 > > ? exc_invalid_op+0x18/0x70 > > ? asm_exc_invalid_op+0x1a/0x20 > > ? __queue_work+0x2b2/0x440 > > queue_work_on+0x28/0x30 > > idxd_misc_thread+0x303/0x5a0 [idxd] > > ? __schedule+0x369/0xb40 > > ? __pfx_irq_thread_fn+0x10/0x10 > > ? irq_thread+0xbc/0x1b0 > > irq_thread_fn+0x21/0x70 > > irq_thread+0x102/0x1b0 > > ? preempt_count_add+0x74/0xa0 > > ? __pfx_irq_thread_dtor+0x10/0x10 > > ? __pfx_irq_thread+0x10/0x10 > > kthread+0x103/0x140 > > ? __pfx_kthread+0x10/0x10 > > ret_from_fork+0x31/0x50 > > ? __pfx_kthread+0x10/0x10 > > ret_from_fork_asm+0x1b/0x30 > > > > The original locker for event log was spinlock, drain_workqueue() can't > > s/locker/lock > > Other than that, > > Tested-by: Lijun Pan > Reviewed-by: Lijun Pan Thanks for pointing out. Will update. > > be in a spinlocked context because it may cause task rescheduling. The > > spinlock was called in thread and irq thread context, the current usages > > does not require a spinlock for event log, so it's feasible to convert > > spinlock to mutex. > > For putting drain_workqueue() into a locked context, convert the spinlock > > to mutex, then lock drain_workqueue() by mutex. > > > > Fixes: c40bd7d9737b ("dmaengine: idxd: process user page faults for completion record") > > Signed-off-by: Rex Zhang > > Reviewed-by: Dave Jiang > > Reviewed-by: Fenghua Yu > > --- > > drivers/dma/idxd/cdev.c | 5 ++--- > > drivers/dma/idxd/debugfs.c | 4 ++-- > > drivers/dma/idxd/device.c | 8 ++++---- > > drivers/dma/idxd/idxd.h | 2 +- > > drivers/dma/idxd/init.c | 2 +- > > drivers/dma/idxd/irq.c | 4 ++-- > > 6 files changed, 12 insertions(+), 13 deletions(-) > > > > diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c > > index 0423655f5a88..556cac187612 100644 > > --- a/drivers/dma/idxd/cdev.c > > +++ b/drivers/dma/idxd/cdev.c > > @@ -342,7 +342,7 @@ static void idxd_cdev_evl_drain_pasid(struct idxd_wq *wq, u32 pasid) > > if (!evl) > > return; > > - spin_lock(&evl->lock); > > + mutex_lock(&evl->lock); > > status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET); > > t = status.tail; > > h = evl->head; > > @@ -354,9 +354,8 @@ static void idxd_cdev_evl_drain_pasid(struct idxd_wq *wq, u32 pasid) > > set_bit(h, evl->bmap); > > h = (h + 1) % size; > > } > > - spin_unlock(&evl->lock); > > - > > drain_workqueue(wq->wq); > > + mutex_unlock(&evl->lock); > > } > > static int idxd_cdev_release(struct inode *node, struct file *filep) > > diff --git a/drivers/dma/idxd/debugfs.c b/drivers/dma/idxd/debugfs.c > > index 9cfbd9b14c4c..7f689b3aff65 100644 > > --- a/drivers/dma/idxd/debugfs.c > > +++ b/drivers/dma/idxd/debugfs.c > > @@ -66,7 +66,7 @@ static int debugfs_evl_show(struct seq_file *s, void *d) > > if (!evl || !evl->log) > > return 0; > > - spin_lock(&evl->lock); > > + mutex_lock(&evl->lock); > > h = evl->head; > > evl_status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET); > > @@ -87,7 +87,7 @@ static int debugfs_evl_show(struct seq_file *s, void *d) > > dump_event_entry(idxd, s, i, &count, processed); > > } > > - spin_unlock(&evl->lock); > > + mutex_unlock(&evl->lock); > > return 0; > > } > > diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c > > index 8f754f922217..042e076a6f2a 100644 > > --- a/drivers/dma/idxd/device.c > > +++ b/drivers/dma/idxd/device.c > > @@ -770,7 +770,7 @@ static int idxd_device_evl_setup(struct idxd_device *idxd) > > goto err_alloc; > > } > > - spin_lock(&evl->lock); > > + mutex_lock(&evl->lock); > > evl->log = addr; > > evl->dma = dma_addr; > > evl->log_size = size; > > @@ -791,7 +791,7 @@ static int idxd_device_evl_setup(struct idxd_device *idxd) > > gencfg.evl_en = 1; > > iowrite32(gencfg.bits, idxd->reg_base + IDXD_GENCFG_OFFSET); > > - spin_unlock(&evl->lock); > > + mutex_unlock(&evl->lock); > > return 0; > > err_alloc: > > @@ -811,7 +811,7 @@ static void idxd_device_evl_free(struct idxd_device *idxd) > > if (!gencfg.evl_en) > > return; > > - spin_lock(&evl->lock); > > + mutex_lock(&evl->lock); > > gencfg.evl_en = 0; > > iowrite32(gencfg.bits, idxd->reg_base + IDXD_GENCFG_OFFSET); > > @@ -826,7 +826,7 @@ static void idxd_device_evl_free(struct idxd_device *idxd) > > bitmap_free(evl->bmap); > > evl->log = NULL; > > evl->size = IDXD_EVL_SIZE_MIN; > > - spin_unlock(&evl->lock); > > + mutex_unlock(&evl->lock); > > } > > static void idxd_group_config_write(struct idxd_group *group) > > diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h > > index 1e89c80a07fc..b925c972b99b 100644 > > --- a/drivers/dma/idxd/idxd.h > > +++ b/drivers/dma/idxd/idxd.h > > @@ -283,7 +283,7 @@ struct idxd_driver_data { > > struct idxd_evl { > > /* Lock to protect event log access. */ > > - spinlock_t lock; > > + struct mutex lock; > > void *log; > > dma_addr_t dma; > > /* Total size of event log = number of entries * entry size. */ > > diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c > > index 0eb1c827a215..611101f99405 100644 > > --- a/drivers/dma/idxd/init.c > > +++ b/drivers/dma/idxd/init.c > > @@ -351,7 +351,7 @@ static int idxd_init_evl(struct idxd_device *idxd) > > if (!evl) > > return -ENOMEM; > > - spin_lock_init(&evl->lock); > > + mutex_init(&evl->lock); > > evl->size = IDXD_EVL_SIZE_MIN; > > idxd->evl_cache = kmem_cache_create(dev_name(idxd_confdev(idxd)), > > diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c > > index 2183d7f9cdbd..3037eda986de 100644 > > --- a/drivers/dma/idxd/irq.c > > +++ b/drivers/dma/idxd/irq.c > > @@ -363,7 +363,7 @@ static void process_evl_entries(struct idxd_device *idxd) > > evl_status.bits = 0; > > evl_status.int_pending = 1; > > - spin_lock(&evl->lock); > > + mutex_lock(&evl->lock); > > /* Clear interrupt pending bit */ > > iowrite32(evl_status.bits_upper32, > > idxd->reg_base + IDXD_EVLSTATUS_OFFSET + sizeof(u32)); > > @@ -381,7 +381,7 @@ static void process_evl_entries(struct idxd_device *idxd) > > evl->head = h; > > evl_status.head = h; > > iowrite32(evl_status.bits_lower32, idxd->reg_base + IDXD_EVLSTATUS_OFFSET); > > - spin_unlock(&evl->lock); > > + mutex_unlock(&evl->lock); > > } > > irqreturn_t idxd_misc_thread(int vec, void *data)